DLNA Proxy (including SSDP and Multicast)

dlna_proxy.py

import socket, thread, sys
import logging

BUFLEN = 1024

logger = logging.getLogger(__name__)

class DLNAProxy(object):
    MEDIASERVER_IP = ""
    
    def __init__(self, connection, address, timeout):
        try:
            logger.debug("new connection handler")
        
            self.client = connection
            self.client_buffer = ''
            self.timeout = timeout
        
            # connect to target server
            (soc_family, _, _, _, address) = socket.getaddrinfo(self.MEDIASERVER_IP, 5001)[0]
            self.target = socket.socket(soc_family)
            self.target.connect(address)

            # get request
            request = "".join([part[1] for part in self.read_response(self.client)])
            request2 = request.replace("192.168.178.001", self.MEDIASERVER_IP)
            logger.debug("--------------------------------------------")
            logger.debug(request)
            logger.debug("--------------------------------------------")
        
            # send request to target server
            self.target.send(request2)
            
            # read response
            for text_content, response_part in self.read_response(self.target):
                if text_content:
                    self.client.send(response_part.replace(self.MEDIASERVER_IP, "192.168.178.001"))
                else:
                    self.client.send(response_part)

            self.client.close()
            self.target.close()
        except:
            logger.exception("Something went wrong")

    def read_response(self, read_socket):
        buffer = ""
        socket_file = read_socket.makefile()
        content_length = 0
        text_content = False
        while 1:
            line = socket_file.readline()
            buffer += line
            if "Content-Length" in line:
                content_length = int(line.split()[1])
            if "Content-Type" in line:
                text_content = "text/xml" in line
            if line == "\r\n":
                break
        logger.debug("Read header: %d", content_length)
        yield True, buffer
        if content_length > 1024*1024:
            data_part = socket_file.read(8*1024)
            while data_part:
                yield text_content, data_part
                data_part = socket_file.read(8*1024)
        else:
            yield text_content, socket_file.read(content_length)

class DLNAMulticastHelper(object):
    MCAST_GRP = '239.255.255.250'
    MCAST_PORT = 1900
    
    def __init__(self, mediaserver_ip):
        self.mediaserver_ip = mediaserver_ip
    
    def run(self):
        sock_send = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
        sock_send.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 2)
        sock_send.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        sock_send.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_IF, socket.inet_aton("192.168.178.1"))

        sock_recv = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
        sock_recv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        sock_recv.setsockopt(socket.SOL_IP, socket.IP_ADD_MEMBERSHIP, socket.inet_aton(self.MCAST_GRP)+socket.inet_aton("192.168.179.1"))
        sock_recv.bind((self.MCAST_GRP, self.MCAST_PORT))

        while True:
            dgram, addr = sock_recv.recvfrom(10240)
            dgram2 = dgram.replace(self.mediaserver_ip, "192.168.178.1")
            sock_send.sendto(dgram2, (self.MCAST_GRP, self.MCAST_PORT))


if __name__ == '__main__':
    logging.basicConfig()

    # start multicast helper
    multi_helper = DLNAMulticastHelper(sys.argv[1])
    thread.start_new_thread(multi_helper.run, tuple())

    # start HTTP proxy
    DLNAProxy.MEDIASERVER_IP = sys.argv[1]
    soc = socket.socket(socket.AF_INET)
    soc.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    soc.bind(("192.168.178.1", 5001))
    soc.listen(0)
    while 1:
        thread.start_new_thread(DLNAProxy, soc.accept()+(60,))

Can you explain a little here please, it's really interesting your code :D

Anybody got the script to work ?
What is the local IP, and where is the IP of the "remote" DLNA server ?
With python3 it fails on:

dgram2 = dgram.replace(self.mediaserver_ip, "aaa.bbb.ccc.ddd")
TypeError: a bytes-like object is required, not 'str'

At first glance, I see that you hard-coded the IP 192.168.* at multiple locations. You could probably do a DRY refactoring here?

yeah probably, but the IP isn't changing in my setup so doesn't really help me

Can you explain a little here please, it's really interesting your code :D

The code binds to the local multicast interface that DLNA uses to communicate and proxies any requests towards the real mediaserver (using a unicast connection). In the response it replaces the media server IPs with the local ones (and visa-versa on the first leg).

Anybody got the script to work ? What is the local IP, and where is the IP of the "remote" DLNA server ? With python3 it fails on:

dgram2 = dgram.replace(self.mediaserver_ip, "aaa.bbb.ccc.ddd") TypeError: a bytes-like object is required, not 'str'

Assuming you have a different home network layout, you need to replace all references to 192.168.17[89].1 to IPs that fit your setup (those are the IPs used by the proxy not the server). Then you should be able to run this with python2 and providing the IP of your mediaserver as argument, e.g. python2 dlna_proxy.py 192.168.200.10

This had been developed on python2, so adjustments are needed to make it work on python3 (as the error you encountered confirms).