URL Encoding in C#

Bilal Shahid Oct 12, 2023

Csharp Csharp Encoding

Use Simple ASCII to Encode Characters in C#
Different URL Encoding Options in C#
Other Encoding Functions Present in System.Web in C#
Use Uri.HexEscape() to Modify Single Characters in a String in C#
Use Temboo to Encode URL in C#
Conclusion

This article will discuss how to encode a URL in C#.

Use Simple `ASCII` to Encode Characters in `C#`

It represents the DECIMAL value of each character on the keyboard. Hence, this DECIMAL value can be substituted for one of the characters in a string and then encoded efficiently.

using System;

class Program {
  static void Main(string[] args) {
    string s = "DelftStack";
    string ascii_convert = "";
    foreach (char c in s) {
      ascii_convert += System.Convert.ToInt32(c);
    }
    Console.WriteLine("The converted ascii string is: " + ascii_convert);
  }
}

Notice that the System.Convert.ToInt32() tends to present the DECIMAL representation of a character in a string. Once the character is converted, its value is then appended to the new string ASCII_CONVERT, which now represents the encoded string.

Rather than using DECIMAL, you can even choose BINARY, OCTAL, or HEXADECIMAL conversions for your encoding needs.

Different URL Encoding Options in `C#`

In C#, we have a variety of encoding functions to use. Many convert characters to different notations, such as URL, URI, HEX etc.

Let’s go forward and write a function to convert a simple URL to these various notations.

First, add the System.Web namespace to our code file. Then call the function to encode the string into URL format that will convert the /, ., " in the string to its ASCII (hexadecimal) representation.

using System;
using System.Web;

class Program {
  static void Main(string[] args) {
    Console.WriteLine(HttpUtility.UrlEncode("https://www.google.com"));
  }
}

Output:

https%3a%2f%2fwww.google.com

Many times such a representation will cause issues in recognition by other systems. It is recommended to make sure to encode only not-so-important information.

In the above example, we would always want google to be accessible. However, a representation in another format may render it void and unrecognizable.

Hence it is necessary to call encoding on terms that belong to the URL but are user-specific. Let’s say now that I search "World" on Google.

The URL would become:

https://www.google.com/search?q=World

The q here stands for Query. Use the following code to encode it.

Example Code:

using System;
using System.Web;

class Program {
  static void Main(string[] args) {
    Console.WriteLine("https://www.google.com/search" + HttpUtility.UrlEncode("?q=World"));
  }
}

Output:

https://www.google.com/search%3fq%3dWorld

Other Encoding Functions Present in `System.Web` in `C#`

Example Code:

using System;
using System.Web;

class Program {
  static void Main(string[] args) {
    Console.WriteLine("URL ENCODE UNICODE: " +
                      HttpUtility.UrlEncodeUnicode("https://www.google.com/search?q=World"));
    Console.WriteLine("URL PATH ENCODE: " +
                      HttpUtility.UrlPathEncode("https://www.google.com/search?q=World"));
    Console.WriteLine("URI ESCAPE DATASTRING: " +
                      Uri.EscapeDataString("https://www.google.com/search?q=World"));
    Console.WriteLine("URL ESCAPE URI STRING: " +
                      Uri.EscapeUriString("https://www.google.com/search?q=World"));
    Console.WriteLine("HTML ENCODE: " +
                      HttpUtility.HtmlEncode("https://www.google.com/search?q=World"));
    Console.WriteLine("HTML ATTRIBUTE ENCODE: " +
                      HttpUtility.HtmlAttributeEncode("https://www.google.com/search?q=World"));
  }
}

Output:

URL ENCODE UNICODE: https%3a%2f%2fwww.google.com%2fsearch%3fq%3dWorld
URL PATH ENCODE: https://www.google.com/search?q=World
URI ESCAPE DATASTRING: https%3A%2F%2Fwww.google.com%2Fsearch%3Fq%3DWorld
URL ESCAPE URI STRING: https://www.google.com/search?q=World
HTML ENCODE: https://www.google.com/search?q=World
HTML ATTRIBUTE ENCODE: https://www.google.com/search?q=World

Notice that the HttpUtility.UrlPathEncode(), Uri.EscapeUriString(), HttpUtility.HtmlEncode() and HttpUtility.HtmlAttributeEncode() tend to present the same results as the unencoded string.

Use `Uri.HexEscape()` to Modify Single Characters in a String in `C#`

Let’s create a function to randomly modify characters in a URL string in C# and then return the encoded string.

static string encoded_url(string param) {
  Random rd = new Random();
  int rand_num = rd.Next(0, param.Length - 1);
  param = param.Remove(rand_num, 1);
  param = param.Insert(rand_num, Uri.HexEscape(param[rand_num]));

  return param;
}

Call the in the main as follows.

Console.WriteLine("URI HEX ESCAPE for 'GOOGLE', called at 1: " +
                  encoded_url("https://www.google.com/search?q=World"));
Console.WriteLine("URI HEX ESCAPE for 'GOOGLE', called at 2: " +
                  encoded_url("https://www.google.com/search?q=World"));
Console.WriteLine("URI HEX ESCAPE for 'GOOGLE', called at 3: " +
                  encoded_url("https://www.google.com/search?q=World"));

Complete Source Code:

using System;
using System.Web;

class Program {
  static string encoded_url(string param) {
    Random rd = new Random();
    int rand_num = rd.Next(0, param.Length - 1);
    param = param.Remove(rand_num, 1);  /// returning the
    param = param.Insert(rand_num, Uri.HexEscape(param[rand_num]));

    return param;
  }

  static void Main(string[] args) {
    // string s = Console.ReadLine();
    // string ascii_convert = "";
    // foreach (char c in s)
    //{
    //     ascii_convert += System.Convert.ToInt32(c);
    // }
    // Console.WriteLine("The converted ascii string is: " + ascii_convert);
    // Console.ReadKey();

    Console.WriteLine("URI HEX ESCAPE for 'GOOGLE', called at 1: " +
                      encoded_url("https://www.google.com/search?q=World"));
    Console.WriteLine("URI HEX ESCAPE for 'GOOGLE', called at 2: " +
                      encoded_url("https://www.google.com/search?q=World"));
    Console.WriteLine("URI HEX ESCAPE for 'GOOGLE', called at 3: " +
                      encoded_url("https://www.google.com/search?q=World"));
  }
}

Output:

URI HEX ESCAPE for 'GOOGLE', called at 1: https://www.%6Foogle.com/search?q=World
URI HEX ESCAPE for 'GOOGLE', called at 2: https://www.go%67gle.com/search?q=World
URI HEX ESCAPE for 'GOOGLE', called at 3: https://www.google%63com/search?q=World

See how characters are converted to their HEX representations at random positions. You can also use this URI.HexEscape() function in a loop to modify the whole string or the desired characters.

URLENCODE stays best for browser compatibility and use. Also, to clarify the use of URI and HTTPUTILITY, remember that URI is inherited from the SYSTEM class, already present within the client C# code.

If you are not using SYSTEM.WEB, you are better off using URI and then calling the encoding functions.

However, using SYSTEM.WEB as a namespace shouldn’t be trouble in many instances. In case your project is compiled in .NET FRAMEWORK CLIENT PROFILE, it isn’t much you can do except copy the code files into a new project.

The .NET FRAMEWORK CLIENT PROFILE will not be able to use SYSTEM.WEB. Simple .NET FRAMEWORK 4 must be utilized when naming SYSTEM.WEB.

Use Temboo to Encode URL in `C#`

An API called TEMBOO tends to encode a URL perfectly.

Example Code:

// the NAMESPACES TO USE BEFORE UTILIZING THEIR CODE
using Temboo.Core;
using Temboo.Library.Utilities.Encoding;

TembooSession session = new TembooSession("ACCOUNT_NAME", "APP_NAME", "APP_KEY");

URLEncode urlEncodeChoreo = new URLEncode(session);

urlEncodeChoreo.setText("https://www.google.com/search?q=");

URLEncodeResultSet urlEncodeResults = urlEncodeChoreo.execute();

Console.WriteLine(urlEncodeResults.URLEncodedText);

Conclusion

While encoding, make sure there are illegal characters that will be converted. If you don’t, switch to the first solution and create a mixed-function that will use SWITCH cases to determine which parts to encode and which not to encode.

In the end, encoding is up to the user. A function that might switch illegal characters and ASCII’s would need a similar decoder on the opposite end.

Hence, using it in a system with a global encoder/decoder for URL/Strings is best.

Author: Bilal Shahid

Hello, I am Bilal, a research enthusiast who tends to break and make code from scratch. I dwell deep into the latest issues faced by the developer community and provide answers and different solutions. Apart from that, I am just another normal developer with a laptop, a mug of coffee, some biscuits and a thick spectacle!

GitHub

Use Simple ASCII to Encode Characters in C#

Different URL Encoding Options in C#

Other Encoding Functions Present in System.Web in C#

Use Uri.HexEscape() to Modify Single Characters in a String in C#

Use Temboo to Encode URL in C#

Conclusion

Use Simple `ASCII` to Encode Characters in `C#`

Different URL Encoding Options in `C#`

Other Encoding Functions Present in `System.Web` in `C#`

Use `Uri.HexEscape()` to Modify Single Characters in a String in `C#`

Use Temboo to Encode URL in `C#`