Simple HTTP Server

Purpose Build a very straightforward http server in order to understand better how http really works under the hood. This is also because I want to learn a bit of C in the process, so it's very likely there's going to be a lot of bad code and weird patterns

Phase 1: Serve static HTML page

Build enough so that a static HTML content can be served through GET /. No multi-threads, nothing fancy

• Create a server that can listen to HTTP requests and dumps the raw request into stdout
• Read method, path, and HTTP version from request
• Send a hard coded response with a 200 OK status and mock HTML
• Read and parse headers from request
• Minimal router: GET / returns HTML, POST /echo parses the request and sends back the body as the response. Any other route should come back as 404 Not Found
• Keep the server running and processing requests

Phase 2: Make it technically correct

Improve correctness without turning this into a production server.

• Detect end of headers using \r\n\r\n instead of naive splitting
• Parse request only after full headers are received
• Read body strictly based on Content-Length
• Support request bodies larger than the initial buffer (multiple read() calls)
• Add Content-Length header to all responses
• Return 400 Bad Request for malformed request lines
• Return 405 Method Not Allowed for unsupported methods
• Run with sanitizers (ASan/LSan) and fix memory issues
• Stop unnecessary strdup calls and parse request in-place when possible

Phase 3: Serve real static files

Serve files inside a www/ directory.

• Serve files from a www/ directory (e.g. GET /index.html -> ./www/index.html)
• Default route: GET / serves ./www/index.html
• Return 404 Not Found when file does not exist
• AddContent-Type support by extension
• Prevent path traversal
• Stream file contents to the socket (do not load entire file into memory)

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