Putting It All Together

You now have every piece. The full server is a state machine on top of TCP:

listen(port)
loop:
    conn = accept()
    spawn handle_connection(conn):
        while True:
            request = parse_request(conn)         # request line + headers + body
            if not request: break                  # malformed or EOF
            handler = router.match(request)
            response = handler(request)
            response.headers["Date"] = now_rfc1123()
            response.headers["Server"] = "MyServer/1.0"
            send_response(conn, response)
            access_log(request, response)
            metrics.record(request, response)
            if should_close(request, response): break
        close(conn)

What separates a hobby implementation from production:

• Timeouts everywhere: idle, read, write, total request. Without these, one slow client can hold a worker forever.
• Graceful shutdown: SIGTERM -> stop accepting -> drain in-flight requests -> exit. Lets a load balancer remove you cleanly.
• Limits: max header size (8 KB), max body size (configurable), max request line length (8 KB), max headers per request (~100).
• TLS: in production you serve HTTPS, not HTTP. Termination usually happens at a load balancer (nginx, envoy, AWS ALB).
• HTTP/2: completely different framing — binary, multiplexed, server-push. HTTP/3 runs over QUIC. The above design is HTTP/1.1 only.

You now know how nginx, Apache, Caddy, and Go's net/http actually work.