C# HTTP Server

This is a basic HTTP server implementation from scratch made for the CodeCrafters "Build Your Own HTTP Server" challenge.

What I Learned

Built-In C# Libraries

• System.Net and System.Net.Sockets: Used for creating TCP listeners and handling network streams.
• System.Threading: Used threading and tasks to support multiple, concurrent requests.
• System.Text: Used for encoding and decoding text data.
• System.IO: Used for file operations.
• System.IO.Compression: Used for compressing data streams.

HTTP Concepts

• HTTP Methods: Implemented basic handling for GET and POST requests.
• Headers: Learned how to parse and use HTTP headers.
• Status Codes: Learned some new HTTP status codes like 405 Method Not Allowed.
• Content Encoding: Implemented support for gzip content encoding.

C# Features

• Asynchronous Programming: Used async and await for asynchronous IO operations.
• LINQ: Used LINQ for string manipulation and collection operations.
• File Handling: Learned how to read from and write to files.

How to Run

Ensure you have .NET 8.0 installed

Follow these steps to run the project:

1. Clone the repository:

   git clone https://github.com/OmarAshraf-02/HttpServer.git

2. Navigate to the project directory:

   cd HttpServer

3. Build the project:

   dotnet build

4. Run the server:

   dotnet run

The server will start and listen on the specified port. You can send HTTP requests to test its functionality.

Supported Requests

GET Requests

GET /

To make a GET request, you can use curl:

curl -v http://localhost:4221/

This will return a 200 Success response.

GET /unsupported

curl -v http://localhost:4221/abcdefg

This will return a 404 Not Found response as it is not defined in the server.

GET /echo/{str}

curl -v http://localhost:4221/echo/foo

This will return a 200 Success response, along with the Content-Type: text/plain & Content-Length with the length of your {str} in the path. It will also append the {str} to the response body.

GET /echo/{str} with Accept-Encoding header

curl -v --header "Accept-Encoding: gzip" http://localhost:4221/echo/foo

This will return a 200 Success response. The raw {str} will be gzip encoded by the server and then appended to the response body.

If you're using curl and want to see the response body in the terminal, use the --output - curl option (however this will be gibberish and may mess up your terminal).

Content-Length will be set to the length of the gzip encoded data and the Content-Type: text/plain.

If Accept-Encoding is set to a comma-separated list of encoding methods, this will be parsed by the server to see if gzip is one of the options, so a request such as this will also work:

curl -v --header "Accept-Encoding: encoding1, gzip, encoding2" http://localhost:4221/echo/foo

GET /user-agent

curl -v --header "User-Agent: foobar/1.2.3" http://localhost:4221/user-agent

For this request, the server parses the User-Agent header and responds with a 200 Success with Content-Type: text/plain & Content-Length set to the length of your User-Agent header's value. This value will also be appended to the response body.

GET /files/{filename}

curl -i http://localhost:4221/files/foo.txt

This request will search for a file with the name filename in the /data directory in the project root (not src).

If a file with the same name is found, a 200 Success response will be returned with Content-Type: application/octet-stream & Content-Length set to the size of the file in bytes. The file contents will also be appended to the response body.

If the file is not found, a 404 Not Found response is returned.

foo.txt is included in the /data folder of the repository as an example for testing.

POST Requests

POST /unsupported

curl -v --data "12345" -H "Content-Type: application/octet-stream" http://localhost:4221/unsupported

Any unsupported post request will return a 404 Not Found response.

POST /files/{filename}

curl -v --data "12345" -H "Content-Type: application/octet-stream" http://localhost:4221/files/foo

If a POST request is sent to /files/{filename}, a file with the name filename will be created in the project's /data directory. This file's contents will consist of the contents of the request body (In the above case = 12345). A 201 Created response will then be returned by the server.