DIAL examples

discover.py

import httplib
import socket
import StringIO

# generic
SSDP_ALL = 'ssdp:all'
UPNP_ROOT = 'upnp:rootdevice'

# devices
DIAL = 'urn:dial-multiscreen-org:service:dial:1'


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._headers = r.getheaders()
        self.location = r.getheader('location')
        self.usn = r.getheader('usn')
        self.st = r.getheader('st')
        self.server = r.getheader('server')
        self.cache = r.getheader('cache-control').split('=')[1]

    def __repr__(self):
        return '<SSDPResponse({location}, {st}, {usn})'.format(**self.__dict__)


def discover(st, timeout=2, retries=1):

    group = ('239.255.255.250', 1900)

    message = '\r\n'.join([
        'M-SEARCH * HTTP/1.1',
        'HOST: {0}:{1}'.format(*group),
        'MAN: "ssdp:discover"',
        'ST: {st}','MX: 3','',''])

    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(st=st), group)

        while 1:
            try:
                response = SSDPResponse(sock.recv(1024))
                responses[response.location] = response
            except socket.timeout:
                break

    return responses.values()


if __name__ == '__main__':
    for device in discover(SSDP_ALL, timeout=5):
        print "%s\n\t%s" % (device.location, device.server)

"""
DLNA_RENDERER = 'urn:schemas-upnp-org:device:MediaRenderer:1'
DLNA_SERVER = 'urn:schemas-upnp-org:device:MediaServer:1'
GATEWAY = 'urn:schemas-upnp-org:device:InternetGatewayDevice:1'
PANASONIC_VIERA = 'urn:panasonic-com:device:p00RemoteController:1'
ROKU = 'roku:ecp'
SONOS = 'urn:schemas-upnp-org:device:ZonePlayer:1'
SONY_NEX = 'urn:schemas-sony-com:service:ScalarWebAPI:1'
WAN_IP = 'urn:schemas-upnp-org:service:WANIPConnection:1'
WAN_PPP = 'urn:schemas-upnp-org:service:WANPPPConnection:1'
"""

howitworks.md

Things you don't want to have to know just to watch Hot Rod

From your phone or tablet to your TV

• AirPlay
• Chromecast + related technologies

Discovery with SSDP

Simple Service Discovery Protocol (SSDP) is used to discover services advertised by devices on your network.

• Yell "who's out there?!"
• Listen for responses

Launching apps and playing media with DIAL

Discovery And Launch (DIAL) is a simple protocol that 2nd screen devices can use to launch apps on 1st screen devices. Developed by Netflix and YouTube.

• Find device's DIAL endpoint
• Use it

Name registry

Incredibly high-tech, Google Spreadsheet powered name registry.

DIAL Protocol

Overview of the DIAL protocol.

UPnP > DIAL > Chromecast

1. Send multicast M-SEARCH request with a Search Target (ST) header of urn:dial-multiscreen-org:service:dial:1.
2. Read LOCATION header of responding GET requests.
3. GET the LOCATION header and read the APPLICATION-URL header in the response.
4. APP-URL is /, where APP-NAME is defined in the registry.
5. POST to APP-URL. Include supported parameters in the body of the POST, if necessary. v=eIej8JgWWJk is a good demo for YouTube.
6. Read the LOCATION header of the POST response to get the INSTANCE-URL.
7. DELETE to the INSTANCE-URL to stop the running app.

YouTube

• Play a video:

    {"v": video_id}
  

• Play a playlist:

    {"listType": "playlist", "list": playlist_id}
  

Thanks for sharing, this was very useful!

I tried the YouTube JSON parameters as in your example and they don't work, I'm only able to get it working by sending a raw body, for example: v=DYd57rkvnpQ