Tinyhttpd
Ultra-lightweight Http Server with less than 500 lines in 1999
Tinyhttpd is an educational HTTP server originally written in C by J. David Blackstone in 1999. Its implementation is under roughly 500 lines, making the entire request lifecycle small enough to study directly. The server opens a socket, accepts browser connections, parses HTTP methods and URLs, and serves files from an htdocs directory. It handles GET and POST requests and can execute CGI programs through Unix pipes and child processes. The code includes responses for bad requests, missing files, unsupported methods, and CGI failures. ...