A simple python HTTP server that either serves as a proxy or as an echo server. If working as an echo server, it outputs the headers and body into log output and to the client, which is useful when debugging a reverse proxy or caching server to see what is being sent. If working as a proxy server, it outputs what the request headers will be to t…

http_echo_and_proxy_server.py

#!/usr/bin/env python

from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer
import StringIO
import argparse
import logging
import os
import random
import sys
import urllib2

logging.basicConfig()

logger = logging.getLogger(__name__)

class EchoHTTPRequestHandler(BaseHTTPRequestHandler):
    def do_HEAD(self):
        self.do_GET(method='HEAD', body=False)
    
    def do_GET(self, method='GET', body=True):
        try:
            try:
                sio = StringIO.StringIO()
                sio.write('====BEGIN REQUEST=====\n')
                sio.write(self.command)
                sio.write(' ')
                sio.write(self.path)
                sio.write(' ')
                sio.write(self.request_version)
                sio.write('\n')
                for line in self.headers.headers:
                    sio.write(line)
                sio.write('\n')
                #if self.rfile:
                #    sio.write(self.rfile.read())
                sio.write('\n')
                sio.write('====END REQUEST=======\n')
                logger.info(sio.getvalue())
                
                self.send_response(200)
                self.send_header('Content-Type', 'text/plain')
                self.send_header('Content-Length', str(len(sio.getvalue())))
                self.end_headers()
                if body:
                    self.wfile.write(sio.getvalue())
                return
            finally:
                sio.close()
        except IOError:
            self.send_error(404, 'file not found')
    

#

class ProxyHTTPRequestHandler(BaseHTTPRequestHandler):
    def do_HEAD(self):
        self.do_GET(body=False)
    
    def do_GET(self, body=True):
        sent = False
        try:
            req = None
            resp = None
            sio = StringIO.StringIO()
            try:
                hostname = self.headers.getheader('Host')
                if not hostname:
                    hostname = 'localhost'
                url = 'http://{}{}'.format(hostname, self.path)
                req = urllib2.Request(url=url)
                sio.write('====BEGIN REQUEST=====\n')
                sio.write(url)
                sio.write('\n')
                sio.write(self.command)
                sio.write(' ')
                sio.write(self.path)
                sio.write(' ')
                sio.write(self.request_version)
                sio.write('\n')
                for line in self.headers.headers:
                    line_parts = [o.strip() for o in line.split(':', 1)]
                    if len(line_parts) == 2:
                        if line_parts[0].startswith('X-'):
                            pass
                        elif line_parts[0] in ('Connection','User-Agent'):
                            pass
                        else:
                            sio.write(line)
                            req.add_header(*line_parts)
                sio.write('\n')
                sio.write('====END REQUEST=======\n')
                logger.error(sio.getvalue())
                try:
                    resp = urllib2.urlopen(req)
                except urllib2.HTTPError as e:
                    if e.getcode():
                        resp = e
                    else:
                        self.send_error(599, u'error proxying: {}'.format(unicode(e)))
                        sent = True
                        return
                self.send_response(resp.getcode())
                respheaders = resp.info()
                for line in respheaders.headers:
                    line_parts = line.split(':', 1)
                    if len(line_parts) == 2:
                        self.send_header(*line_parts)
                self.end_headers()
                sent = True
                if body:
                    self.wfile.write(resp.read())
                return
            finally:
                if resp:
                    resp.close()
                sio.close()
        except IOError as e:
            if not sent:
                self.send_error(404, 'error trying to proxy: {}'.format(str(e)))

def parse_args(argv=sys.argv[1:]):
    parser = argparse.ArgumentParser(description='Either Proxy or Echo HTTP requests')
    parser.add_argument('--port', dest='port', type=int, default=random.randint(20000, 60000),
                       help='serve HTTP requests on specified port (default: random)')
    parser.add_argument('--type', dest='server_type', choices=['echo', 'proxy'], default='echo',
                      help='Whether to run as a proxy server or echo server')
    args = parser.parse_args(argv)
    return args

def main(argv=sys.argv[1:]):
    args = parse_args(argv)
    print('http server is starting on port {}...'.format(args.port))
    server_address = ('127.0.0.1', args.port)
    if args.server_type == 'proxy':
        httpd = HTTPServer(server_address, ProxyHTTPRequestHandler)
    else:
        httpd = HTTPServer(server_address, EchoHTTPRequestHandler)
    print('http server is running as {}...'.format(args.server_type))
    httpd.serve_forever()
    
if __name__ == '__main__':
    main()