#!/usr/bin/env python3 """Simple HTTP server that responds 200 with a test message including client IP. Behavior: - GET returns HTTP/1.1 200 with a message including the requester IP - HEAD returns the same headers as GET but no body - Displays whether any incoming X-* headers were detected and lists them - If User-Agent contains "curl" or "wget" (case-insensitive) the server responds with Content-Type: text/plain; otherwise Content-Type: text/html. - --look controls which HTML variant is returned for non-CLI agents: * basic - plain HTML with no external references * nice - includes Google Font "Noto Sans" (default) * bootstrap - Bootstrap 5 layout * tailwind - Tailwind CSS via @tailwindcss/browser@latest - The URL query parameter "look" (e.g. /?look=nice) overrides the command-line --look for that request only. Values are case-insensitive and must be one of basic,nice,bootstrap,tailwind. Usage: python3 ok_server.py # binds 0.0.0.0:8080, nice look python3 ok_server.py --look basic python3 ok_server.py -b 127.0.0.1 -p 8080 --look tailwind Test: curl -i http://localhost:8080/ # text/plain for curl curl -i "http://localhost:8080/?look=basic" # request-level override curl -I http://localhost:8080/ # HEAD (headers only) wget -S -O - http://localhost:8080/ # text/plain for wget open http://localhost:8080/ # browser gets HTML variant per look """ import argparse import signal import sys from html import escape from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer from typing import Tuple from urllib.parse import urlparse, parse_qs PLAIN_TEMPLATE = ( "Hello, This is a test HTTP server.\n\n" "Your request came from {ip}.\n\n" "{proxy_headers_block}" "Have a nice day!\n" ) HTML_BASIC = """ Test HTTP server

Hello,

This is a test HTTP server.

Your request came from {ip_html}.

{proxy_headers_html}

Have a nice day!

""" HTML_NICE = """ Test HTTP server

Hello,

This is a test HTTP server.

Your request came from {ip_html}.

{proxy_headers_html}

Have a nice day!

""" HTML_BOOTSTRAP = """ Test HTTP server

Hello,

This is a test HTTP server.

Your request came from {ip_html}.

{proxy_headers_html}

Have a nice day!

""" HTML_TAILWIND = """ Test HTTP server

Test HTTP server

Simple status page for firewall/testing

Hello,

This is a test HTTP server.

Your request came from {ip_html}.

{proxy_headers_html}

Have a nice day!

""" VALID_LOOKS = ("basic", "nice", "bootstrap", "tailwind") class OkHandler(BaseHTTPRequestHandler): protocol_version = "HTTP/1.1" def _collect_x_headers(self): x_headers = [] for name, value in self.headers.items(): if name.lower().startswith("x-"): x_headers.append((name, value)) return sorted(x_headers, key=lambda item: item[0].lower()) def _proxy_markup(self, x_headers): if not x_headers: return "", "" plain_lines = [f" - {name}: {value}" for name, value in x_headers] proxy_headers_block = ( "Reverse proxy condition: detected via X-* headers.\n" "X-* headers:\n" + "\n".join(plain_lines) + "\n\n" ) html_items = "".join( [f"
  • {escape(name)}: {escape(value)}
    • " for name, value in x_headers] ) proxy_headers_html = ( "

    Reverse proxy condition: detected via X-* headers.

    " "

    X-* headers:

    " ) return proxy_headers_block, proxy_headers_html def _is_cli_agent(self, ua: str) -> bool: if not ua: return False ua_l = ua.lower() return ("curl" in ua_l) or ("wget" in ua_l) def _get_request_look(self) -> str: """Return look from URL query (if valid) or None.""" # parse query string from the request path parsed = urlparse(self.path) qs = parse_qs(parsed.query) look_vals = qs.get("look") if not look_vals: return None # use first value, case-insensitive look = look_vals[0].strip().lower() if look in VALID_LOOKS: return look return None def _html_for_look(self, look: str, ip_html: str, proxy_headers_html: str) -> str: if look == "basic": return HTML_BASIC.format( ip_html=ip_html, proxy_headers_html=proxy_headers_html, ) if look == "nice": return HTML_NICE.format( ip_html=ip_html, proxy_headers_html=proxy_headers_html, ) if look == "bootstrap": return HTML_BOOTSTRAP.format( ip_html=ip_html, proxy_headers_html=proxy_headers_html, ) # fallback to tailwind return HTML_TAILWIND.format( ip_html=ip_html, proxy_headers_html=proxy_headers_html, ) def _make_body_and_type(self, client_ip: str, user_agent: str) -> Tuple[bytes, str]: x_headers = self._collect_x_headers() proxy_headers_block, proxy_headers_html = self._proxy_markup(x_headers) xff = self.headers.get("X-Forwarded-For", "") if xff: real_ip = xff.split(",")[0].strip() # strip port: [::1]:port -> ::1, 1.2.3.4:port -> 1.2.3.4 if real_ip.startswith("["): real_ip = real_ip[1:real_ip.index("]")] if "]" in real_ip else real_ip[1:] elif real_ip.count(":") == 1: real_ip = real_ip.split(":")[0] ip_text = f"{real_ip} (forwarded by proxy {client_ip})" ip_html = ( f"{escape(real_ip)}" f" (forwarded by proxy {escape(client_ip)})" ) else: ip_text = client_ip ip_html = f"{escape(client_ip)}" if self._is_cli_agent(user_agent): body = PLAIN_TEMPLATE.format( ip=ip_text, proxy_headers_block=proxy_headers_block, ).encode("utf-8") ctype = "text/plain; charset=utf-8" return body, ctype # Check request-level override first request_look = self._get_request_look() if request_look: look = request_look else: # fallback to server-level default (now: nice) look = getattr(self.server, "look", "nice") html = self._html_for_look(look, ip_html, proxy_headers_html) body = html.encode("utf-8") ctype = "text/html; charset=utf-8" return body, ctype def _send_ok_headers(self, content_type: str, body_len: int): self.send_response(200) self.send_header("Content-Type", content_type) self.send_header("Content-Length", str(body_len)) self.end_headers() def do_GET(self): client_ip = self.client_address[0] user_agent = self.headers.get("User-Agent", "") body, ctype = self._make_body_and_type(client_ip, user_agent) try: self._send_ok_headers(ctype, len(body)) self.wfile.write(body) except BrokenPipeError: # client closed connection early; ignore pass def do_HEAD(self): client_ip = self.client_address[0] user_agent = self.headers.get("User-Agent", "") body, ctype = self._make_body_and_type(client_ip, user_agent) # send same headers as GET but no body self._send_ok_headers(ctype, len(body)) # minimal single-line log to stderr def log_message(self, format, *args): sys.stderr.write("%s - - [%s] %s\n" % (self.client_address[0], self.log_date_time_string(), format % args)) def run(bind: str, port: int, look: str): addr = (bind, port) try: with ThreadingHTTPServer(addr, OkHandler) as httpd: def _handle_termination(signum, _frame): _ = signum raise KeyboardInterrupt signal.signal(signal.SIGINT, _handle_termination) signal.signal(signal.SIGTERM, _handle_termination) # attach chosen look to server so handlers can use it as default httpd.look = look print(f"Serving on {bind}:{port} (default look={look}) (Ctrl-C to stop)") httpd.serve_forever() except KeyboardInterrupt: print("\nShutting down server") except Exception as e: print("Server error:", e, file=sys.stderr) raise if __name__ == "__main__": parser = argparse.ArgumentParser(description="HTTP OK test server") parser.add_argument("-b", "--bind", default="0.0.0.0", help="Address to bind to (default: 0.0.0.0)") parser.add_argument("-p", "--port", type=int, default=8080, help="Port to listen on (default: 8080)") parser.add_argument("--look", choices=VALID_LOOKS, default=VALID_LOOKS[1], help="Default HTML look for non-cli agents (basic, nice, bootstrap, tailwind). Default: nice") args = parser.parse_args() run(args.bind, args.port, args.look)