HTTP Server in C++

A low-level HTTP server built from scratch in modern C++ using Linux sockets.

This project is focused on understanding how the web actually works internally instead of relying on existing frameworks or libraries.

The goal is to gradually build a real HTTP server while learning:

• TCP/IP networking
• Linux sockets
• HTTP protocol internals
• Request parsing
• Concurrency
• Server architecture
• Systems programming in C++

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Current Features

TCP Socket Server

• Creates a TCP socket using Linux socket APIs
• Binds the socket to a port
• Listens for incoming client connections
• Accepts client connections manually

Concepts explored:

• socket()
• bind()
• listen()
• accept()
• recv()
• send()
• File descriptors
• TCP streams

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Basic HTTP Handling

The server can:

• Receive raw HTTP requests
• Parse incoming request data
• Detect HTTP methods and paths
• Send properly formatted HTTP responses

Example request:

GET / HTTP/1.1
Host: localhost:8080

Example response:

HTTP/1.1 200 OK
Content-Type: text/plain
Content-Length: 13

Hello, World!

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Manual HTTP Parsing

This project intentionally avoids external HTTP libraries.

Requests are parsed manually to understand:

• HTTP request structure
• Headers
• Methods
• Paths
• Body handling
• CRLF separation
• Content-Length

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Linux-Focused Development

The server is being developed primarily on Linux.

This project explores:

• POSIX socket APIs
• Terminal networking tools
• Linux networking behavior
• System-level programming

Useful tools used during development:

curl
netcat (nc)
ss
netstat
strace

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Project Goals

This is not intended to remain a simple "Hello World" socket server.

The long-term goal is to progressively evolve it into a more complete HTTP server framework.

Planned areas of exploration:

• Proper HTTP parser
• Incremental parsing
• Keep-alive connections
• Thread pool
• Routing system
• Middleware
• Static file serving
• MIME types
• Logging system
• Non-blocking sockets
• epoll
• Benchmarking
• Security protections
• HTTP compliance improvements

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Why Build an HTTP Server?

Building an HTTP server teaches concepts that are usually hidden behind frameworks.

This project helps understand:

• How browsers communicate with servers
• How APIs work internally
• How TCP differs from HTTP
• Why parsing network protocols is difficult
• How operating systems manage network communication
• How backend frameworks are designed internally

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Example Test Requests

Using curl:

curl http://localhost:8080

POST request:

curl -X POST \
     -H "Content-Type: application/json" \
     -d '{"message":"hello"}' \
     http://localhost:8080

Using netcat:

nc localhost 8080

Then manually type:

GET / HTTP/1.1
Host: localhost

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Build

Example:

g++ -std=c++17 src/main.cpp -o server

Run:

./server

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Project Structure

Current structure is intentionally simple and will evolve over time.

.
├── src/
├── include/
├── public/
└── README.md

Planned future structure:

src/
├── tcp/
├── http/
├── parser/
├── routing/
├── utils/
└── server/

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Learning Focus

This project prioritizes:

• Understanding over abstraction
• Simplicity over premature optimization
• Systems knowledge over framework usage
• Building components manually

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References

Useful resources while learning:

• RFC 9110 (HTTP Semantics)
• Beej's Guide to Network Programming
• Linux man pages
• TCP/IP Illustrated

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Status

Work in progress.

The server is currently in the foundational stage where the focus is on:

• reliable socket communication
• understanding HTTP structure
• building parsing logic
• designing clean architecture

More features and refactoring will be added progressively.

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License

MIT License

Author

Kairav Dutta