Considerations for SQL Server on Linux

Introduction and Background

SQL Server has been released for Linux environments too, and after ASP.NET we can now use SQL Server to actually workout our servers on Linux using Microsoft technologies without having to purchase the licenses and pay a fortune. But that is not the case, at least for a while… Why? I will walk you through these critical aspects of the SQL Server and Linux continuum in this post, I am really looking forward to exploring a lot of things right here with you, by reading this post, you will be able to go through many areas of SQL Server on Linux and see if you really need to try it out at the moment or if you need to wait a while before diving any deeper in the platform.

I personally enjoy trying new things out… There are many out there who just try things out, I F… no, no, I dissect things up to share the in-depths of what everything has, what everything says and really is and finally, should you consider it or not. That is the most important part. After all, it is you, who is the main focus of my attention I want to tell you, share with you, what I find. Thus, by reading my post, you will get idea about many things — SQL Server is in its initial versions on Linux so, this post is primarily a feedback, overview of SQL Server and not a rant on the product in anyway.

SQL Server 2016 available on Linux

Now starts the fun part, I believe almost all of you are aware of the fact that SQL Server 2016 is available on Linux after serving Windows only since a great time, plus .NET Core is available on Linux too, and if you have been reading my past articles and blogs you are aware of fact that I am a huge fan of .NET Core framework and how it helps Microsoft to ship their products to other platforms too.

Microsoft announced SQL Server availability on Linux quite a while ago, and many have started downloading and using the product.

Figure 1: SQL Server “heart” Linux. No pun intended. 

Of course the benefit is for Linux users and developers because they now have more options, whether they like SQL Server or not is a different thing in itself. I personally enjoy the tools, such as SQL Server Management Studio, which is a free software to manage databases using SQL Server. The tool can be used for most of the database engines, however Microsoft only engines.

There are many posts that give a good overview and introduction to SQL Server on Linux, and I am not going to dive deeper into them… As I have an exam of Database Systems tomorrow. So, help yourself with a few of,

1. https://www.microsoft.com/en-us/sql-server/sql-server-vnext-including-Linux
2. https://docs.microsoft.com/en-us/sql/linux/sql-server-linux-get-started-tutorial
3. https://blogs.technet.microsoft.com/dataplatforminsider/2016/11/16/announcing-sql-server-on-linux-public-preview-first-preview-of-next-release-of-sql-server/ (This is a must read!)

Without further delay, let us go on to the installation of SQL Server on Linux section, and see how we can get our hands on those binaries.

Installation of SQL Server engine

SQL Server, like on Windows, comes separately from tools. You have to install SQL Server and then you later install the tools required to connect to the engine itself — Note: If you can use .NET Core application, then chances are that you do not even need the SQL Server Tools for Linux at the moment. You can just straight away execute the commands in the terminal, I will show you how… And in my experience I found this method really agile and as per demand.

So, fire up your machines and add the keys for packages that you are going to access, download and install.

$ curl https://packages.microsoft.com/keys/microsoft.asc | sudo apt-key add -
$ curl https://packages.microsoft.com/config/ubuntu/16.04/mssql-server.list | sudo tee /etc/apt/sources.list.d/mssql-server.list

These will set up the repositories to your machine that you can then use to start downloading the packages.

Figure 2: curl executing.

Finally, refresh the sources and start the installation,

$ sudo apt-get update
$ sudo apt-get install mssql-server

You will be prompted to enter “y” and press “Enter” key to continue the installation. This process will download and install the binaries in your system. It downloads the files and scripts that will later on set up the system for your instance, Once the setup finishes, you may execute the following script to start “installation” of SQL Server 2016 on your machine.

Figure 3: SQL Server installed on Ubuntu. 

$ sudo /opt/mssql/bin/sqlservr-setup

Authenticate this script, as it requires a lot of permissions in order to generate the server’s engine on your machine. The default hierarchy is like this,

Figure 4: Files in the installation directory, ready to install engine. 

You can see the setup script in the list, execute it in the terminal and it will guide you through setup.

Figure 5: SQL Server installer requesting user password during installation. 

You will accept the terms, enter password etc. and server will be installed. Simple as that. But yeah, do remember the password you need it later to connect — there is no Trusted_Connection property available in this one.

You can also test the service to see if that is running properly, or running at all by going down to your task manager and looking for the running services. First of all, you can execute the following command to see if the server is running,

$ systemctl status mssql-server

Figure 6: The screenshot shows that the response has everything required to see whether service is running or not.

In most operating systems you can find the same under processes too,

Figure 7: SQL Server collects telemetry information; the last process tells this. 

Once everything is working we can move onwards to download and install tools.

Installing SQL Server 2016 Tools

On Linux, the choice you have is very small and selected. You may download and install a few helpers and tools if you would like, such as “sqlcmd” program. Just giving a short overview of the steps required to install this package and to use it for some tinkering.

The procedure is similar to what we had, add keys, install the server,

$ curl https://packages.microsoft.com/keys/microsoft.asc | sudo apt-key add -
$ curl https://packages.microsoft.com/config/ubuntu/16.04/prod.list | sudo tee /etc/apt/sources.list.d/msprod.list

Then finally use the following command,

$ sudo apt-get update 
$ sudo apt-get install mssql-tools

The installation won’t take longer and you will be able to get the packages that you can later use, I won’t be showing these off a lot.

$ sqlcmd -S localhost -U sa

Do not enter password in the terminal at all, let the program itself ask for the password and user will enter it later, secondly user input will not be shown on the screen.

Figure 8: Result of SQL query in sqlcmd program.

This is enough and I don’t want to talk any more about this tool, plus I do not recommend this at all, why? See the result of SQL query below,

> SELECT serverproperty('edition')
> GO

Figure 9: Result of an SQL query, totally unstructured. 

The results are not properly structured so they are confusing, plus you have to scroll up and down a bit to see them properly. So, what to do then? Instead of using this I am going to teach you how to write your own programs… I already did so, and I thought I should again for .NET Core.

Writing SQL Server connector app in .NET Core

I am going to use .NET Core for this application development part, it is indeed my favorite platform there is. On the .NET world, I wrote the same article using .NET framework, you can read that article here, How to connect SQL Database to your C# program, beginner’s tutorial. That tutorial is a complete guide to SQL Server, targeted at any beginner in the platform field. However in this, I am not going to explain the basics but I am just going to show you how to write the application and how to get the output.

Note: You should read that article for more explanations, I am not going to explain this in depth. I will not be explaining System.Data.SqlClient either, it is available in that post I referred to.

You will start off by creating a new project, restoring it, and finally open it up in Visual Studio Code.

$ dotnet new
$ dotnet restore
$ code .

I ignored the new directory creation process, thinking you guys know it yourself. If you have no idea, consider reading a few of my previous posts for more on this topic, such as, A quick startup using .NET Core on Linux.

After that, add a new file to your project, name it SqlHelper, add a class with same name in it,

using System;
using System.Data.SqlClient;

namespace ConsoleApplication
{
    class SqlHelper 
    {
        private SqlConnection _conn = null;

        public SqlHelper() 
        {
            _conn = new SqlConnection("server=localhost;user id=sa;password=<password>");
            _conn.Open();
            Console.WriteLine("Connected to server.");
        }
    }
}

You still require a simple SQL connection string for your database engine, there is a website that you can use to get your connection strings. I initially told you there is no version of using trusted_connection here because there are no Windows accounts here that we can utilize. Now, call this object from your main class and you will see the result.

using System;

namespace ConsoleApplication
{
    public class Program
    {
        public static void Main(string[] args)
        {
            new SqlHelper();
        }
    }
}

Figure 10: Connected to the server.

The results are promising as they show we can connect to the server here. Now we can move onwards to actually create something useful. Let us just try to execute the commands (that we executed above) in our newly developed system, update the code to start accepting requests of SQL commands.

using System;
using System.Data.SqlClient;

namespace ConsoleApplication
{
    class SqlHelper 
    {
        private SqlConnection _conn = null;

        public SqlHelper() 
        {
            _conn = new SqlConnection("server = localhost; user id = sa; password = <password>");
            _conn.Open();
            Console.WriteLine("Connected to server.");
            _execute();
        }

        private void _execute() 
        {
            if (_conn != null ) 
            {
                Console.BackgroundColor = ConsoleColor.Red;
                Console.ForegroundColor = ConsoleColor.White;
                Console.Write("Note:");
                Console.BackgroundColor = ConsoleColor.Black;
                Console.ForegroundColor = ConsoleColor.Gray;
                Console.WriteLine(" You may enter single line queries only.");

                while(true)
                {
                    Console.Write("SQL> ");
                    string query = Console.ReadLine();
                    using (var command = new SqlCommand(query, _conn)) 
                    {
                        try {
                            using (var reader = command.ExecuteReader()) 
                            {
                                while (reader.Read()) 
                                {
                                    Console.WriteLine(reader.GetString(0));
                                }
                            }
                        } catch (Exception error) {
                            Console.WriteLine(error.Message);
                        }
                    }
                }
            }
        }
    }
}

This will start executing and will request the user to enter SQL commands, you can see how this works below,

Figure 11: Connecting and executing SQL queries on SQL Server. 

So, you have seen that even a simple .NET Core program to write and manage the queries is way better are structuring the sqlcmd program on Linux. You can update this as per needed.

Tips, tricks and considerations…

In this section I will talk about a few of the major concepts that you must know and understand before diving any deeper in SQL Server on Linux at all, if you don’t know these, then chances are you don’t know SQL Server too. So, pay attention.

1. Default Directory?

There are so many articles out there already, yet no one seems to be interested in telling the world where the server gets installed. Where to find the files? How to locate database logs etc?

In Linux, the default directory is, “/var/opt/mssql/<locked out>“. You need to have admin privileges to access and read the content of this directory. So, I got them and entered the directory.

$ sudo dolphin /var/opt/mssql/

“dolphin” is the file manager program in KDE, sorry the display was not so much clear so I selected everything for you too what is inside.

Figure 12: Data in the “data” directory under “mssql” directory.

You can surf the rest of the directory on your own, I thought I should let you know where things actually reside. On your system, in future, it might change. But, until then, enjoy. 😉

2. Edition Installed

On Windows, you are typically asked for edition that you need to install on your machine. On Linux that was not the case and it installed one for us. The default one (and at the moment, only possible one) is SQL Server Developer edition. This edition is free of cost, and it has everything that Enterprise edition has.

To confirm, just execute,

SELECT serverproperty('edition')

Or, have a look above in figure 9 or 11, you can see the edition shown. All of recent products of Microsoft based on .NET Core are x64 only. ARM and x86 are left for future, for now.

3. Usage Permissions

Yes, you can feel free to download, use and try this product out, but remember you cannot use it in production or with production data. This is the only difference in Enterprise and Developer edition of SQL Server 2016.

If you head over to SQL Server 2016 editions, you can see the chart clearly.

Figure 13: No production rights are available in Developer edition.

Thus you should not consider this to be used with production data. You can, until a time when it is allowed, you should stick with Windows platform and download Express edition. It has more than enough space for small projects.

4. Should you use it?

Finally, if you are a learner like me, if you want to try something new out, then yes of course go ahead and try it out. You can install a Ubuntu on a VirtualBox to try this thing out if you’d like.

If you find something new, message me and we can chat on that. 🙂

Is using ‘using’ block really helpful?

Introduction and Background

So, it all began on the Facebook when I was posting a status (using Twitter) about a statement that I was feeling very bad that .NET team had left out the “Close” function while designing their .NET Core framework. At first I thought maybe everything was “managed” underground until I came up to an exception telling me that the file was already being used. The code that I was using was something like this,

if(!File.Exists("path")) { File.Create("path").Close(); }

However, “Close” was not defined and I double checked against .NET Core reference documentations too, and they suggested that this was not available in .NET Core framework. So I had to use other end… Long story short, it all went up like this,

I am unable to understand why was “Close” function removed from FileStream. It can be handy guys, @dotnet.

Then, Vincent came up with the idea of saying that “Close” was removed so that we all can use “using” blocks, which are much better in many cases.

You don’t need that. It’s handier if you just put any resource that eats resources within the “using block”. 🙂

Me:

How does using, “using (var obj = File.Create()) { }” make the code handier?

I was talking about this, “File.Create().Close();”

Now, instead of this, we have to flush the stream, or perform a flush etc. But I really do love the “using block” suggestion, I try to use it as much as I can. Sometimes, that doesn’t play fair. 😉

He:

Handier because I don’t have to explicitly call out the “Close()” function. Depends on the developer’s preference, but to me, I find “using (var obj = File.Create()) { }” handier and sexier to look at rather than the plain and flat “File.Create().Close();”. Also, it’s a best practice to “always” use the using block when dealing with objects that implements IDisposable to ensure that objects are properly closed and disposed when you’re done with it. 😉

As soon as you leave the using block’s scope, the stream is closed and disposed. The using block calls the Close() function under the hood, and the Close() calls the Flush(), so you should not need to call it manually.

Me:

I will go with LINQPad to see which one is better. Will let you know.

So, now I am here, and I am going to share what I find in the LINQPad. The fact is that I have always had faith in the code that works fast and provides a better performance. He is an ASP.NET MVP on Microsoft and can be forgiven for the fact that web developers are trained on multi-core CPUs and multi-deca-giga-bytes of RAMs so they use the code that looks cleaner but… He missed the C# bytecode factor here. I am going to use LINQPad to find out the underlying modifications that can be done to find out a few things.

Special thanks to Vincent: Since a few days I was out of topics to write on, Vincent you gave me one and I am going to write on top of that debate that we had.

Notice: I also prefer using the “using” block in almost every case. Looks handier, but the following code block doesn’t look handier at all,

using (var obj = File.Create("path")) { }

And this is how it began…

Exploring the “using” and simple “Close” calls

LINQPad is a great software to try out the C# (or .NET framework) code and see how it works natively, it lets you see the native bytecode of ,NET framework and also lets you perform and check the tree diagrams of the code. The two types that we are interested in are, “using” statement of .NET framework and the simple “Close” calls that are made to the objects to close their streams.

I used a Stopwatch object to calculate the time taken by the program to execute each task, then I match the results of each of the program with each other to find out which one went fast. Looking at the code of them both, it looks the thousand-feet high view of them both looks the same,

// The using block
using (var obj = File.Create("path")) { }

// The clock method
File.Create("path").Close();

They both the same, however, their intermediate code shows something else.

// IL Code for "using" block
IL_0000: nop 
IL_0001: ldstr "F:/File.txt"
IL_0006: call System.IO.File.Create
IL_000B: stloc.0 // obj
IL_000C: nop 
IL_000D: nop 
IL_000E: leave.s IL_001B
IL_0010: ldloc.0 // obj
IL_0011: brfalse.s IL_001A
IL_0013: ldloc.0 // obj
IL_0014: callvirt System.IDisposable.Dispose
IL_0019: nop 
IL_001A: endfinally 
IL_001B: ret 

// IL Code for the close function
IL_0000: nop 
IL_0001: ldstr "F:/File.txt"
IL_0006: call System.IO.File.Create
IL_000B: callvirt System.IO.Stream.Close
IL_0010: nop 
IL_0011: ret

Oh-my-might-no! There is no way, “using” block could have ever won with all of that extra intermediate code for the .NET VM to execute before exiting. The time taken by these commands was also tested and for that I used the native Stopwatch object to calculate the “ticks” used, instead of the time in milliseconds by each of the call. So my code in the LINQPad looked like this,

void Main()
{
   Stopwatch watch = new Stopwatch();
   watch.Start();
   using (var obj = File.Create("F:/file.txt")) { }
   watch.Stop();
   Console.WriteLine($"Time required for 'using' was {watch.ElapsedTicks}.");
 
   watch.Reset();
   watch.Start();
   File.Create("F:/file.txt").Close();
   watch.Stop();
   Console.WriteLine($"Time required for 'close' was {watch.ElapsedTicks}.");
}

The execution of the above program always results in a win for the “Close” function call. In sometimes it was a close result, but still “Close” function had a win over the “using” statement. The results are shown the images below,

The same executed, produced different results, there are many factors to this and it can be forgiven for all of them,

1. Operating system might put a break to the program for its own processing.
2. Program might not be ready for processing.
3. Etc. etc. etc.

There are many reasons. For example, have a look at the last image, the time taken was 609 ticks. Which also includes the ticks taken by other programs. The stopwatch was running ever since, and that is what caused the stopwatch to keep tracking the ticks. But in any case, “using” statement was not a better solution from a low level code side.

Final words

Although I also recommend using the “using” block statement in C# programs, but there is a condition where you should consider using one over other. For example, in this condition, we see that implementing one over the other has no benefit at all, but just a matter of personal interest and like. Although I totally agree to Vincent where he mentions that “using” block is helpful, but in other cases. In this case, adding a Close call is a cleaner (IMO) way of writing the program as compared to the other one.

At the end, it is all in the hands of the writer… Select the one you prefer.

A quick startup using .NET Core on Linux

I know you may be thinking… This post is another rhetoric post by this guy, yes it is. 🙂 .NET Core is another product that I like, the first one being, .NET framework itself. It was last year when .NET Core got started and Microsoft said they are going to release the source code as a part of their open source environment and love. By following the open source project environment and ethics, Microsoft has been working very hard in bringing global developers toward their environments, platforms and services. For example, .NET framework works on Windows, C# language is used to build Windows Store applications, C# is also the primary language in Microsoft’s web application development framework, ASP.NET and much more. The online cloud service of Microsoft is also programmed in C#; primarily. These things are interrelated to each other. Thus, when Microsoft brings all of this as an open source project, things start to get a lot better!

Everyone knows about the background of .NET Core, if you don’t know, I recommend that you read the blog post on Microsoft, Introducing .NET Core. The(ir) basic idea was to provide a framework that would work with any platform, any application type and any framework to be targeted.

Introduction and Background

In this quick post, I will walk you through getting started with .NET Core, installing it on a Linux machine and I will also give my views as to why install .NET Core on a Linux machine instead of Windows machine, I will then walk you through different steps of .NET Core programming and how you can use terminal based environment to perform multiple tasks. But first things first.

I am sure you have heard of .NET Core and other of the cool stuff that Microsoft has been releasing these years, From all of these services the ones that I like are:

1. C# 6
   • In my own opinion, I think the language looks cleaner now. These sugar-coated features make the language easier to write too. If you haven’t yet read, please read my previous blog post at, Experimenting with C# 6’s new features.
2. .NET Core
   • Of course, who wouldn’t love to use .NET on other platforms.
3. Xamarin acquisition
   • I’m going to try this one out tonight. Fingers crossed.
4. Rest are all just “usual” stuff around.

In this post I am going to talk about .NET Core on Linux because I have already talked about the C# stuff.

Figure 1: .NET Core is a cross-platform programming framework by Microsoft.

Why Linux for .NET Core?

Before I dive any deeper, as I had said, I will give you a few of my considerations for using .NET Core on Linux and not on Windows (yet!) and they are as following. You don’t have to take them seriously or to always consider them, they are just my views and my opinions, you are free to have your own.

1. .NET Core is not yet complete

It would take a while before .NET gets released as a public stable version. Until then, using this bleeding edge technology on your own machines won’t be a good idea and someday sooner you will consider removing the binaries. In such cases, it is always better to use it in the virtual machine somewhere. I have set up a few Linux (Ubuntu-based) virtual machines for my development purposes, and I recommend that you go the same.

1. Install VirtualBox (or any other virtualization software that you prefer; I like VirtualBox for its simplicity).
2. Set up an Ubuntu environment.
   • Remember to use Ubuntu 14.04. Later ones are not yet supported yet.
3. Install the .NET Core on that machine.

If something goes wrong. You can easily revert back where you want to. If the code plays dirty, you don’t have to worry about your data, or your machine at all.

2. Everything is command-line

Windows OS is not your OS if you like command-line interfaces. I am waiting for the BASH language to be introduced in Windows as in Ubuntu, until then, I am not going to use anything that requires a command-line interface to be used on my Windows environment. In Linux, however, everything almost has a command-line interface and since the .NET Core is a command-based program by Microsoft that is why I have enjoyed using it on Linux as compared to Windows.

Besides, on command-line interface, creating, building and running a .NET Core project is as simple as 1… 2… 3. You’ll see how, in the sections below. 🙂

3. I don’t use Mac

Besides these points, the only valid point left is then why shouldn’t we use Mac OS for .NET Core is because I don’t use it. You are free to use Mac OS for .NET Core development too. .NET Core does support it, its just that I don’t support that development environment. 😀

Installation of .NET Core

Although it is intended that soon, the command would be as simple as:

$ sudo apt-get install dotnet

Same command is used on Mac OS X and other operating systems other than Ubuntu and Debian derivatives. But until the .NET Core is in development process that is not going to happen. Until then, there are other steps that you can perform to install the .NET Core on your own machine. I’d like to skip this part and let Microsoft give you the steps to install the framework.

Installation procedure of .NET Core on multiple platforms.

After this step, do remember to make sure that the platform has been installed successfully. In almost any environment, you can run the following command to get the success message.

> dotnet --help

If .NET is installed, it would simply show the version and other help material on the screen. Otherwise, you may want to make sure that that procedure did not incur any problems during the installation of the packages. Before I get started, I want to show you the help material provided with “dotnet” command,

afzaal@afzaal-VirtualBox:~/Projects/Sample$ dotnet --help
.NET Command Line Tools (1.0.0-preview1-002702)
Usage: dotnet [common-options] [command] [arguments]

Arguments:
 [command]      The command to execute
 [arguments]    Arguments to pass to the command

Common Options (passed before the command):
 -v|--verbose   Enable verbose output
 --version      Display .NET CLI Version Number
 --info         Display .NET CLI Info

Common Commands:
 new           Initialize a basic .NET project
 restore       Restore dependencies specified in the .NET project
 build         Builds a .NET project
 publish       Publishes a .NET project for deployment (including the runtime)
 run           Compiles and immediately executes a .NET project
 test          Runs unit tests using the test runner specified in the project
 pack          Creates a NuGet package

So, you get the point that we are going to look deeper into the commands that dotnet provides us with.

1. Creating a package
2. Restoring the package
3. Running the package
   • Build and Run both work, run would execute, build would just build the project. That was easy.
4. Packaging the package

I will slice the stuff down to make it even more clearer and simpler to understand. One thing that you may have figured is that the option to compile the project natively is not provided as an explicit command in this set of options. As far as I can think is that this support has been removed until further notice. Until then, you need to pass a framework type to compile and build against.

Using .NET Core on Linux

Although the procedure on both of the environments is similar and alike. I am going to show you the procedure in Ubuntu. Plus, I will be explaining the purpose of these commands and multiple options that .NET provides you with. I don’t want you feel lonely here, because most of the paragraphs here would be for Microsoft team working on .NET project, so I would be providing a few suggestions for the team too. But, don’t worry, I’ll make sure the content seems to be and remain on-topic.

1. Creating a new project

I agree that the framework development is not yet near releasing and so I think I should consider passing on my own suggestions for the project too. At the moment, .NET Core supports creating a new project in the directory and uses the name of the directory as the default name (if at all required). Beginners in .NET Core are only aware of the commands that come right after the “dotnet”. However, there are other parameters that collect a few more parameters and optional values such as:

1. Type of project.
   • Executable
     • At the moment, .NET only generates DLL files as output. Console is the default.
   • Dynamic-link library
2. Language to be used for programming.

To create a new project, at the moment you just have to execute the following command:

$ dotnet new

In my own opinion, if you are just learning, this is enough for you. However, if you execute the following command you will get an idea of how you can modify the way project is being created and how it can be used to modify the project itself, including the programming language being used.

$ dotnet new --help
.NET Initializer

Usage: dotnet new [options]

Options:
 -h|--help Show help information
 -l|--lang <LANGUAGE> Language of project [C#|F#]
 -t|--type <TYPE> Type of project

Options are optional. However, you can pass those values if you want to create a project with a different programming language such as F#. You can also change the type, currently however, Console applications are only supported.

I already had a directory set up for my sample testing,

Figure 2: Sample directory open. 

So, I just created the project here. I didn’t mess around with anything at all, you can see that the .NET itself creates the files.

Figure 3: Creating the project in the same directory where we were.

Excuse the fact that I created an F# project. I did that so that I can show that I can pass the language to be used in the project too. I removed that, and instead created a C# program-based project. This is a minimal Console application.

In .NET Core applications, every project contains:

1. A program’s source code.
   • If you were to create an F# project. Then the program would be written in F# language and in case of default settings. The program is a C# language program.
2. A project.json file.
   • This file contains the settings for the project and dependencies that are to be maintained in the project for building the project.

However, once you are going to run you need to build the project and that is what we are going to do in the next steps.

2. Restoring the project

We didn’t delete the project. This simply means that the project needs to be restored and the dependencies need to be resolved before we can actually build to run the project. This can be done using the following command,

$ dotnet restore

Note: Make sure you are in the working directory where the project was created.

This command does the job of restoring the packages. If you try to build the project before restoring the dependencies, you are going to get the error message of:

Project {name} does not have a lock file.

.NET framework uses the lock file to look for the dependencies that a project requires and then starts the building and compilation process. Which means, this file is required before your project can be executed to ensure “it can execute”.

After this command gets executed, you will get another file in the project directory.

Figure 4: Project.lock.json file is now available in the project directory.

And so finally, you can continue to building the project and to running it on your own machine with the default settings and setup.

3. Building the project

As I have already mentioned above, the native compilation support has been removed from the toolchain and I think Ubuntu developers may have to wait for a while and this may only be supported on Windows environment until then. However, we can somehow still execute the project as we would and we can perform other options too, such as publishing and NuGet package creation.

You can build a project using the following command,

$ dotnet build

Remember that you need to have restored the project once. Build command would do the following things for you:

1. It would build the project for you.
2. It would create the output directories.
   • However, as I am going to talk about this later, you can change the directories where the outputs are saved.
3. It would prompt if there are any errors while building the project.

We have seen the way previous commands worked, so let’s slice this one into bits too. This command, too, supports manipulation. It provides you with optional flags such as:

1. Framework to target.
2. Directory to use for output binaries.
3. Runtime to use.
4. Configuration etc.

This way, you can automate the process of building by passing the parameters to the dotnet script.

4. Deploying the project

Instead of using the term running the project, I think it would be better if I could say deploying the project. One way or the other, running project is also deployed on the machine before it can run. First of all, the project I would show to be running, later I will show how to create NuGet packages.

To run the project, once you have built the project or not, you can just execute the following command:

$ dotnet run

This command also builds the project if the project is not yet built. Now, if I execute that command on my directory where the project resides, the output is something like this on my Ubuntu,

Figure 5: Project output in terminal.

As seen, the project works and displays the message of, “Hello World!” on screen in terminal. This is a console project and a simple project with a console output command in C# only. That is why the program works this way.

Creating NuGet packages

Besides this, I would like to share how you can create the NuGet package from this project using the terminal. NuGet packages have been in the scene since a very long time and they were previously very easy to create in Visual Studio environment. Process is even simpler in this framework of programming. You just have to execute the following command:

$ dotnet pack

This command packs the project in a NuGet package. I would like to show you the output that it generates so that you can understand how it is doing everything.

afzaal@afzaal-VirtualBox:~/Projects/Sample$ dotnet pack
Project Sample (.NETCoreApp,Version=v1.0) was previously compiled. 
Skipping compilation.
Producing nuget package "Sample.1.0.0" for Sample
Sample -> /home/afzaal/Projects/Sample/bin/Debug/Sample.1.0.0.nupkg
Producing nuget package "Sample.1.0.0.symbols" for Sample
Sample -> /home/afzaal/Projects/Sample/bin/Debug/Sample.1.0.0.symbols.nupkg

It builds the project first, if the project was built then it skips that process. Once that has been done it create a new package and simply generates the file that can be published on the galleries. NuGet package management command allows you to perform some other functions too, such as updating the version number itself, it also allows you to specify framework etc. For more, have a look at the help output for this command,

afzaal@afzaal-VirtualBox:~/Projects/Sample$ dotnet pack --help
.NET Packager

Usage: dotnet pack [arguments] [options]

Arguments:
 <PROJECT> The project to compile, defaults to the current directory. 
 Can be a path to a project.json or a project directory

Options:
 -h|--help Show help information
 -o|--output <OUTPUT_DIR> Directory in which to place outputs
 --no-build Do not build project before packing
 -b|--build-base-path <OUTPUT_DIR> Directory in which to place temporary build outputs
 -c|--configuration <CONFIGURATION> Configuration under which to build
 --version-suffix <VERSION_SUFFIX> Defines what `*` should be replaced with in version 
  field in project.json

See the final one, where it shows the version suffix. It can be used to update the version based on the build version and so on. There is also a setting, which allows you modify the way building process updates the version count. This is a widely used method for changing the version number based on the build that produced the binary outputs.

The NuGet package file was saved in the default output directory.

Figure 6: NuGet package in the default output directory.

Rest is easy, you can just upload the package from here to the NuGet galleries.

Final words

Finally, I was thinking I should publish a minimal ebook about this guide. The content was getting longer and longer and I was getting tired and tired, however since this gave me an idea about many things I think I can write a comparison of .NET Core on Windows and Linux and I think I have enough time to do that.

Secondly, there are few suggestions for end users that I want to make.

1. Do not use .NET Core for commercial software. It is going to change sooner,
2. .NET Core is a bleeding edge technology and well, since there is no documentation, you are going to waste a lot of time in learning and asking questions. That is why, if you are considering to learn .NET framework, then learn the .NET framework and not .NET Core. .NET framework has a great amount of good resources, articles, tips and tutorials.
3. If you want cross-platform features and great support like .NET framework, my recommendation is Mono Project over .NET Core maybe because it is yet not mature.

I have a few feedback words on the framework itself.

1. It is going great. Period.
2. Since this is a cross-platform framework, features must not be available Windows-only such as that “dotnet compile –native” one. They must be made available to every platform.

At last, the framework is a great one to write programs for. I enjoyed programming for .NET Core because it doesn’t require much effort. Plus, the benefit of multiple programming languages is still there, Besides, Visual Studio Code is also a great IDE to be used and the C# extension makes it even better. I will be writing a lot about these features these days since I am free from all of the academics stuff these days. 🙂

See you in the next post.

Highlighting the faces in uploaded image in ASP.NET web applications

Introduction and Background

Previously, I was thinking we can find the faces in the uploaded image, so why not create a small module that automatically finds the faces and renders them when we want to load the images on our web pages. That was a pretty easy task but I would love to share what and how I did it. The entire procedure may look a bit complex, but trust me it is really very simple and straight-forward. However, you may be required to know about a few framework forehand as I won’t be covering most of the in-depth stuff of that scenario — such as computer vision, which is used to perform actions such as face detection.

In this post, you will learn the basics of many things that range from:

1. Performing computer vision operations — most basic one, finding the faces in the images.
2. Sending and receiving content from the web server based on the image data uploaded.
3. Using the canvas HTML element to render the results.

I won’t be guiding you throughout each and everything of the computer vision, or the processes that are required to perform the facial detection in the images, for that i would like to ask you to go and read this post of mine, Facial biometric authentication on your connected devices. In this post, I’ll cover the basics of how to detect the faces in ASP.NET web application, how to pass the characters of the faces in the images, how to use those properties and to render the faces on the image in the canvas.

Making the web app face-aware

There are two steps that we need to perform in order to make our web applications face aware and to determine whether there is a face in the images that are to be uploaded or not. There are many uses, and I will enlist a few of them in the final words section below. The first step is to configure our web application to be able to consume the image and then render the image for processing. Our image processing toolkit would allow us to find the faces, and the locations of our faces. This part would then forward the request to the client-side, where our client itself would render the face locations on the images.

In this sample, I am going to use a canvas element to draw objects, whereas this can be done using multiple div containers to contain span elements and they can be rendered over the actual image to show the face boxes with their positions set to absolute.

First of all, let us program the ASP.NET web application to get the image, process the image, find the faces and generate the response to be collected on the client-side.

Programming file processing part

On the server-side, we would preferably use the Emgu CV library. This library has been of a great usage in the C# wrappers list of OpenCV library. I will be using the same library, to program the face detectors in ASP.NET. The benefits are:

1. It is a very light-weight library.
2. The entire processing can take less than a second or two, and the views would be generated in a second later.
3. It is better than most of other computer vision libraries; as it is based on OpenCV.

First of all, we would need to create a new controller in our web application that would handle the requests for this purpose, we would later add the POST method handler to the controller action to upload and process the image. You can create any controller, I used the name, “FindFacesController” for this controller in my own application. To create a new Controller, follow: Right click Controllers folder → Select Add → Select Controller…, to add a new controller. Add the name to it as you like and then proceed. By default, this controller is given an action, Index and a folder with the same name is created in the Views folder. First of all, open the Views folder to add the HTML content for which we would later write the backend part. In this example project, we need to use an HTML form, where users would be able to upload the files to the servers for processing.

The following HTML snippet would do this,

<form method="post" enctype="multipart/form-data" id="form">
  <input type="file" name="image" id="image" onchange="this.form.submit()" />
</form>

You can see that this HTML form is enough in itself. There is a special event handler attached to this input element, which would cause the form to automatically submit once the user selects the image. That is because we only want to process one image at a time. I could have written a standalone function, but that would have made no sense and this inline function call is a better way to do this.

Now for the ASP.NET part, I will be using the HttpMethod property of the Request to determine if the request was to upload the image or to just load the page.

if(Request.HttpMethod == "POST") {
   // Image upload code here.
}

Now before I actually write the code I want to show and explain what we want to do in this example. The steps to be performed are as below:

1. We need to save the image that was uploaded in the request.
2. We would then get the file that was uploaded, and process that image using Emgu CV.
3. We would get the locations of the faces in the image and then serialize them to JSON string using Json.NET library.
4. Later part would be taken care of on the client-side using JavaScript code.

Before I actually write the code, let me first show you the helper objects that I had created. I needed two helper objects, one for storing the location of the faces and other to perform the facial detection in the images.

public class Location
{
    public double X { get; set; }
    public double Y { get; set; }
    public double Width { get; set; }
    public double Height { get; set; }
}

// Face detector helper object
public class FaceDetector
{
    public static List<Rectangle> DetectFaces(Mat image)
    {
        List<Rectangle> faces = new List<Rectangle>();
        var facesCascade = HttpContext.Current.Server.MapPath("~/haarcascade_frontalface_default.xml");
        using (CascadeClassifier face = new CascadeClassifier(facesCascade))
        {
            using (UMat ugray = new UMat())
            {
                CvInvoke.CvtColor(image, ugray, Emgu.CV.CvEnum.ColorConversion.Bgr2Gray);

                //normalizes brightness and increases contrast of the image
                CvInvoke.EqualizeHist(ugray, ugray);

                //Detect the faces from the gray scale image and store the locations as rectangle
                //The first dimensional is the channel
                //The second dimension is the index of the rectangle in the specific channel
                Rectangle[] facesDetected = face.DetectMultiScale(
                                                ugray,
                                                1.1,
                                                10,
                                                new Size(20, 20));

                faces.AddRange(facesDetected);
            }
        }
        return faces;
    }
}

These two objects would be used, one for the processing and other for the client-side code to render the boxes on the faces. The action code that I used for this is as below:

public ActionResult Index()
{
    if (Request.HttpMethod == "POST")
    {
         ViewBag.ImageProcessed = true;
         // Try to process the image.
         if (Request.Files.Count > 0)
         {
             // There will be just one file.
             var file = Request.Files[0];

             var fileName = Guid.NewGuid().ToString() + ".jpg";
             file.SaveAs(Server.MapPath("~/Images/" + fileName));

             // Load the saved image, for native processing using Emgu CV.
             var bitmap = new Bitmap(Server.MapPath("~/Images/" + fileName));

             var faces = FaceDetector.DetectFaces(new Image<Bgr, byte>(bitmap).Mat);

             // If faces where found.
             if (faces.Count > 0)
             {
                 ViewBag.FacesDetected = true;
                 ViewBag.FaceCount = faces.Count;

                 var positions = new List<Location>();
                 foreach (var face in faces)
                 {
                     // Add the positions.
                     positions.Add(new Location
                     {
                          X = face.X,
                          Y = face.Y,
                          Width = face.Width,
                          Height = face.Height
                     });
                 }

                 ViewBag.FacePositions = JsonConvert.SerializeObject(positions);
            }

            ViewBag.ImageUrl = fileName;
        }
    }
    return View();
}

The code above does entire processing of the images that we upload to the server. This code is responsible for processing the images, finding and detecting the faces and then returning the results for the views to be rendered in HTML.

Programming client-side canvas elements

You can create a sense of opening a modal popup to show the faces in the images. I used the canvas element on the page itself, because I just wanted to demonstrate the usage of this coding technique. As we have seen, the controller action would generate a few ViewBag properties that we can later use in the HTML content to render the results based on our previous actions.

The View content is as following,

@if (ViewBag.ImageProcessed == true)
{
    // Show the image.
    if (ViewBag.FacesDetected == true)
    {
        // Show the image here.
        <img src="~/Images/@ViewBag.ImageUrl" alt="Image" id="imageElement" style="display: none; height: 0; width: 0;" />

        <p><b>@ViewBag.FaceCount</b> @if (ViewBag.FaceCount == 1) { <text><b>face</b> was</text> } else { <text><b>faces</b> were</text> } detected in the following image.</p>
        <p>A <code>canvas</code> element is being used to render the image and then rectangles are being drawn on the top of that canvas to highlight the faces in the image.</p>

        <canvas id="faceCanvas"></canvas>

        <!-- HTML content has been loaded, run the script now. -->
        
            // Get the canvas.
            var canvas = document.getElementById("faceCanvas");
            var img = document.getElementById("imageElement");
            canvas.height = img.height;
            canvas.width = img.width;

            var myCanvas = canvas.getContext("2d");
            myCanvas.drawImage(img, 0, 0);

            @if(ViewBag.ImageProcessed == true && ViewBag.FacesDetected == true)
            {
            
            img.style.display = "none";
            var facesFound = true;
            var facePositions = JSON.parse(JSON.stringify(@Html.Raw(ViewBag.FacePositions)));
            
            }

            if(facesFound) {
                // Move forward.
                for (face in facePositions) {
                    // Draw the face.
                    myCanvas.lineWidth = 2;
                    myCanvas.strokeStyle = selectColor(face);

                    console.log(selectColor(face));
                    myCanvas.strokeRect(
                                 facePositions[face]["X"],
                                 facePositions[face]["Y"],
                                 facePositions[face]["Width"],
                                 facePositions[face]["Height"]
                             );
               }
           }

           function selectColor(iteration) {
               if (iteration == 0) { iteration = Math.floor(Math.random()); }

               var step = 42.5;
               var randomNumber = Math.floor(Math.random() * 3);

               // Select the colors.
               var red = Math.floor((step * iteration * Math.floor(Math.random() * 3)) % 255);
               var green = Math.floor((step * iteration * Math.floor(Math.random() * 3)) % 255);
               var blue = Math.floor((step * iteration * Math.floor(Math.random() * 3)) % 255);

               // Change the values of rgb, randomly.
               switch (randomNumber) {
                   case 0: red = 0; break;
                   case 1: green = 0; break;
                   case 2: blue = 0; break;
               }

               // Return the string.
               var rgbString = "rgb(" + red + ", " + green + " ," + blue + ")";
               return rgbString;
           }
        
    }
    else
    {
        <p>No faces were found in the following image.</p>

        // Show the image here.
        <img src="~/Images/@ViewBag.ImageUrl" alt="Image" id="imageElement" />
    }
}

This code is the client-side code and would be executed only if there is an upload of image previously. Now let us review what our application is capable of doing at the moment.

Running the application for testing

Since we have developed the application, now it is time that we actually run the application to see if that works as expected. The following are the results generated of multiple images that were passed to the server.

The above image shows the default HTML page that is shown to the users when they visit the page for the first time. Then they will upload the image, and application would process the content of the image that was uploaded. Following images show the results of those images.

I uploaded my image, it found my face and as shown above in bold text, “1 face was detected…”. It also renders the box around the area where the face was detected.

Article would have never been complete, without Eminem being a part of it! 🙂 Love this guy.

Secondly, I wanted to show how this application processed multiple faces. On the top, see that it shows “5 faces were detected…” and it renders 5 boxes around the areas where faces were detected. I also seem to like the photo, as I am a fan of Batman myself.

This image shows what happens if the image does not contain a detected face (by detected, there are many possibilities where a face might not be detected, such as having hairs, wearing glasses etc.) In this image I just used the three logos of companies and the system told me there were no faces in the image. It also rendered the image, but no boxes were made since there were no faces in the image.

Final words

This was it for this post. This method is useful in many facial detection software applications, many areas where you want the users to upload a photo of their faces, not just some photo of a scenery etc. This is an ASP,NET web application project, which means that you can use this code in your own web applications too. The library usage is also very simple and straight-forward as you have already seen in the article above.

There are other uses, such as in the cases where you want to perform analysis of peoples’ faces to detect their emotions, locations and other parameters. You can first of all perform this action to determine if there are faces in the images or not.

From zero to hero in JSON with C#

Introduction and Background

I have been reading many posts and articles about JSON and C# where every article tries to clarify the purpose of either one thing, or the other thing: JSON or C# libraries. I want to cover both of these technologies in one post so that if you have no idea of JavaScript Object Notation (JSON), and the C# libraries available for processing and parsing the JSON files you can understand these two concepts fully. I will try my best to explain each and every concept in these two frameworks and I will also try to publish the article on C# Corner and to share an offline copy of this post as an eBook, so excuse me if you find me sliding through different writing formats because I have to stick to both writing styles in order to qualify this post as an article and as a miniature guide.

When I started to do a bit of programming, I knew there were many data-interchange formats, serialization and deserialization techniques and how objects can be stored including their states in the disk to fetch the same data back for further processing and further working on the same objects that you just left while you were going outside. Some of these techniques are tough to be handled and understood while others are pretty much framework-oriented. Then comes JSON into the image, JSON provides you with a very familiar and simple interface for programming the serialization and deserialization of the objects on runtime so that their states can be stored for later use. And we are going to study JSON notation of data-interchange and how we can use this format in C# projects for our applications.

What is JSON?

I remember when I was starting to learn programming there was this something called, Extensible markup language, or as some of us know it as, XML. XML was used to convert the runtime data of the objects or the program states or the configuration settings into a storable string notation. These strings were human-readable. Programmers could even modify these values when they needed to, added more values or removed the values they didn’t want to see in the data.

Introduction of XML

For a really long time and even today, XML is being used as the format for data-interchange. Many protocols for communication are built on the top of XML, most notably SOAP protocol. XML didn’t even power a few of the protocols, it even kick-started many of the most widely known and used markup languages, of which HTML and XAML are the ones that most of you are already familiar with.

Figure 1: XML file icon.

History has it, XML has been of a great use to many programmers for building applications that share the data across multiple machines. The world wide web started with the pages written in a much XML-oriented way, markup language called, HTML.

The purpose of XML entirely was to design the documents in plain-text that can be human-readable and can be used by the machines to define the state of applications, program or interfaces.

1. State of applications: You can store the object states, which can be loaded later for further processing of the data. This would allow you to maintain the states of the applications too.
2. Program: XML can be used to define the configuration of the programs when they start up. Microsoft has been using web.config and machine.config files to define how a program would start. Programmers and developers can easily modify the files as they needed them to. This would alter the design of the way program starts.
3. Interfaces: HTML is being used to define how the user-interface would look like. Windows Presentation Foundation uses XAML as the major language for designing the interfaces. Android supports XML-based markup language for defining the UI controls.

<?xml version="1.0" encoding="UTF-8"?>

Empty XML documents are not meant to contain any blank object or document tree. They can be omitted.

This is not it. XML is much more than this, WCF, for example supports SOAP communication. Which means that you can download and upload the data in XML format. ASP.NET Web API supports data transfer in the form of XML documents.

Usage of XML

I want to show you how XML is used, then why shouldn’t I used something that comes from a real-world example. RSS for example, uses XML-based documents for delivery of feeds to the clients. I am using the same technology feature on my blog to deliver the blog posts to readers and other communities. The basic XML document for a single post would look like this,

<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0"
    xmlns:atom="http://www.w3.org/2005/Atom"
    xmlns:media="http://search.yahoo.com/mrss/">

<channel>
    <title>Learn the basics of the Web and App Development</title>
    <atom:link href="https://basicsofwebdevelopment.wordpress.com/feed/" rel="self" type="application/rss+xml" /> 
    <link>https://basicsofwebdevelopment.wordpress.com</link>
    <description>The basics about the Web Standards will be posted on my blog. Love it? Share it! Found an error, ask me to edit the post! :)</description>
    <lastBuildDate>Fri, 03 Jun 2016 09:48:29 +0000</lastBuildDate>
    <language>en</language>
    <generator>http://wordpress.com/</generator>
    <cloud domain='basicsofwebdevelopment.wordpress.com' port='80' path='/?rsscloud=notify' registerProcedure='' protocol='http-post' />
    <image>
         <url>https://s2.wp.com/i/buttonw-com.png</url>
         <title>Learn the basics of the Web and App Development</title>
         <link>https://basicsofwebdevelopment.wordpress.com</link>
    </image>
    <atom:link rel="search" type="application/opensearchdescription+xml" href="https://basicsofwebdevelopment.wordpress.com/osd.xml" title="Learn the basics of the Web and App Development" />
    <atom:link rel='hub' href='https://basicsofwebdevelopment.wordpress.com/?pushpress=hub'/>
    <item>
        <title>Hashing passwords in .NET Core with tips</title>
        <link>https://basicsofwebdevelopment.wordpress.com/2016/06/03/hashing-passwords-in-net-core-with-tips/</link>
        <comments>https://basicsofwebdevelopment.wordpress.com/2016/06/03/hashing-passwords-in-net-core-with-tips/#respond</comments>
        <pubDate>Fri, 03 Jun 2016 08:42:49 +0000</pubDate>
        <dc:creator><![CDATA[Afzaal Ahmad Zeeshan]]></dc:creator>
        <category><![CDATA[Beginners]]></category>
        <category><![CDATA[C# (C-Sharp)]]></category>
        <guid isPermaLink="false">https://basicsofwebdevelopment.wordpress.com/?p=1313</guid>
        <description>
            <![CDATA[Previously I had written a few stuff for .NET framework and how to implement basic security concepts on your applications that are working in .NET environment. In this post I want to walk you to implement the same security concepts in your applications that are based on the .NET Core framework. As always there will be […]<img alt="" border="0" src="https://pixel.wp.com/b.gif?host=basicsofwebdevelopment.wordpress.com&blog=59372306&post=1313&subd=basicsofwebdevelopment&ref=&feed=1" width="1" height="1" />]]>
        </description>
    </item>
</channel>
</rss>

Of course I snipped out most of the part, but you get the point of XML here. This data can be read by humans themselves, and if the machine is set to parse this data it can provide us with runtime association of data with the objects. In a much similar manner, we can share the data from one machine to another by serializing and deserializing the objects.

What is the need of JSON, then?

JSON comes into the frame back in 1996 or around that time. The purpose of XML and JSON is similar: Data-interchange among multiple devices, networks and applications. However, the language syntax is very much similar to what C, C++, Java and C# programmers have been using for their regular day “object-oriented programming“; pardon me C programmers. The language syntax is very similar to what JavaScript uses for the notation of objects. JSON provides a much compact format for the documents for storing the data. JSON data, as we will see in this guide, is much shorter as compared to XML and in many ways can be (and should be…) used on the network-based applications where each byte can be a bottleneck to your application’s performance and efficiency. I wanted to take this time to disgust XML, but I think your mind will consider my words as personal and bias views. So, first I will talk about JSON itself how it is structured and then I will talk about using the time to show the difference between JSON and XML and which one to prefer.

JSON format and specifications were shared publicly as per ECMA-404. The document guides the developers to find their APIs in such a way that they work as per the teachings of the standard. API developers, programmers, serialization/deserialization software developers can get much help from the documentation in understanding how to define their programs to parse and stringify the JSON content.

Structure of JSON

JSON is an open-standards document format for human-readable and machine-understandable serialization and deserialization of data. Simply, it is used for data-interchange. The benefit of JSON is that it has a very compact size as compared to XML documents of the same purpose and data. JSON stores the data in the form of key/value pairs. Another benefit of JSON is (just like XML) it is language-independent. You can work with JSON data in almost any programming language that can handle string objects. Almost every programming framework that I can think of most of the programming frameworks support JSON-based data-interchange. For example, ASP.NET Web API supports JSON format data transfer to-and-from the server.

The basic structure of JSON document is very much simple. Every document in JSON must have either an object at its root, or an array. Object and array can be empty there is no need for it to contain anything in it, but there must be an object or an array.

A sample, and simple JSON document can be the following one:

{ }

What that means, is something that I am going to get into a bit later. At the moment just understand that this is a blank JSON document about any object in the application. A JSON document can contain other data in the form of key/value pairs, that are of the following types:

1. Object
2. Array
3. String; name or character.
4. Integer; numeric
5. Boolean; true or false
6. Null.

Note that JSON doesn’t support all of the JavaScript keywords, such as you cannot use “undefined” in a valid JSON schema. Nothing is going to stop you from using it in your files, but remember that valid JSON schema should not include such values. One more thing to consider is that JSON is not executable file, although it shares the same object notation but it doesn’t allow you to create variables. If you try to add a few variables to it, it would generate errors. Now I would like to share a few concepts for the valid data types in JSON and what they are and how you should use them in your own JSON data files.

JSON data types

JSON data types are the valid values that can be used in JSON files. In this section I want to clarify the values that they can hold, how you can use them in your own project data-interchange formats.

JSON Object

At the root of the JSON document, there needs to be either a JSON object or a JSON array. In JavaScript and in many other programming languages an object is denoted by curly braces; “{ }”. JSON uses the same notation for denoting the objects in the JSON file. In JSON files, objects only contain the properties that they have. JSON can use other properties, other data types (including objects) as the value for their properties. How that works, I will explain that later in this course guide, but for now just consider that each of the runtime object is mapped to one JSON object in the data file.

In the case of an object, there are properties and their values that are enclosed inside the opening and closing curly braces. These are in the form of a key/value pair. These key value sets are separated using a colon, “:” and multiple sets are separated using a comma, “,”. An example of the JSON object is as follows:

{
  "name": "Afzaal Ahmad Zeeshan",
  "age": 20
}

Even the simplest of the C#, Java or C++ programmers would understand what type these properties are going to hold. It is clear that the “name” property is of “string” type and the “age” property is of integer type.

There are however a few things that you may need to consider at the moment:

1. An object can contain any number of properties in it.
2. An object can omit the properties; being an empty object.
3. All the property names (keys) are string values. You cannot omit the quotation around the key name. It is required, otherwise JSON would claim that it was expecting a string but found undefined.
4. Key/value sets are separated by a colon character, whereas multiple sets are separated using a comma. You cannot add trailing commas in the JSON format, some of the APIs may through error. For example, JSON.parse(‘[5, ]’); would return an error.

I will demonstrate the errors in a later section because at the moment I want to show you and teach you the basics of JSON. But, I will show you how these things work.

By now the type of the JSON object is clear to you. One thing to keep in mind is that JSON object is not only meant to be used as the root of the JSON document. It is also used as a value for the properties of the object, which allows the JSON document to contain the entire data in the form of relationship with objects; only difference being that the objects are anonymous.

JSON Arrays

Like JavaScript, JSON also supports storing the objects in a sequence, series or list; what-ever you would like to put it as. Arrays are not complex structures in JSON document. They are:

1. Simple.
2. Start with a square bracket, and end on the same.
3. Can contain values in a sequence.
4. Each value is separated by a comma (not a colon).
5. Value can be of any type.

A sample JSON array would look something like this,

[ "Value 1", "Value 2" ]

You can store any type of value in the array, unlike other programming language such as C# or C++. The type of the values is not mandatory to be similar. That is something that pure C# or C++ programmers cannot fathom in the first look. But, guys, this is JavaScript. I used JSONLint service to verify this, later I will show you how it works in JavaScript.

Figure 2: JSONLint being used for verification of JSON validity.

In JavaScript, the type doesn’t need to be matched of the arrays. So, for example you can do the following thing and get away with it without anything complaining about type of the objects.

var arr = [ "Hello", 55, {} ];

So, JSON being a JavaScript-derived document format, follows the same convention. JSON leaves the idea of type casting to the programmer, because this is performed only in the context of strongly typed programming languages such as C++, C# etc. JavaScript, being weakly typed doesn’t care about the stuff at all. So, it can take any type in an array as long as it doesn’t violate other rules.

Upcoming data types are similar to what other programming languages have, such as strings, integers and boolean values. So, I will try to not-explain them as much as I have had explained these two.

JSON Strings

String typed values are the values which contain the character-type values. In many programming environments, strings are called, arrays of characters. In JavaScript, you can use either single quotes or double quotes to wrap the string values. But, in JSON specification you should always consider using double quotation. Using single quotation may work and should work in JavaScript environment but in the cases when you have to share the data over the network to a type-safe programming environment such as where C++ or C# may be used as the programming language. Then your single quotes may cause a runtime error when their parsers would try to read a string starting as a character.

In JSON, strings are similar and you have been watching strings in the previous code samples. A few common examples of string values in JSON are as following:

// Normal string
"Afzaal Ahmad Zeeshan"

// Same as above, but do not use in JSON
'Afzaal Ahmad Zeeshan'

// Escaping characters, outputs: "\"
"\"\\\"" 

// Unicode characters
"\u0123"

In the above example, you see that we can use many characters in our data. We can:

1. Build normal strings such as C# or C++ strings.
   • JSON standard forbids you from using the single quotation because you may be sending the data over to other platforms.
2. Escaping the characters is required in strings. Otherwise, the string would result in undefined behavior. You can use the similar string escaping provided in other languages such as:
   • \”
   • \\
   • \/
   • \b
   • \f
   • \n
   • \r
   • \t
   • \u-4-hex-numbers
3. Unicode characters (as specified in the last element of above list) are also supported in JSON, you can specify the Unicode character code here.

One thing to consider is that your objects’ attributes (properties) are also keyed using a string value.

{
    "key": 1234
}

The value of a property can be anything, but the key must always be a string. The strings in JSON, JavaScript, C++, C# and Java are all alike and have the same value for each of the sentence. Unicode characters are supported and need not to be escaped. For original JSON website, I got this image,

Figure 3: JSON string structure.

Thus, the strings are similar in JSON and other frameworks (or languages).

JSON Integers

Just like strings, integers are also the literal values in the JSON document that are of numeric type. They are not wrapped in quotations, if they are then they are not numeric types, instead they are of string type.

A few examples of integer values are:

// Simple one
1234

// Fractional
12.34

// Exponential
12e34

You can combine fractional and exponential too. You can also append the sign of the number (negative – or positive +) with the number itself. In JSON these types can also be used as the values. If you take a look at the example above in a few sections above, you can see that I had used the age as an integer value for my property. A few things that you should consider while working with JSON data is:

1. In exponential form, “e” and “E” are similar.
2. It must never end with “e”.
3. Number cannot be a NaN.
4. Number encoding and variable size should be considered. JavaScript and other language may differ in encoding the variable size for the numberics and may cause an overflow.

JSON Boolean

Boolean values indicate the results of a conditional operation on an expression. Such as, “let him in, if he is adult”. JSON supports storing values in their literal boolean notation. They are similar to what other programming languages have in common. They must also not be wrapped in quotation as they are literals. If a boolean value is wrapped in quotation then it is not a boolean value but instead it is a string value.

// Represents a true result
true

// Represents a false result
false

These must be written as they are because JavaScript is case-sensitive and so is JSON. You can use these values to denote the cases where other types cannot make much sense compared to what this can make, sense. For example, you can specify the gender of the object.

{
    "name": "Afzaal Ahmad Zeeshan",
    "age": 20, 
    "gender": true
}

I didn’t use “male”, instead I used “true”. On the other side I can then translate this condition to another type such as,

if(obj.gender) {
    // Male
} else {
    // Female
}

This way, other than strings and numeric values we can store boolean values. These would help us structure the document in a much simpler, cleaner and programmer-readable format.

JSON null

C based programmers understand what a null is. I have been programming in programming languages such as, C, C++, C#, Java, JavaScript and I have used this keywords where the objects do not exist. There are other programming languages such as Haskell, where this doesn’t make much sense. But, since we are just talking about JavaScript and languages like it, we know what null is. Null just represents when an object doesn’t exist in the memory. In JavaScript, this means the “intentional absence” of the object. So in JavaScript environment a null object does exist but has no value. In other languages it is the other way around; it doesn’t even exist.

It just has a single notation,

null

It is a keyword and must be typed as it is. Otherwise, JavaScript-like error would pop up, “undefined“. This can help you in sending the data which doesn’t exist currently. For example, in C# we can use this to pass the values from database who are nullable. There are nullable types in C#, which we can map to this one.  For example, the following JSON document would be mapped to the following C# object:

{
    "name": "Afzaal Ahmad Zeeshan",
    "age": null
}

C# object structure (class)

class Person {
    public string Name { get; set; }
    public int? Age { get; set; }      // Nullable integer.
}

And in the database if the field is set to be nullable, we can set it to that database record. This way, JSON can be used to notably denote the runtime objects in a plain-string-text format for data-interchange.

Examples of use

I don’t want to stretch this one any longer. JSON has been widely accepted by many companies even Microsoft. Microsoft was using the web.config file in XML format for configuration purposes of the application. However, since a while they have upgraded their systems to parse and use the settings provided in a much JSON way. JSON is very simpler and easier to handle.

Microsoft started to use JSON format to handle the settings for their Visual Studio Code product. JSON allows extension of the settings, which helps users to add their own modifications and settings to the product.

I have been publishing many articles about JSON data sources and I think, if I started to use JSON then it was a sign of success of JSON over XML. 🙂

1. Creating a “customizable” personal blog using ASP.NET
2. Understanding ASP.NET MVC using real world example, for beginners and intermediate

There are many other uses of JSON and my personal recommendation is with JSON if you can use JSON over XML. However, if you are interested in XML or are supposed to use XML such as when using SOAP protocol. Otherwise, consider using JSON.

Errors in JSON

No, these are not errors in the JSON itself, but a few errors that you may make while writing the JSON documents yourself. This is why, always consider using a library.

Trailing commas

As already mentioned above, the trailing commas in the JSON objects or arrays cause a problem. The parser may think that there is another property to come but unexpectedly hits a terminating square or curly bracket. For example the following are invalid JSON documents:

{ "k": "v",  }    // Ending at a comma

[ 123, "", ]      // Ending at a comma

These can be overcame if you:

1. First of all, write your own parsers.
2. Make them intelligent enough to know that if there is no property, they can ignore adding a property, simply.
3. If there is no more value in the array after the comma, it means the array ended at the previous token.

However, present parsers are not guaranteed to be intelligent enough so my recommendation is to ignore this.

Ending with an “e” or “E”

If you end your numbers in exponential form with a e, you are likely to get an error of undefined. You know what that means, don’t you? It is always better to end it is a proper format following the specification.

Undefined

Each property name must be a string token. In JavaScript you can do the both of the following:

var obj = { "name": "Afzaal Ahmad Zeeshan" };

// OR
var obj = { name: "Afzaal Ahmad Zeeshan" };

But in JSON you are required to follow the string-based-key-names method of creating and defining the object properties. In JSON, if you do the following you will get error,

{ 
   name: "Afzaal Ahmad Zeeshan"
}

Because, name is undefined. Parser may consider it to be a variable somewhere but JSON documents cannot be executed so there is no purpose of JavaScript variables to be there. Some libraries may render the results for your documents even if you leave your property names un-stringed. But, don’t consider everything to be server always follow the specifications.

C# side of article

To this point I hope that JSON is as simple as 1… 2… 3. for you! If not, please let me know so that I can make it even more clear. But, in this section I want to talk about using JSON in your C# projects. In this section I am going to talk about the libraries that are available in C#, or more specifically I am going to talk about JSON.NET library. I will use this library to explain how JSON can be used to save the state of the objects. How you can create a JSON file, how you can parse it to create objects on runtime and how serialization and deserialization works.

This section will be a real world section covering the methods and practices that you can use to use JSON in your own applications. I will cover most of the C# programming part in this section so that you can understand and learn how to program JSON in your .NET environment.

JSON.NET library

I am specifically just going to walk you through JSON.NET library. JSON.NET is a widely used JSON parser for .NET framework. I have been using this library for a very long time and I personally this is one of the best APIs out there for JSON parsing.

Figure 4: Json.NET comparison with other popular JSON serializers.

I will use the objects provided in this library just to demonstrate how you can parse JSON files to runtime objects, and how you can create JSON strings (serialize the objects) using the objects provided to the serializer. By the end of this post you will be able to create your own JSON-oriented-and-backed applications in .NET framework (or any framework that supports C# programming).

Creating the object for this guide

In C#, we create classes to work around with real-world objects. We can then use this library to convert the runtime structure of that object to a storable JSON document that can be used to:

1. Send over the network.
2. Save on the disk.
3. Save for loading the object in that state later.

Many other uses. The counterpart of this process is the deserialization of the objects in runtime structures from their JSON notation. First of all, I will create a sample class that we are going to use to convert to JSON format and from the JSON format.

class Person
{
    public int ID { get; set; }
    public string Name { get; set; }
    public bool Gender { get; set; }
    public DateTime DateOfBirth { get; set; }
}

This object has the following diagram.

Figure 5: Person class diagram.

Frankly speaking, this object can be created in C++, it can be created in Java and it can be created in JavaScript too. If we use JSON for serializing this object, or the number of objects that can be transmitted over the network to the peers on the networks. Since we have stringified the data in JSON notation, we now can parse the string data in other languages too. Every other programming language has a JSON parser library.

We can redefine the structures in other programming languages and then use a JSON parser library to convert this string over the network in those machines too. I am going to cover C# part of programming only.

A few things that you might want to know here before we move forward. I have used the datatype of “DateTime” because I wanted to show how derived types are converted to when they are being serialized to JSON notation. So, let’s begin the C# programming to understand the relative stuff in their C# counterparts.

Serializing the objects

In programming, serialization is the process of converting the runtime objects to a plain-text string format. In other words, it converts the object structure from memory to a format that can be stored on the disk. Serialization just translates the state of the objects, which is that it just translates the properties of the object to the format that can be used to store them for later use. You can think of it as synchronization process, where you store the current state of the objects on the disk so that you can load the data later and start your work from the state where you left it instead of starting from scratch again.

Since we are talking about JSON here, we are interested in the conversion of objects in their JSON notation for storage (serialization) and then in the upcoming section to convert the JSON document into runtime objects and data structures (deserialization). Simply, we are going to see how to convert the JSON into objects and vice versa.

To serialize the object, you need an object that holds the data in itself. The object would have a state in the application. We then call the library functions to serialize the objects in their JSON notation. Like this,

// Create the person
Person myself = new Person { 
                    ID = 123, 
                    Name = "Afzaal Ahmad Zeeshan", 
                    Gender = true, 
                    DateOfBirth = new DateTime(1995, 08, 29) 
                };

// Serialize it.
 string serializedJson = JsonConvert.SerializeObject(myself);

// Print on the screen.
 Console.WriteLine(serializedJson);

The function is called to serialize the object which (as clearly seen) return a string object. This object holds the JSON notation for the object. The output returned was like this, (yes, I formatted the JSON document for readability)

{
    "ID": 123,
    "Name": "Afzaal Ahmad Zeeshan",
    "Gender": true,
    "DateOfBirth": "1995-08-29T00:00:00"
}

We create store the data in a file, send it on the network or do what we have to. I am not going to cover that part because I think (and believe) that this is totally relative to your application design and how it is expected to work. Now, we need to understand how it happened.

The ID, Name and Gender are the types that you have already seen. However the last field was actually of type DateTime which got translated to string type in JSON. Why? The answer is simple, JSON doesn’t provide a native DateTime object to store the date and time values. Instead, they use string notation to store the date value. The string value is very much self-explanatory as to what the year is, what month and what value date has. The time part is also clearly visible.

One thing to note here is that C# and JSON can agree on using the “null” value for objects too. Thus if the name is set to a null value, JSON can support the same value of null in its own document format. In the next section, we will study how JSON is mapped to the objects.

Deserializing the JSON

In data-interchange, this is the counterpart of the serialization process. In this process, we take the JSON document and parse it the runtime object (collection). There are many libraries available that can be used for parsing purposes however I am going to talk about the same one that I had been using to demonstrate the usage in C# programming environment. The method is very simple in this case too, However, I am going to use a JSON formatted string variable to use to parse it to the object.

Note: You can use values from files, networks, web APIs and other resources from where you can get the JSON formatted document. Just for the sake of simplicity I am going to use a string variable to hold the values.

The sample JSON data can be like the following,

string data = "{\"ID\": 123,\"Name\": 
               \"Afzaal Ahmad Zeeshan\",\"Gender\": 
               true,\"DateOfBirth\": \"1995-08-29T00:00:00\"}";

I used the following code to deserialize the JSON document.

// Serialize it.
Person obj = JsonConvert.DeserializeObject<Person>(data);

// Print on the screen.
Console.WriteLine(obj.ID);

Now notice one thing here. This “DeserializeObject” function has two versions.

1. A plain non-generic version.
2. A generic version.

If you use the non-generic version, then in C# you are going to use the dynamic object creation in C# and then we will be using the properties. For example, like the code below:

dynamic obj = JsonConvert.DeserializeObject(data);

Console.WriteLine(obj.ID);

Using that dynamic keyword would allow you to bypass the compile time check and allow you to get the “ID” property at a later time. This can be handy when you don’t want to create a class and deserialize against.

However, the version that I am using at the moment is different. It uses a type-parameter that is passed as a generic parameter; angled brackets, and Json.NET deserializes the JSON document and fills up our objects. We can also have array of objects, this way instead of “convincing” the program to iterate over the collection. We can first of all have the JSON parsed as an array of objects and so on. This would help us shorten the code and to check the stuff at all.

var listOfObjects = JsonConvert.DeserializeObject<List<Person>>(data);

Notice that we are passing a “List<>” object. Library would convert the stuff into the list of the objects and we can then use the collection for iterative purposes.

Some errors

There are a few errors that I would like to raise here, which might help you in understanding how JSON works. I will update this section later as I collect more data on this topic.

Type mismatch

If you try to deserialize the JSON of one type (such as, an object) into a type where it cannot be converted to (such as, an array). Library will raise an error. So do the following:

1. Either make sure which type to convert to. Or
2. Do not convert to a generically passed type, instead use dynamic keyword to deserialize the object and then check its type later on runtime. That still doesn’t guarantee it to work.

My recommendations

Finally, I want to give you a few of my own personal experience tips. In my experience I started to work with data on a database system; SQL Server CE I remember. But later I had to create applications which required a bit complex structures and were not going to last another weak. So in such conditions, using a database table was not a good idea. Instead, I had to use a sample and temporary data source. During those days, XML was a popular framework as per my peers. JSON was something that most didn’t understand. So, in my own humble opinion, you should go with JSON, where:

1. Data needs to be shared cross-platform, cross-browser and cross-server. Databases may be helpful, but even they need serialization and stuff like that.
2. You just need to test the stuff. You can target your Model to the JSON parsers and then in release mode change them to the actual data sources.

That is not it, the size of JSON is “amazingly” compact as compared to XML. For example, have a look here:

// JSON
{
 "name": "Afzaal Ahmad Zeeshan",
 "age": 20,
 "emptyObj": { }
}

// XML
<?xml version="1.0" encoding="UTF-8" ?>
<name>Afzaal Ahmad Zeeshan</name>
<age>20</age>
<emptyObj />

Even in the cases where JSON has nothing in it, XML is bound to have that declaration line. Then other problems come around, such as sending an array, or sending out a native type object. In JSON you can do this,

true

In XML, you don’t have any “true” type. So, you are bound to send something extra. Which can cause to be a bottleneck in the networking transmission. I have been writing many articles, blogs and guides and most of them are based on JSON if not on SQL Server.

Hashing passwords in .NET Core with tips

Previously I had written a few stuff for .NET framework and how to implement basic security concepts on your applications that are working in .NET environment. In this post I want to walk you to implement the same security concepts in your applications that are based on the .NET Core framework. As always there will be 2 topics that I will be covering in this post of mine, I did so before but since that was for .NET itself, I don’t think that works with .NET Core. Besides, .NET Core is different in this matter as compared to .NET framework, one of the major reasons being that there is no “SHA256Managed” (or any other _Managed types in the framework). So the framework is different in this manner. This post would cover the basic concepts and would help you to understand and get started using the methodologies for security.

Figure 1: Data security in your applications is the first step for gaining confidence in clients.

First of all, I would be covering the parts of hashing and I will give you a few of my tips and considerations for hashing the passwords using .NET Core in your applications. Before I start writing the article post, I remember when I was working in Mono Project and the platform was very easy to write for. I was using Xamarin Studio as IDE and the Mono was the runtime being used at that time, in my previous guide although the focus was on the Mono programming on Ubuntu whereas in this post I will covering the concepts of same but with .NET Core. .NET Core is really beautiful, although it is not complete, yet it is very powerful. I am using the following tools at the moment so in case that you want to set up your own programming environment to match mine, you can use them.

1. IDE: Visual Studio Code.
2. C# extension: For C# support and debugging
3. Terminal: Ubuntu provides a native terminal that I am using to execute the command to run the project after I have done working with my source code.

Figure 2: Visual Studio being used for C# programming using .NET Core.

You can download and install these packages on your own system. If you are using Windows, I am unaware as to what Visual Studio Code has to offer, because since the start of Visual Studio Code I have just used it on Ubuntu and on Windows systems my preference is always Visual Studio itself. Also, I am going to use the same project that I had created and I am going to start from there, A Quick Startup Using .NET Core On Linux.

So, let’s get started… 🙂

Hashing passwords

Even before starting to write it, I am considering the thunderstorm of comments that would hit me if I make a small and simple mistake in the points here, such as:

1. Bad practices of hashing.
2. Not using the salts.
3. Bad functions to be used.
4. Etc.

However, I will break the process down since it is just a small program that does the job and there is no very less exaggeration here. Instead of talking about that, I will walk you through many concepts of hashing and how hackers may try to get the passwords where hashing helps you out.

Until now I have written like 3 to 4 articles about hashing, and I can’t find any difference in any of these codes that I have been writing. The common difference is that there are no extra managed code stuff around. .NET Core removed everything redundant in the code samples. So we are left with the simple ones now that we would be using.

What I did was that I just created a simple minimal block of the SHA256 algorithm that would hash the string text that I am going to pass. I used the following code,

// SHA256 is disposable by inheritance.
using (var sha256 = SHA256.Create()) {
    // Send a sample text to hash.
    var hashedBytes = sha256.ComputeHash(Encoding.UTF8.GetBytes("hello world"));
 
    // Get the hashed string.
    var hash = BitConverter.ToString(hashedBytes).Replace("-", "").ToLower();
 
    // Print the string. 
    Console.WriteLine(hash);
}

This code is a bit different from the one being used in .NET framework. In the case of .NET framework the code starts as:

using (var sha256 = new SHA256Managed()) {
     // Crypto code here...
}

That is the only difference here, rest of the stuff is almost alike. The conversion of bytes into string text is upto you. You can either convert the bytes to hexadecimal strings or you can use the BitConverter helper to convert that to the text that is being represented.

The result of this code is,

Figure 3: Result of the above shown code in C# being executed in Ubuntu terminal on .NET Core runtime. 

There is one another constraint here, “Encoding.UTF8“, if you use another encoding for characters then the chances are your hashed string would be different. You can try out other flavors of the character encodings such as:

1. ASCII
2. UTF-8
3. Unicode (.NET framework takes Unicode encoding as UTF-16 LE)
4. Rest of the encodings of Unicode etc.

The reason is that they provide a different byte ordering and this hashing function works on the bytes of the data that are passed.

Tips and considerations

There are generally two namespaces rising, one of them is the very old familiar .NET’s namespace, System.Security.Cryptography, whereas another one is Microsoft.AspNet.Cryptography which is a part of ASP.NET Core and are to be released. Anyways, here are a few of the tips that you should consider before handing the passwords.

Passwords are fragile — handle with care

I can’t think of any online service, offline privacy application, API hosts where passwords are not handled with care. If there is, I would still act as I never knew of it. Passwords must always be hashed before saving in the database. Hashing is done because hashing algorithms are created with one thing in mind, that they are hard (if not impossible) to convert back to plain-text passwords. This makes it harder for the hackers to get the passwords back in the real form. To explain this fact, I converted the code into a functional one and printed the hash with a little change in the text.

private static string getHash(string text) {
    // SHA512 is disposable by inheritance.
    using (var sha256 = SHA256.Create()) {
        // Send a sample text to hash.
        var hashedBytes = sha256.ComputeHash(Encoding.UTF8.GetBytes(text));
   
        // Get the hashed string.
        return BitConverter.ToString(hashedBytes).Replace("-", "").ToLower();
    }
}

I will execute this function and get the hashed string back for the text that have very less difference in them.

string[] passwords = { "PASSWORD", "P@SSW0RD", "password", "p@ssw0rd" };
 
foreach (var password in passwords) {
    Console.WriteLine($"'{password}': '{getHash(password)}'");
}

Although they seem to look alike but have a look at the avalanche effect that happens due to such small changes. Even have a look at the differences in the capital case and small case.

Figure 4: Password hashes being shown in the terminal. 

This helps in many ways, because it is harder to guess what the possible plain-text alternate would be for this hashed string. Remember the constraints again,

1. The character encoding is UTF-8; others would provide a different character encoding bytes ordering.
2. Hash algorithm being used in SHA256, others would produce even different results.

If you don’t hash out the passwords, hackers may try to use most common attacks on your database system to gain privileges of access. A few common type of attacks are:

1. Brute force attack
2. Dictionary attack
3. Rainbow table attack

Rainbow table attack work in a different manner, it tries to convert the hash back to the plain-text based on the database where a password/hash combination is present. Brute force and dictionary attacks use a guessing and commonly used passwords respectively, to gain access. You need to prevent these attacks from happening.

Besides there are cases where your password hashing is useless. Such as when you want to use MD5 hashing algorithms. MD5 algorithms can be easily cracked and the tables for entire password look up are already available and hackers can use those tables to crack your passwords that are hashed using MD5. Even SHA256, SHA512 don’t work as you are going to see in the following section. In such cases you have to add an extra layer of security.

Bonus: how to break it?

Before I continue further, I wanted to share the point of these passwords and their hashes being weaker. There are many hacking tools available, such as reverse look ups. Let us take our first password and see if that can be cracked. I used CrackStation service to crack the password and convert it back to its original text form,

Figure 5: SHA256 based password converted back to its original form. 

See how inefficient even these tricks happen to be. In a later section I will show you how to salt the passwords and what the effect is. Although we had hashed it using SHA256, the reverse lookup table already has that password of ours. Hackers would just try to use that hash and get the real string value in the plain-text to be used for authentication purposes.

Slower algorithms

On networks where hackers are generally going to attack your websites with a script. You should have a hashing algorithm that is (not very) significantly slow. About half a second or 3rd of a second should be enough. The purpose is:

1. It should add a delay to the attacker if they are trying to run a combination of passwords to gain access.
2. It should not affect the UX.

There are many algorithms that keep the iterations to a number of 10,000 or so. The namespace that I had talked of, Microsoft.AspNet.Cryptography has the objects that allow you to specify the iteration, salt addition etc.

Remember: For online applications, do not increase the iteration count. You would indirectly cause a bad UX for the users who are waiting for a response.

Add salt to the recipe

I wonder who started the terminology of salt in cryptography. He must have a good taste in computers, I’d say. I did cover most of the parts of adding the salts in the article that I have added in the references section, please refer to that article. However, I would like to share the code that I have used to generate a random salt for the password. Adding the salt would help you randomize the password itself. Suppose, a user had a password of, “helloserver”, another one had the same password too. By default the hash would be alike but if you add a random salt to it, it would randomize the password.

In .NET Core, you can use the “RandomNumberGenerator” to create the salt that can be used for the password.

private static string getSalt() {
    byte[] bytes = new byte[128 / 8];
    using (var keyGenerator = RandomNumberGenerator.Create()) {
        keyGenerator.GetBytes(bytes);
 
        return BitConverter.ToString(bytes).Replace("-", "").ToLower();
    }
}

This would create a few random bytes and then would return them to be used for the passwords.

string[] passwords = { "PASSWORD", "P@SSW0RD", "password", "p@ssw0rd" };
 
foreach (var password in passwords) {
    string salt = getSalt();
    Console.WriteLine($@"{{
       'password': '{password}', 
       'salt': '{salt}',
       'hash': '{getHash(password + salt)}'
       }}"
    );
}

This shows how the passwords with “random salt” differ.

Figure 6: Passwords with their salts being hashed. 

Have a look at the hashes now. The hashes differ from what they were before. Also, notice that the function returns a different salt every time which makes it possible to generate different hashes for even the similar passwords. One of the benefits of this is, that your passwords would be secure from a rainbow table attack.

Test: We saw that unsalted passwords are easy to be reverse looked up. In this, case, we salted the password and we are going to test the last of our password to see if there is a match.

Figure 7: Password not found.

Great, isn’t it? The password was not matched against any case in the password dictionary. This gives us an extra layer of security because hacker won’t be able to convert the password back to their original form by using a reverse look up table.

Using salt: the good way

There is no good way of using the salt, there is no standard to be followed while adding the salt to the password. It is just an extra “random” string to be added to your password strings before their are hashed. There are many common ways, some add salt to the end, some prepend it some do the both.

Do as you please. 🙂 There are however a few tips that you should keep in mind while salting the passwords.

1. Do not reuse the salts.
2. Do not try to extract the salts from the passwords or usernames.
3. Use suitable salt size; 128-bit?
4. Use random salt.
   • You should consider using a good library for generating the salts.
5. Store the salts and passwords together. Random salts won’t be created again (in a near future).

References:

1. Avalanche effect
2. Hashing Passwords using ASP.NET’s Crypto Class
3. Guide for building C# apps on Ubuntu: Cryptographic helpers
4. What are the differences between dictionary attack and brute force attack?

Final words

In this post, I demonstrated the hashing techniques in .NET Core, although the procedure is similar and very much alike. There are a few differences that the objects are not similar. The object instantiation is not similar and in my own opinion, this is also going to change sooner.

I gave you a good overview of password hashing, how to crack them (actually, how an attacker may crack them) and how you can add an extra layer of security. Besides, you should consider adding more security protocols to your own application to secure it from other hacking techniques too.

Why to use C# and when to prefer other languages?!

Introduction and Background

Either it is Quora, or is it C# Corner or is it CodeProject, beginners and novice users are always asking questions like, “Which one to use, C++ or C#?”, and many more similar questions. It is harder to provide an answer to such questions on multiple platforms and to multiple questions. That is why, I thought, why not post a blog post to cover most of the aspects of the question. In this post I am going to cover a few of the concepts that you may want to understand to chose either language from the most widely used languages:

1. C or C++
2. Java
3. C# (or .NET framework itself)

Basically, my own preference in many cases is C#, but that depends on what I am going to build. I have been using C, C++, Java and C# in many applications depending on their needs, depending on how they allow me to write the programs and depending on whether it is the suitable programming language for this type of project and application architecture.

The way, I do that, is just a trick. Which, I am going to share with you, in this blog post. Among these a few of the very basic things to consider are:

1. How simple and easy it would be to use this language in the program?
2. What is the productivity of that language in your scenario!
3. Difficulty level and how many people know the language!

I will be talking about these things points in this post, so to make it clear where to use which programming language. But my major concern in this post would be to cover the aspects of C# programming language.

Productivity of language

First thing to always consider about the language is the productivity that a programming language can provide your team with. Productivity of the language depends on many factors, such as:

1. How programs are built in that language?
2. How fast and reliable is it to build the project regularly?
3. Is the program’s source code readable for other members on the team?
4. Is the language itself suitable for the case that we are going to use it in.

Productivity of the language, in my opinion, is the first thing to consider as the valid candidate to always discuss in the team and not just talk about in a black room. You should manage to get your teams up in a conference room, and then talk about a language. There may be many aspects where one language may fall short and other may get well. There would be many factors that most of the programmers don’t know but talking about them one of the geek would stand up and raise another important point that may guide your team to walk on the correct paths to build greater applications.

Let’s talk a bit graph.

Figure 1: Productivity graph of most widely used programming languages.

In this chart we can see that C is the most productive programming language, of which we are interested in; C, C++, Java and C#. C++ and C# are competing with each other, whereas Java is a bit behind than C# and so on.

In the above graph, it is clear that C# is an average programming language. The average doesn’t mean it is below the requirement. But it means that it can be used in any case, and its performance won’t fall as the data increases. The successful run graph shows that C# programs are much successful in many cases. That is why, in many cases, C# proves to be the valid candidate in many cases, since it is a general purpose programming language.

Then the question arises, “Productive in which sense?”

That is the most important part here. Now, this topic may take a bit more of the time to explain how productive a language is. For that, I have dedicated the topic, “Choosing the right language for the right task“. The right programming language for the right task would always help you to elevate the speed of the programming of your team! But among other aspects, the most important ones are:

1. What sort of project this is?
   • Of course you don’t want to use knife to unscrew a screw.
2. What are the IDE and compilation tools present?
   • Even a program written in C can go wrong if compile is buggy or inefficient.
3. How your team would like to manage the projects?
   • Does the language support good software engineering concepts?
   • Can it be used to generate good diagrams: Use-case, activity, class and other diagrams.

Thus, you should always consider thinking about the productivity of your development team while guessing which language to be used.

Choosing the right language for the right task

It is always stated to use the best tool for the best jobs! Then, why not use the best programming language for your projects, to get the best possible results? Before I continue any further, there is one thing I want to mentioned… “There is no best programming language ever built.” Every time a programming language is built for a purpose, another group of programmers jump in to create a new programming language, for the sake of fixing the errors in the previous language. What do you think motivated Bjarne to create C++ when there was C language and Scala already in the market?

In this section, there are many things to consider, from the performance and benefits to the clients, to the perk packages for the employees to the efficiencies of the project repositories and the tools provided for that programming languages.

C# was created by Microsoft and therefore, in my opinion, has, by far, the most efficient tools for programming. I mean, Visual Studio, alone is the beast in this game.

Figure 2: Visual Studio logo.

I am a huge fan of Visual Studio, and i would doubt someone who isn’t a fan of Visual Studio. C# has a better support and benefit of using the best IDE out there. Java has also a number of IDE, so does C++ and many of the C programs are written in minimal environments, like a small program to manage and compile the C programs; no offence geeks!

Figure 3: Graph of performance to safety ratio.

Now, if you look at this graph, it’s pretty much clear as to what it is trying to guide you with. Of course, as I had mentioned in the starting paragraph here, that there is no best programming language.

In many cases, C# and Java rule over C++ (and C) and in many cases, they rule over C# and Java. There are many factors, like the programming paradigms, performance of the code that is generated; Just-in-time compilation, memory-management delay and so on. While C# and Java may provide the best environment to build “managed” programs in, there are many cases where C# and java don’t work well, like writing a low-level program. Java developers wanted to build a Java OS, but they had to give up because something’s aren’t meant to be done in Java. 🙂

Always consider to search before making the final call. There are many companies working in the similar field that you are going to work in. There would be many packages and languages built for your own field that may help you to get started in no time!

Figure 4: Top 10 programming languages.

But, I think these are a bit backwards. I think, C is on the top because it causes a lot of trouble to beginners, so everyone is searching for “How to do {this} in C” on Google, raising the rankings. 😉

Selecting the best framework

I don’t totally agree with people when it comes to talk about frameworks like, Java, Qt (which I do like in many cases; like Ubuntu programming), and other programming frameworks available for programming applications to be run despite the architecture of the machine. In this case, my recommendation and personal views for .NET framework are very positive. As, already mentioned, I have programmed on Qt framework for Android, Ubuntu and Linux itself. It was a really very powerful framework to build applications on. But the downside was it was tough to learn, their compilers were modified, their C++ was tinkered.

While selecting the best framework for application development by choices are below:

1. How much flexible a framework is?
2. What language does it support?
   • Some frameworks support multiple languages, like .NET framework, it supports C#, VB.NET, Visual C++, JavaScript applications.
3. Is it cross-platform?
4. If not cross-platform, then does it support multiple architectures, at least?

Java framework is cross-platform, and entirely framework oriented. You simply have to target the framework despite the operating system or architecture being used. .NET framework on the other hand is a very beautiful framework to write applications on. It uses C#, VB.NET and C++ (no Java!) to write the applications, and then the compiled binaries can be executed on many machines that can support .NET framework. This provides an excellent cross-architecture support.

C# however, does not support Mac OS X, at the moment. Microsoft has started to roll out cross-platform binaries for C# programs. .NET Core has been a great success and once it gets released to a public version, I am sure most of the companies would start to target it. That is not going to happen, in a near future. In which case, Java and C++ are better than C#.

If you are interested in C# programming on multiple platforms, consider using Mono Project instead. You can read about that, on my blog here: Using C# for cross-platform development.

Figure 5: Top languages and their platforms of usage.

Java may be supported 100% in the rankings, but C# is also supporting multiple platforms and is rapidly growing making the language better than the rest. With the release of C# 6, Microsoft has proved that the language is much better than the rest in the race. There are many features that I like C# 6:

1. String interpolation
2. Getter-only auto-properties as lambdas
3. Improvements to lambdas

There are a few things Java still doesn’t have. For example, one statement code to write the data to the files and to extract the data. You have to get messy in the streams, or you have to write an entirely non-intuitive code with Files object and then to get the data from there… Yuk!

Performance of the compiled code

Writing the source code may be different in many ways:

1. Syntax of the programming language.
2. The way their objects and procedures are imported in the source code.
3. How clean the source code looks. Many programming languages are just nightmares.

But the major concern comes to mind when we are going to execute the programs. In many cases, or should I say in all the cases, the language which are bytecoded languages, lag behind than the languages that are compiled to native codes or Assembly codes. For example, C or C++ codes are faster, because they are not compiled to a bytecode instead they are generated as machine codes for a platform or architecture. C# or Java programs are compiled down to a bytecode which causes a JIT to occur when the programs are executed. This takes time.

However, you can see the following charts from https://attractivechaos.github.io/plb/ and see for yourself, the way bytecoded languages are similar and how much compiled languages are different, see for yourself.

Figure 6: Mathematical calculations.

Figure 7: Pattern matching and machine learning.

Which makes it pretty much clear, how much compiled language are faster than bytecoded, and then come the ones that are interpreted, like Ruby.

In many cases, there are other factors too, which cause bad performance:

1. Bad compiler.
2. A lot of resources being allocated.
3. Slow hardware resources; bad combination of CPU, RAM and other peripherals.
4. Bad programmer and bad code being used.
5. Bad practices of programming.
6. Keeping CPU halted for most of the times.

Much more are a valid candidates for the halting processes.

Finally… Final words

As I have already mentioned that there is no best programming language out there. One language is best in one case, other is best in another case and so on and so forth. In such cases, it is always better to communicate with your development team and then ask them questions and ask for their feedbacks. Choosing the good tools for your projects is always a good approach and good step in the process of programming.

If your software engineer or software architect are trying to find a good solution, ask them to work on the following questions:

1. What are the teams and developers qualified for?
   • Asking a team of C++ programmers to leave C++ and join Java or C# programming teams is not a good idea!
   • Always consider the best approach.
   • Time is money — Manage it with care.
   • Recruit more programmers with skills.
2. Is the programming language long lived, or a minor one?
3. Is programming language capable of making your application work?
   • I have used many programming languages, and thus I can decide which language to use. This is the job of your software architect to decide which languages to select.

If you follow these rules, you will save yourself from many of the future questions that cause a lot of problems. Many times developers ask questions like, “I have an application in Java, how to migrate it to C#?” Many web developers ask questions like, “I have a PHP application, how to convert PHP code to ASP.NET?” These questions have only answer. “Re-write the applications”.

There are many things that you should consider before designing the applications. Facebook is stuck with PHP, because it was written in PHP. Even if they wanted to migrate to ASP.NET, they won’t. Instead, they have found a work around the PHP bugs and downsides.

This is why, you should always consider using a conference or meeting to decide how to start the project, which programming language to use, what frameworks to target, who would lead the team and much more. These few days of discussion and designing would save you a lot of money and time in future.

Understanding the Visual Studio IDE for R language

Introduction and Background

Previously we had talked much about installing and setting up the environment for R language. In this post, I will walk you through different stuff that Visual Studio provides you with. Typically, every R IDE supports the following tools and features for data processing.

1. A scripting toolkit; where you can write R language code.
2. An R interactive shell for executing the commands.
3. Plot builder for plotting the graphics.
4. Markdown editors and much more.

I will walk you through these windows in Visual Studio IDE itself and would give examples of using Visual Studio as your default IDE for R programming. In my personal (and humble) opinion, I think Visual Studio is the best IDE out there, provided its simplicity, ease of use and now that the price has also dropped down to zero for personal use! What more can someone ask for? 🙂

Exploring Visual Studio for R

I have talked about the things that we are going to explore in this post. Those are listed above, and in this section I am going to expand them and I am going to demonstrate what benefit they have for R developers in the industry of data science.

Figure 1: Visual Studio logo.

Besides R, Visual Studio is also going to have the tools for Java programming. At least, I am very much excited about Visual Studio’s future, in which it is going to be used as a universal IDE. But in this post we should just focus on the R tools provided. If you have not yet set up the R tools for Visual Studio, I recommend that you read the post of mine for that, Installing and setting up R environment on Windows. This would help you to set up the environment for data analysis using R language.

1. R code editor

First thing to know about in any IDE for any programming language, is the code editor that it has. Code editors are simply the text editors, but there are a few other additional features that it has apart from the ordinary text editing and caching services. Visual Studio code editor provides the following powerful features:

1. R syntax highlighting.
   • Every IDE should support syntax highlighting and highlight the different data types, different keywords and the scope resolutions like matching brackets.
2. Autocomplete suggestions.
   • Visual Studio calls them IntelliSense, which provides the easy way of writing the programs. It provides the clean way of providing suggestions for function calls and the parameter lists.
3. Squiggly lines for errors
   • It is better to show off the errors in the language syntax or commands, before programmers build their project and finally stumble upon the errors. Visual Studio shows the errors if there are any, in the commands using the interpreters!

Figure 1: Visual Studio code editor.

This is the most basic usage of the code editor at now.  Visual Studio renders the codes in their own format, R syntax has been implemented in Visual Studio to support for string literals, keywords, comments and matching brackets.

You should consider using the R code editor instead of using a plain-text file to write the R scripts.

2. R interactive shell

Every interpreted programming language has an interactive shell. Python has it, so does R because R is an interpreted language. Interactive shells allow you to execute minimal programs, commands, and test the environment itself. They are also used to compile (interpret!) and execute the statements in the source file that you may have somewhere.

Visual Studio supports the Interactive Shell. If you do not find it, it is right there under R Tools → Windows → R Interactive. The WIndow allows you to enter the commands to:

1. Create new variables in the environment.
2. Explore the environment.
3. Print the variables.
4. Perform calculations on the data.

Figure 2: R interactive shell.

You can see that the R project starts, and then it allows the users to enter the commands that are to be tested or executed in the R environment. If you pay a bit more attention, you will see that i am currently running Microsoft’s R Open,

Figure 3: Microsoft R Open being used in the shell.

This allows you to add the commands which require execution. You can perform many functions in this shell as already mentioned above.

Figure 4: Executing commands in R Interactive Shell.

You can also run other versions of the R. But, Microsoft R Open is the Microsoft’s implementation and distribution of R language. To change the currently active engine to be used for R, you need to have other versions of R installed on your machine. If they are available, then you can update the current active R engine from the settings themselves. Just select R Tools → Options. Inside those options, select the path for the R engine’s installation folder.

Figure 5: Options in R Tools.

Select this field and update the directory which it targets to target another directory for a different R engine. Once done, you can restart the Visual Studio to take the actions.

3. Plotting graphs

Another great feature of R programming is that it provides you with native support for graphical presentations. If you want to build charts, pie charts and bar charts or graphs. You can get the functions that can do the trick for you! In no time, you will be up and running your own projects, presentations and anything.

Benefit is that R generates quality and enterprise ready graphics, not just careless graphics! You can show the R plot window by either executing the command for plotting the graph or by manually opening it. To select the R plot, you can go to R Tools → Windows → R Plot. You can then direct R to build and generate the graphics on the plotter, a few of the commands used are:

1. Pie
2. Plot
3. Barplot

You can use these commands to build the graphics, based on the data sets or vectors that you have. You can consult any of the statistical book or guide to learn more about charts and how they are used to render the data on the graphical level.

Just to demonstrate, I am going to use the following data, assuming they are marks:

> a <- c(55, 73, 44, 85, 65, 76)

Execute this, and R would create a variable in the environment.

Using plot()

First function to use is the plot() function. It plots the dotted graph of the points. Execute the following function,

> plot(a)

Following is the result of this command in the shell:

Figure 6: Plotting the dotted graph.

You can change how text is rendered and how the indices are selected, too!

Using barplot()

Next I would like to talk about the barplot() function that generates the graphics in the bar graph form. You pass the elements, and then it would generate the output in the bars form. The benefit is that you can compare how long a bar is, as compared to another one.

To get a bar graph, execute the following command:

> barplot(a)

The following output would be captured by you:

Figure 7: Bar graph for the data set.

This shows the data in a bar graph form. This is more readable and is easily understood. You can see how our graph is built and how the indices are selected for our data sets. You can then perform other actions, which I will talk about later before ending this section.

Using pie()

Pie is another kind of graphical notation in which we can render the data, to learn about it, read any basic statistical guide or course book. The pie uses the shape of a pie to render the graph. But, it uses the ratio of each data item to slice the pie into different sections to demonstrate their part in the pie.

To build a pie chart, use the following command:

> pie(a)

This would result in the following:

Figure 8: Pie chart graph.

Although this uses 1, 2, 3…6 to label. You can change them later in the function call. But I just want to tell you how Visual Studio can help you to have multiple windows working simultaneously for your project.

Features of R Plot

I mentioned that I will talk about the features of the R Plot. One of the best feature is that they are native. You do not need to import any extra package or library. But you can import other libraries, if you like any other implementation of the graphs.

Secondly, R Plot allows you to import the graphics in the form of:

1. PNG images
2. PDF documents

Which makes it even more easier to share the graphics that you render using the data set of your own environment.

Generating documents — R Markdown

Finally, I would like to talk about the R Markdown a bit. I think, this is one of the best things that R has right now. If you have ever been to Stack Overflow, GitHub or other similar websites, you would know that they already support a markdown that can be used to generate and render the HTML in a much simpler way. For example,

Hello _everyone_! I am using the following code

```
var obj = new Object();
```

// Would result in
<p>Hello <i>everyone</i>! I am using the following code</p>

<pre>
var obj = new Object();
</pre>

Which makes it much easier to render the documents in a much simpler way. Instead of writing a complex, standard or platform based language. You write a third-party standard, which is then converted to another standard. R Markdown does the same thing. You use it to generate the documents. The benefit is that you can use a single R markdown document to build multiple documents of multiple types and kinds:

1. PDF documents
2. HTML documents
3. Word documents
4. Other documents, supported!

Thus, it seriously elevates the document generation for the research that you have just conducted. Plus, it allows embedding the document code which can be executed when needed, such as generating the charts, calculating the means and so on and so forth.

In Visual Studio, you can create a new R Markdown document just the way you would create any other file in Visual Studio. Right click → Add → New Item → R Markdown.

This document can contain the plain-markdown content, which would be then rendered and compiled based on the medium that you want to render the data in.

References

To learn more about R Markdown, please refer to the following links:

1. R Markdown
2. Knitr with R Markdown

Points of Interest

In this post I have talked about and walked you around many aspects of using R programming in Visual Studio IDE. Visual Studio is, no doubt, the best programming IDE available and providing the services for R programming is a great step by Microsoft.

Figure 9: Visual Studio IDE having 4 windows of R tools open.

I assume, using Visual Studio for R programming is pretty much explained in this post, and in the later posts I will walk you through using R language for real projects and real time data processing and analysis.

In the later posts, I will talk about using R programming in real world projects. Hold tight, it’s going to be an excellent data science journey. 🙂

Guide for building C# apps on Ubuntu: Graphical applications using Windows Forms

Introduction and Background

I took more than necessary break in posting the content and articles for Ubuntu programming in C#. Anyways, I am continuing from the same place where I left and, as already taught that we were at the final stages of sharing the guide for programming C# on Ubuntu; which can be thought of as a Linux environment. The previous posts can be found easily on my blog and on some of the networks that I support.

Previously, we had already talked about NuGet gallery packages, cryptographic helpers and much more. Whereas, in this post I am going to walk you people through using Windows Forms framework on Mono framework.

Windows Forms framework

Now, who doesn’t know Windows Forms framework in today’s world? If you have ever wanted to or have developed the C# programs or .NET applications. Then you are already familiar with Windows Forms application. Windows Forms is an old framework with graphical capabilities, and has been in the game for a more than a decade by now! It has started to get replaced by Windows Presentation Foundation, but nonetheless, it is still very popular and is being used widely by many software developers and many software development companies are still relying on it.

There are many benefits of using Windows Forms in your regular development teams,

1. It supports graphics, not just the CPU and RAM processing.
2. It can be used with resources for localization support is excellent.
3. Provides a better way for drawing graphics on canvas.
4. Event handling, delegate generation.
5. Asynchronous programming patterns.
6. Good data binding support provided.

I am going to provide you with some good references that you can use to learn more about Windows Forms, if sadly, you have no idea about the Windows Forms framework. However, one thing is for granted. Using Windows Forms is one of the easiest ways of building the graphical applications in ,NET environment.

References

Follow the following links and learn more about Windows Forms:

1. Windows Forms
2. Getting Started with Windows Forms
3. Windows Forms Overview

Graphical applications in Mono Project

We have until now, discussed and learnt how to build small programs and some very common applications that use special kind of algorithms, such as cryptographic helpers which can be used to encrypt and decrypt the data in Ubuntu using C#. Now, until this we haven’t covered graphical applications development in Mono, because that is where this framework lags behind.  So, in this post we would like to learn how to build applications with graphical capabilities too. But, first, let’s talk about the frameworks provided in Mono Project itself.

1. GTK#
   • Which is a similar one to the GTK+ that C++ programmers have. This is a graphical toolkit that compiles down to the native code generation. It supports the native look and feel and can be used. But, it is somewhat difficult to learn!
     
     Figure 1: GTK# control application example.
2. Windows Forms
   • This is the topic that we are going to cover in this post.
3. Other tools?
   • Not yet, Mono Project is not ready to implement other frameworks yet.

The thing is, Mono Project doesn’t have an excellent UI designer as we have in Visual Studio.

Figure 2: Visual Studio UI Designer.

In Mono Project and Xamarin Studio, you are not provided with the similar tools until now. However, the designer is just the wrapper around the back-end code available. Xamarin Studio does have a good designer, but that works with GTK# tools and controls only. Not in the case of Windows Forms.

Applying a quick hack!

If you have ever programmed for Windows Forms, then you would know that Windows Forms is actually a bunch of objects with many fields and properties, which run and work to render the graphics on the screen. The same is applicable here. We would be using the codes to render the stuff on the screen. Basically, everything that you have on the screen is a field in the backend class, such as “Button”, “TextBox”, “Label” etc. These are all going to be used, but, we are going to write the codes for this, instead of having a designer build them up for us.

Building the UI with Windows Forms

So, I hope using the hack is clear to you, after all, it is not a hack it is the actual way in which Windows Forms applications are constructed, built and executed. Only difference is that on Windows we also get to use the UI designer. In case of Mono Project, we would have to craft the UI with our own codes and then re-implement it if there is a changing to be performed on the screen later. Thus, putting it simply, we are going to implement it the hard way since there is no, “Drag-and-drop” method here.

To get started, you need to understand that a Windows Forms application is a C# application too. So, only thing to understand is C# language itself and the .NET framework. We are going to use the same concepts of .NET framework and then implement the same concepts to Mono to get our graphical applications ready.

Create project — Any type

I had chosen to build this application on the top of Console application. You can select other types too. But, my recommendation is using the Console application.

Figure 3: Selecting the console project as the type.

Enter the names and details and create the project.

Figure 4: Entering the details for the project.

At this moment, you will be at the same stage where you were in the beginning of this module, and the previous ones. You will have an empty project, that only renders, “Hello world”. That is the start, from here we will continue to build the larger and complex stuff.

Figure 5: Hello world!

This program is the default program that every time we were shown. Now, we need to add the graphics to the console. That’s simple. All we need to do is… Read the next section. 😉

Adding graphics to the console

Adding the graphics to the console is pretty much simple, you just need to do the trick as:

1. Include the System.Windows.Forms namespace to the project.
2. Include the System.Drawing namespace to the project.
3. Import the packages to your source code.
4. Write the code yourself; since we do not have the designer.
5. Run the program, and you will see the program start up.

But, I am going to show you how to do that in a minute or two. But first, let us understand why Windows Forms can be build using the code itself. The thing is, the Windows Forms applications are started on a thread, the thread gets the graphics objects and bitmaps which are rendered on the screen later. The objects are simply instances of the classes, for instance of Button class. These are all passed to the Application object, and they are executed, upon execution they render the graphics on the screen.

Another thing to understand and note is that Windows Forms uses System.Drawing to draw the native code in Mono. Mono targets the objects using the assemblies provided in System.Drawing namespace, and then renders the objects on the screen. At the moment, Mono supports on Win32 theme for the objects. In the end of this post, you will see how your objects are going to look. Remember, the objects are instances… 🙂

Open the references and add the references to System.Windows.Forms and System.Drawing namespaces,

Figure 6: Initially references are like this.

Figure 7: Adding the references to the namespaces. 

Now that we have everything set up, we can now continue to create a new Windows Form. This method is not similar to what we had in the previous IDEs, like Visual Studio. Instead, we are going to just mimic having a Windows Form.

Adding the Windows Form to your project

First thing to note is that there is no way of creating the form by itself in Mono Project. So, we are going to create a new object, and then we are going to turn it into the form and then render it using the main function. That’s just similar to what happens in Visual Studio too. You create the form, whose graphics are rendered separately in a designer, and the codefile is generated separately. Visual Studio maintains everything for you, which is why you do not feel anything different.

Step 1:

Create a new class, name it what you like, I chose MyForm and then write the following code to it.

using System;
using System.Windows.Forms;

namespace GraphicalApp
{
    public class MyForm : Form
    {
        // No properties.

        public MyForm ()
        {
            // Default constructor
        }

        // No functions.
    }
}

This is it. This is out, Windows Form now.

Step 2:

Before running the program, you also need to make sure that the main function now calls this form to be executed in the application too.

// In the references
using System.Windows.Forms;

// In the main function
Application.Run(new MyForm());

Now, run the project and you will (should!) see the following window with no controls, but with a graphical notation and rendering.

Figure 8: Sample empty Windows Form application.

This shows that our project is ready to accept the objects for graphical components. We can now write the code for the objects that we need to render. For example and for the sake of simplicity I would like to create a sample form that renders the form, which would ask me about my name and then would greet me once I click on the button.

All of these are core C# programming concepts and this has nothing to do with the Windows Forms or any other fundamental concept. Instead, these are very simple and yet easy features of C# programming language itself.

Step 3:

Anyways, to update, we can just update the MyForm class and write the code that we would need to have in order to render the form.

using System;
using System.Windows.Forms;
using System.Drawing;

namespace GraphicalApp
{
    public class MyForm : Form
    {
        // Properties.
        private Label label;
        private TextBox myName;
        private Button btn;

        public MyForm ()
        {
            // Call the function to render the objects.
            Text = "Windows Forms app";

            this.Size = new Size(300, 350);
            render();
        }

        private void render() {
            label = new Label { Text = "Your name: ", Location = new Point(10, 35) };
            myName = new TextBox { Location = new Point(10, 60), Width = 150 };
            btn = new Button { Text = "Submit", Location = new Point(10, 100) };
            btn.Click += Btn_Click; // Handle the event.

            // Attach these objects to the graphics window.
            this.Controls.Add(label);
            this.Controls.Add(myName);
            this.Controls.Add(btn);
        }

        // Handler
        void Btn_Click (object sender, EventArgs e)
        {
            MessageBox.Show ("Hello, " + myName.Text + "!");
        }
    }
}

Now again run the program, and you will see the following graphical application being rendered on the screen for you!

Figure 9: This is the Windows Forms application on Ubuntu. 

Figure 10: Entering the data and seeing that it works. 

Now, if you have been an old geek for Microsoft and Windows, then you would know that this style existed for decades in Windows environment. This style was typically adopted for Windows programming with C++, especially Win32 and then later C# was introduced and they had a different style; create a WPF app and look for yourself!

This is how Mono does the trick for Windows Forms. It does support Windows Forms and can use the same power of .NET framework to provide the similar ways to build the graphical applications for Linux environment. The benefit is that, you can now execute, build and run these graphical applications on Windows, Linux (every distro that supports Mono runtime) and Mac OS X. What more could you ask for? 🙂

Points of Interest

In this post, i have walked you through different stages of building the graphical applications on Ubuntu using C# in Mono Project. The benefit of using graphical applications is that you can do more in less area, because “A picture worth a thousand words!”. Windows Forms is a framework that has been widely used by programmers of C# language and is still being used. If you can port your applications of Windows Forms to other platforms, it would be much better.

In this post, I have shown you how to do that. You can port your Windows Forms application, by porting the code for that application project, and then building it under Mono compilers.

The Mono runtime however, only supports Win32 theme for controls and however, provides a versatile amount of features, incredibly, they support all the new features of Windows Forms too. Which means, you can work around with:

1. Graphics
2. Multimedia
3. Content management
4. Data binding
5. Event handling
6. Asynchronous programming

And much more. There are more posts about Mono framework to come, but we are getting closer to having the guide completed and to be ready as a complete guide for “Programming C# on Linux”; or Ubuntu, what-ever you prefer. 🙂

What Windows Runtime can teach .NET developers?

Introduction and Background

C# programming language has evolved too much in these years and many frameworks and platforms have been created and developed that support C# language as their primary programming language. Indeed, C# was release with .NET framework but has grown out to support Windows Runtime applications, ASP.NET applications, many .NET framework platforms such as WPF, WinForms etc. I have programmed for all of these frameworks, taught beginners in these frameworks and also wrote a lot of articles for these frameworks. However, the framework that appealed my interests the most was Windows Runtime. Windows Runtime is the new kid on the block with an object-oriented design and performance factor much similar to that of C++ applications.

At a higher-level it seems very simple, easy and straight-forward application development framework. At its core, it has great amount of validations and check points and most of the times, it is pain in somewhere censored. I remember the days when I was developing applications for .NET framework. WPF, WinForms, ASP.NET and other similar ones. I did have a few problems learning and starting, but there was one thing: Underlying framework was a very patient one. They never showed hatred for beginners or newbies. But when I started to write applications for Windows Runtime, I found out that it had no patience in it, at all. It was like, do this or it’s not gonna work.

Figure 1: Windows kernel services and how it branches into different frameworks. 

In this post, I am going to collectively talk about a few things that Windows Runtime may teach C# programmers, for a better overview of the applications that they are going to develop.

1. As a framework

Windows Runtime came into existence way after .NET framework itself and the child frameworks of .NET framework. But one thing that I find in Windows Runtime is that it is very much based on asynchronous patterns for programming. Microsoft never wanted to provide a good UI and UX but to leave out the performance factors.

One of the things that I find in Windows Runtime is that it still uses the same philosophy of C# programming language. But, adds the asynchronous pattern, too much. Not too much in a bad way, but in a positive way. The benefit is that you get to perform many things at the same time and let the framework handle stuff. So a few of the things that it teaches are, that you should always consider having tasks when there is a chance of latency.

1. Network
2. File I/O
3. Long running tasks

These are the bottlenecks in the performance. Windows Runtime allows you to overcome these. .NET framework also uses the same mechanism, but developers typically leave out that part and go for the non-async functions. Bad practice!

References

For more on asynchronous programming, please refer to:

1. Diving deep with WinRT and await
2. Asynchronous Programming with Async and Await

2. Modularity

C++ programmers have been using modular programming, developing small snippets of codes and then using them here and there. Basically, modularity provides you with an efficient way of reusing the code in many areas of the application. Windows Runtime has a great modularity philosophy.

The foundation has been laid down on categories, and under those categories there are namespaces that contain the objects that communicate and bring an outstanding experience for the developers.

C# is an object-oriented programming, which means that even if you’re forcing yourself to have a single source file. You are still going to have multiple objects, working collectively for each of the purpose of that application.

Yet, it is recommended that you keep things where they belong.

Figure 2: Modules can contain the functionality in them, through which user can communicate with the underlying objects and data sources.

References

1. Windows API reference for Windows Runtime apps
2. Modularity

3. Simplicity of the development

I don’t want to lie here, Windows Runtime is simple, it takes times to understand its simplicity. 😉

When I started to write applications for Windows Runtime framework, I did not understand the framework or how to develop the application. That is because, I was fond of straight-forward small programs. Windows Runtime is a beast, a humungousaur, with its handles hanging down to the developers through the interfaces of C# language.

Windows Runtime has everything already set up in different areas. Like, the views, source code, capabilities, properties, resources and much more.

Visual Studio brings a way more simpler mean of development. I mean, Visual Studio handled everything,

1. Managing the source code.
2. Managing the output directories and how binaries are generated.
3. Managing the visual items; the image assets may be difficult to add, Visual Studio makes it really very easy to add the assets of different sizes.
4. The properties and manifest of the application is also written in XML. But Visual Studio makes really very simple to edit and update the manifest of the application.

While building applications for other platforms and frameworks, like WPF, we can use the same philosophy of Windows Runtime to build a great project and package directory. The settings and configuration files can be kep separate to make it simpler to build the development process.

4. Keep all architectures in mind

.NET framework developers don’t have to worry about the architecture that they are going to target. That made them forget the way that application would be targeted on multiple devices and environments. Windows Runtime is not like that. Windows Runtime generates multiple binaries for multiple environments, multiple architectures and devices.

1. x86
2. x64
3. ARM

These are a few of the configurations for which binaries are generated and since the code that gets generated in a native one. The code must match the architecture, otherwise, the results are undefined.

However implementing the multiple architecture pattern would also require more manpower, more time for testing and implementing the patterns. Windows Runtime in Visual Studio has all of that already supported, but thing is, you need your men ready for any new framework to be included and tested on.

5. You may want to test it again!

Before, Windows Runtime, I thought, if everything works correctly. It is going to work anyways. But, ever since I had started to write applications for Windows Runtime and Windows Store I forgot that mind set and wanted to ensure that it passed all of the tests that it must undergo. That all started when I was about to upload my application, “Note It! App” to Windows Store. Application was passing all of the tests in Debug mode. Yet, when it was tested in the Release mode, it failed many of the tests.

Note: I am not talking about the Windows App Certification Tests.

The thing is, the code in the Debug mode has a debugger attached, which knows when something is going wrong and tells the developers about it and we can fix it. In Release mode, it is not the same. The error checks, the memory segmentation and other stuff in Windows Runtime is not same as it is in .NET framework. .NET framework uses Just-in-time compilation and performs many checks. However, in Windows Runtime, that is not the case. Everything is pre-compiled to overcome the JIT latency; delay.

That is exactly why, you should build the application in debug mode. However, always test the applications in Release mode. If you test the application in debug mode, you will skip a few of the key points in your application where it needs to be checked against.

Also, at the end, the App Cert Kit would be found useful to test if other tests, like resources, binaries and signature packaging is all well.

Figure 3: App Certification Kit.

References

For more about it, read these:

1. Release IS NOT Debug: 64bit Optimizations and C# Method Inlining in Release Build Call Stacks
2. Debugging Release Mode Problems

Points of Interest

No developer wants to publish their buggy and faulty application on the Internet. I try, not to publish the application until it has passed every possible condition of test. However, no software is 100% bug-free and perfect solution.

In this post, I didn’t mean to target Windows Runtime as an ideal case for solution building, instead I wanted to just share a few of the great cards it has up its sleeves. .NET framework is simple, easy and agile to build on. But agility may drive you insane someday sooner.

Always keep these things on mind, and write applications by keeping these things in mind.