Hi,

I am implementing a code through which i have to get devices connected to all network interfaces on my machine and list them .

For this, i am first getting the ip of all network interfaces and then sending m-search command on them.

After 2.5 seconds port is stopped to listen.

But it is giving me some assertion error. (I am connected to 2 interfaces -ethernet and wifi)

`Code:`

class Base(DatagramProtocol):

""" Class to send M-SEARCH message to devices in network and receive datagram

packets from them

"""

SSDP_ADDR = "239.255.255.250"

SSDP_PORT = 1900

MS = "M-SEARCH * HTTP/1.1\r\nHOST: {}:{}\r\nMAN: 'ssdp:discover'\r\nMX: 2\r\nST: ssdp:all\r\n\r\n".format(SSDP_ADDR, SSDP_PORT)

def sendMsearch(self):

""" Sending M-SEARCH message

"""

ports = []

for address in self.addresses:

ports.append(reactor.listenUDP(0, self, interface=address))

for port in ports:

for num in range(4):

port.write(Base.MS, (Base.SSDP_ADDR,Base.SSDP_PORT))

reactor.callLater(2.5, self.stopMsearch, port) # MX + a wait margin

def stopMsearch(self, port):

""" Stop listening on port

"""

port.stopListening()

`Error:`

Traceback (most recent call last):

File "work\find_devices.py", line 56, in sendMsearch

ports.append(reactor.listenUDP(0, self, interface=address))

File "C:\Python27\lib\site-packages\twisted\internet\posixbase.py", line 374, in listenUDP

p.startListening()

File "C:\Python27\lib\site-packages\twisted\internet\udp.py", line 172, in startListening

self._connectToProtocol()

File "C:\Python27\lib\site-packages\twisted\internet\udp.py", line 210, in _connectToProtocol

self.protocol.makeConnection(self)

File "C:\Python27\lib\site-packages\twisted\internet\protocol.py", line 709, in makeConnection

assert self.transport == None

AssertionError

This code worked:

def sendMsearch(self):

""" Sending M-SEARCH message

"""

address = socket.gethostbyname(socket.gethostbyname())

port = reactor.listenUDP(0, self, interface=address)
for num in range(4):

port.write(Base.MS, (Base.SSDP_ADDR,Base.SSDP_PORT))

reactor.callLater(2.5, self.stopMsearch, port) # MX + a wait margin

Please tell what's wrong in code mentioned in the start of this mail and how to correct this.

I have also posted this code on stackoverflow , but didn't get any response