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")

Thank you so much for sharing this great code. I'm currently porting it to Swift and it's going well, but I'm wondering if I've spotted a bug: As I understand it, the "MX: 3" header means that devices will wait a random delay between 0 and 3 seconds before responding, but the default timeout is 2 seconds, so that seems destined to miss some devices that chose a high delay?

Just saying thanks for the code, I am using it in Kodi (OSMC) to launch Netflix and Youtube app directly in my Smart TV using DIAL APIs

@dankrause - thanks for this code, it's a great implementation. I've added Python 3 compatibility and included it in a library for talking to Doxie document scanners.

Here's the Swift port I mentioned in case it's of any use to anyone.

@JJC1138 - I've made the same observation myself; I think it would be better if the default timeout were set to something like 5 to accommodate the potential worst case response delay.

Python 3 version:

From f81513300e2233d3d2a42fa90dcd60fb52351149 Mon Sep 17 00:00:00 2001
From: Adam Baxter <[email protected]>
Date: Sat, 10 Dec 2016 15:44:49 +1100
Subject: [PATCH] Python 3 version

---
 ssdp.py | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/ssdp.py b/ssdp.py
index acd330a..4a96bf7 100644
--- a/ssdp.py
+++ b/ssdp.py
@@ -1,4 +1,4 @@
-#   Copyright 2014 Dan Krause
+#   Copyright 2014 Dan Krause, Python 3 hack 2016 Adam Baxter
 #
 #   Licensed under the Apache License, Version 2.0 (the "License");
 #   you may not use this file except in compliance with the License.
@@ -13,15 +13,15 @@
 #   limitations under the License.
 
 import socket
-import httplib
-import StringIO
+import http.client
+import io
 
 class SSDPResponse(object):
-    class _FakeSocket(StringIO.StringIO):
+    class _FakeSocket(io.BytesIO):
         def makefile(self, *args, **kw):
             return self
     def __init__(self, response):
-        r = httplib.HTTPResponse(self._FakeSocket(response))
+        r = http.client.HTTPResponse(self._FakeSocket(response))
         r.begin()
         self.location = r.getheader("location")
         self.usn = r.getheader("usn")
@@ -43,14 +43,16 @@ def discover(service, timeout=5, retries=1, mx=3):
         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)
+        message_bytes = message.format(*group, st=service, mx=mx).encode('utf-8')
+        sock.sendto(message_bytes, group)
+
         while True:
             try:
                 response = SSDPResponse(sock.recv(1024))
                 responses[response.location] = response
             except socket.timeout:
                 break
-    return responses.values()
+    return list(responses.values())
 
 # Example:
 # import ssdp
-- 
2.10.1.windows.1

I use your code, but it keeps timing out. Could you please give any advice for debugging? Im using ubuntu trying to discover a sony alpha 6000 camera

Thanks for this code. Using it on https://github.com/pedrinho/samsung_remote to find Samsung TV's on network and works like a charme!

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,