How do I write a python HTTP server to listen on multiple ports?

Question

I'm writing a small web server in Python, using BaseHTTPServer and a custom subclass of BaseHTTPServer.BaseHTTPRequestHandler. Is it possible to make this listen on more than one port?

What I'm doing now:

class MyRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
  def doGET
  [...]

class ThreadingHTTPServer(ThreadingMixIn, HTTPServer): 
    pass

server = ThreadingHTTPServer(('localhost', 80), MyRequestHandler)
server.serve_forever()

Answer 1

Sure; just start two different servers on two different ports in two different threads that each use the same handler. Here's a complete, working example that I just wrote and tested. If you run this code then you'll be able to get a Hello World webpage at both http://localhost:1111/ and http://localhost:2222/

from threading import Thread
from SocketServer import ThreadingMixIn
from BaseHTTPServer import HTTPServer, BaseHTTPRequestHandler

class Handler(BaseHTTPRequestHandler):
    def do_GET(self):
        self.send_response(200)
        self.send_header("Content-type", "text/plain")
        self.end_headers()
        self.wfile.write("Hello World!")

class ThreadingHTTPServer(ThreadingMixIn, HTTPServer):
    pass

def serve_on_port(port):
    server = ThreadingHTTPServer(("localhost",port), Handler)
    server.serve_forever()

Thread(target=serve_on_port, args=[1111]).start()
serve_on_port(2222)

update:

This also works with Python 3 but three lines need to be slightly changed:

from socketserver import ThreadingMixIn
from http.server import HTTPServer, BaseHTTPRequestHandler

and

self.wfile.write(bytes("Hello World!", "utf-8"))

Answer 2

I would say that threading for something this simple is overkill. You're better off using some form of asynchronous programming.

Here is an example using Twisted:

from twisted.internet import reactor
from twisted.web import resource, server

class MyResource(resource.Resource):
    isLeaf = True
    def render_GET(self, request):
        return 'gotten'

site = server.Site(MyResource())

reactor.listenTCP(8000, site)
reactor.listenTCP(8001, site)
reactor.run()

I also thinks it looks a lot cleaner to have each port be handled in the same way, instead of having the main thread handle one port and an additional thread handle the other. Arguably that can be fixed in the thread example, but then you're using three threads.

Answer 3

Not easily. You could have two ThreadingHTTPServer instances, write your own serve_forever() function (don't worry it's not a complicated function).

The existing function:

def serve_forever(self, poll_interval=0.5):
    """Handle one request at a time until shutdown.

    Polls for shutdown every poll_interval seconds. Ignores
    self.timeout. If you need to do periodic tasks, do them in
    another thread.
    """
    self.__serving = True
    self.__is_shut_down.clear()
    while self.__serving:
        # XXX: Consider using another file descriptor or
        # connecting to the socket to wake this up instead of
        # polling. Polling reduces our responsiveness to a
        # shutdown request and wastes cpu at all other times.
        r, w, e = select.select([self], [], [], poll_interval)
        if r:
            self._handle_request_noblock()
    self.__is_shut_down.set()

So our replacement would be something like:

def serve_forever(server1,server2):
    while True:
        r,w,e = select.select([server1,server2],[],[],0)
        if server1 in r:
            server1.handle_request()
        if server2 in r:
            server2.handle_request()