HTTP from TCP - A TCP-based HTTP/1.1 Server Implementation in Go

My semi-guided attempt at building an HTTP/1.1 server implementation in Go, built directly on top of TCP. This project demonstrates how to handle HTTP requests at the TCP level, implementing some of the HTTP/1.1 protocol specifications. It also includes a TCP listener and UDP sender for debugging and testing purposes.

Features

• Pure TCP-based HTTP/1.1 server implementation
• Support for common HTTP methods (GET, POST)
• Chunked transfer encoding support
• HTTP header parsing and manipulation
• Request body handling with Content-Length validation
• Multiple connection handling with goroutines
• Custom response writer with status codes, headers, and body support
• Example handlers for different HTTP scenarios

Getting Started

Prerequisites

• Go 1.24.2 or higher

Installation

git clone https://github.com/isotronic/httpfromtcp.git
cd httpfromtcp
go mod download

Running the Servers

The project includes several example servers:

1. HTTP Server (main implementation):

go run cmd/httpserver/main.go

This starts an HTTP server on port 42069 with the following endpoints:

• / - Returns a 200 OK response with HTML content
• /video - Serves a video file (requires assets/vim.mp4)
• /yourproblem - Returns a 400 Bad Request response
• /myproblem - Returns a 500 Internal Server Error response
• /httpbin/* - Proxies requests to httpbin.org with chunked transfer encoding

2. TCP Listener (for debugging):

go run cmd/tcplistener/main.go

This starts a basic TCP server that prints received HTTP requests.

3. UDP Sender (for testing):

go run cmd/udpsender/main.go

A simple UDP client for testing purposes.

Project Structure

.
├── cmd/
│   ├── httpserver/    # Main HTTP server implementation
│   ├── tcplistener/   # TCP debugging server
│   └── udpsender/     # UDP test client
├── internal/
│   ├── headers/       # HTTP headers implementation
│   ├── request/       # HTTP request parsing
│   ├── response/      # HTTP response writing
│   └── server/        # Server core functionality
└── assets/           # Static assets (not included in repo)

Testing

Run the test suite:

go test ./...

The project includes comprehensive tests for request parsing, header handling, and server functionality.

Implementation Details

• Built directly on top of TCP connections using Go's net package
• Implements HTTP/1.1 protocol features including:
  • Request line parsing
  • Header parsing and validation
  • Body handling with Content-Length
  • Chunked transfer encoding
  • Trailer headers
• Uses a state machine approach for parsing HTTP requests
• Supports concurrent connections using goroutines

License

This project is licensed under the MIT License - see the LICENSE file for details.