Tiny python SSDP discovery library with no external dependencies

ssdp.py

#   Copyright 2014 Dan Krause
#
#   Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.

import socket
import httplib
import StringIO

class SSDPResponse(object):
    class _FakeSocket(StringIO.StringIO):
        def makefile(self, *args, **kw):
            return self
    def __init__(self, response):
        r = httplib.HTTPResponse(self._FakeSocket(response))
        r.begin()
        self.location = r.getheader("location")
        self.usn = r.getheader("usn")
        self.st = r.getheader("st")
        self.cache = r.getheader("cache-control").split("=")[1]
    def __repr__(self):
        return "<SSDPResponse({location}, {st}, {usn})>".format(**self.__dict__)

def discover(service, timeout=5, retries=1, mx=3):
    group = ("239.255.255.250", 1900)
    message = "\r\n".join([
        'M-SEARCH * HTTP/1.1',
        'HOST: {0}:{1}',
        'MAN: "ssdp:discover"',
        'ST: {st}','MX: {mx}','',''])
    socket.setdefaulttimeout(timeout)
    responses = {}
    for _ in range(retries):
        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 2)
        sock.sendto(message.format(*group, st=service, mx=mx), group)
        while True:
            try:
                response = SSDPResponse(sock.recv(1024))
                responses[response.location] = response
            except socket.timeout:
                break
    return responses.values()

# Example:
# import ssdp
# ssdp.discover("roku:ecp")

I've run this successfully on a Fedora machine and can't get it to find any rokus on an Ubuntu machine. Both on the same network both wirelessly connected. Don't understand why it would discover rokus on one and not the other. Anyone else had this issue?

Hi,

Great bit of code. I've been chasing a real gssdp / gupnp problem and are wondering how easy it would be to turn this code into a M-SEARCH listener? I need to prove that my Linux gssdp/gupnp libraries are actually doing their job. Rygel which uses theses libs seems to miss a lot of SSDP searches from various apps like iPad MConnect. Big question is that do the python libs use the same libraries as a bottom end.

Thanks,