Titan: C++ HTTP Server (Linux)

A small, from-scratch HTTP/1.1 server built in C++ with Linux system calls. The goal is to learn the low-level pieces behind common servers like nginx: sockets, epoll, threads, and basic HTTP parsing. It is not production-ready, but it is a clear and honest implementation you can read end-to-end.

What this project covers

• Event-driven I/O with edge-triggered epoll
• A simple thread pool for blocking work (CGI, disk I/O)
• Zero-copy static file responses with sendfile
• Minimal HTTP/1.1 request parsing (GET, POST, DELETE)
• CGI execution with fork, execve, pipe, and dup2
• A live dashboard that polls /stats

How it works (high level)

• The main thread accepts connections and watches them with epoll.
• When a socket is ready, the request is parsed and routed.
• Blocking work is dispatched to a worker thread.
• Static files are served directly using sendfile.

Run locally

Linux (or WSL2) is required because of epoll and sendfile.

# Build
ulimit -n 65535

g++ server.cpp -o server -pthread -std=c++17

# Run
./server

Open the UI:

• http://localhost:8080/

Useful endpoints

• / - UI page
• /stats - JSON stats for the dashboard
• /upload - POST endpoint for file upload demo
• /time - CGI demo (calls time_server.py)
• DELETE /uploaded_data.txt - delete demo file

Stress testing

The UI has a "Live Stress Test" button. It calls:

/trigger-stress?count=500

The server uses curl + xargs -P 100 to generate parallel requests from the server host itself. This avoids browser connection limits, so the dashboard counter jumps quickly.

Notes:

• The stress test is meant for local use only.
• Railway and similar platforms have rate limits. The UI caps stress-test options when deployed on Railway.

Limitations (by design)

• No TLS/HTTPS
• No HTTP/2 or HTTP/3
• No virtual hosts
• No compression
• No access logs or rotation

Deployment

And this http server is deployed in Railway.

Architecture diagram

flowchart TD
	A["Clients (10k plus)"] -->|"TCP connection"| B["Main thread - epoll wait"]
	B -->|"New connection?"| C["Accept and set non blocking"]
	B -->|"Data ready?"| D["Remove from epoll and enqueue task"]
	D --> E["Thread pool queue"]
	E --> F["Worker thread 1"]
	E --> G["Worker thread 2"]
	E --> H["Worker thread 3"]
	E --> I["Worker thread 4"]
	F -->|"Process request"| J["Task type"]
	J -->|"Static file"| K["Zero copy sendfile"]
	J -->|"Dynamic content"| L["CGI fork exec"]
	K --> M["Send response and close"]
	L --> M

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If you want to dig into the internals, start with server.cpp and HttpParser.h.