rod rod - 1 month ago 10
Node.js Question

Formatting messages to send to socket.io node.js server from python client

I'm trying to get a Python client talking to a Node.js server using Socket.io 0.7, by sending a custom event to the server.

Based on the Socket.io reference I have found on GitHub, and the following WebSocket Python library.

Here's is my code so far:

Node server

io.sockets.on('connection', function (socket) {
socket.on('newimg', function(data) {
console.log(data);
});
});


Python client

def handshake(host, port):
u = urlopen("http://%s:%d/socket.io/1/" % (host, port))
if u.getcode() == 200:
response = u.readline()
(sid, hbtimeout, ctimeout, supported) = response.split(":")
supportedlist = supported.split(",")
if "websocket" in supportedlist:
return (sid, hbtimeout, ctimeout)
else:
raise TransportException()
else:
raise InvalidResponseException()


try:
(sid, hbtimeout, ctimeout) = handshake(HOSTNAME, PORT) #handshaking according to socket.io spec.
Except Exception as e:
print e
sys.exit(1)
ws = websocket.create_connection("ws://%s:%d/socket.io/1/websocket/%s" % (HOSTNAME, PORT, sid))
print ws.recv()
ws.send("2::")
ws.send("5:1::{'name':'newimg', 'args':'bla'}")
print ws.recv()
print "Closing connection"
ws.close()


Node console output

debug - client authorized
info - handshake authorized 12738935571241622933
debug - setting request GET /socket.io/1/websocket/12738935571241622933
debug - set heartbeat interval for client 12738935571241622933
debug - client authorized for
debug - websocket writing 1::
debug - websocket received data packet 2::
debug - got heartbeat packet
debug - websocket received data packet 5:1::{'name':'newimg', 'args':'bla'}
debug - acknowledging packet automatically
debug - websocket writing 6:::1
info - transport end
debug - set close timeout for client 12738935571241622933
debug - cleared close timeout for client 12738935571241622933
debug - cleared heartbeat interval for client 12738935571241622933
debug - discarding transport


Python console output

Done
1::
6:::1
Closing connection


Now it seems the socket event is not being triggered, despite the server responding with ACK. So the message is being correctly received but I am assuming, not formatted properly for socket.io to trigger an event.

I didn't think framing was necessary, however Archie1986 seems to disagree on his response to this: Socket.IO Client Library in Python

What might I be doing wrong here?

rod rod
Answer

Resolved. I needed to use double quotes. Single quotes are not valid JSON. Woops.

ws.send("5:1::{'name':'newimg', 'args':'bla'}")

Becomes:

ws.send('5:1::{"name":"newimg", "args":"bla"}')