HTTP Server Lab

This project is a HTTP server implemented in Go. It is designed as a learning exercise to help understand how HTTP servers work at a low level, including handling TCP connections, parsing HTTP requests, and generating HTTP responses.

Features

• Listens for HTTP requests on TCP port 4221
• Handles multiple endpoints:
  • / — Default response
  • /echo/<text> — Echoes back the text, supports gzip encoding if requested
  • /user-agent — Returns the User-Agent header sent by the client
  • /files/<filename> —
    • GET: Returns the contents of a file from /tmp/
    • POST: Writes the request body to a file in /tmp/
• Properly handles HTTP headers, including Connection: close and Accept-Encoding: gzip
• Returns appropriate HTTP status codes (200, 201, 404, 500)

Project Structure

go.mod
README.md
app/
  main.go                # Entry point, starts the server and handles connections
  controller/
    defaultController.go # Handles requests to `/`
    echoController.go    # Handles `/echo/<text>` endpoint
    filesController.go   # Handles `/files/<filename>` endpoint
    userAgentController.go # Handles `/user-agent` endpoint
  utils/
    utils.go              # Utilities for reading/writing files and compressing content
  request/
    request.go           # HTTP request parsing utilities
  response/
    response.go          # HTTP response formatting utilities

How It Works

• The server listens for TCP connections.
• For each connection, it reads and parses the HTTP request.
• Based on the request path and method, it dispatches to the appropriate controller.
• Controllers build and send HTTP responses, including headers and body.
• Supports gzip compression for echo responses if requested by the client.

Running the Server

1. Make sure you have Go installed (version 1.24.1 or later).

2. Run the server:

   go run app/main.go -port=8000

3. The server will listen on 0.0.0.0:4221 by default.

Running on docker

docker buildx bake
docker run -d --name http-server -p 8000:8000 rafaeldev0ps/laboratory:http-server

Example Requests

• Echo:

  curl -v http://localhost:4221/echo/hello
  curl -v -H "Accept-Encoding: gzip" http://localhost:4221/echo/abc
  

• User-Agent:

  curl -v http://localhost:4221/user-agent -H "User-Agent: strawberry/strawberry"
  

• File GET:

  curl -i -v http://localhost:4221/files/test.json
  

• File POST:

  curl -v -X POST --data '{"animal": "gorilla"}' -H "Content-Type: application/json" http://localhost:4221/files/test.json
  curl -v --data "12345" -H "Content-Type: application/octet-stream" http://localhost:4221/files/file_123
  

Learning Goals

• Understand how to work with raw TCP connections in Go
• Learn how HTTP requests and responses are structured
• Practice parsing and generating HTTP headers and bodies
• Implement basic file I/O and content encoding

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Feel free to explore the code and experiment with adding new features or endpoints!