I've just been working through the erlang websockets example from Joe Armstrong's blog I'm still quite new to erlang so I decided to write a simple server in python that would help teach me about websockets (and hopefully some erlang by interpreting joe's code). I'm having two issues:
1) Data I receive from the page includes a 'ÿ' as the last char. This doesn't appear in the erlang version and I can't work out where it's coming from Fixed - This was because the strings where encoded in utf-8 and I wasn't decoding them
2) I seem to be sending data from the server (through the websocket) - which can be confirmed by looking at how many bytes client.send() makes. But nothing is appearing on the page. Fixed, I wasn't encoding the string correctly
I've put all the code here. Here's my python version incase i'm missing anything obvious
import threading
import socket
def start_server():
tick = 0
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.bind(('localhost', 1234))
sock.listen(100)
while True:
print 'listening...'
csock, address = sock.accept()
tick+=1
print 'connection!'
handshake(csock, tick)
print 'handshaken'
while True:
interact(csock, tick)
tick+=1
def handshake(client, tick):
our_handshake = "HTTP/1.1 101 Web Socket Protocol Handshake\r\n"+"Upgrade: WebSocket\r\n"+"Connection: Upgrade\r\n"+"WebSocket-Origin: http://localhost:8888\r\n"+"WebSocket-Location: "+" ws://localhost:1234/websession\r\n\r\n"
shake = client.recv(255)
print shake
client.send(our_handshake)
def interact(client, tick):
data = client.recv(255)
print 'got:%s' %(data)
client.send("clock ! tick%d\r" % (tick))
client.send("out ! recv\r")
if __name__ == '__main__':
start_server()
For those who haven't run through joe's example but still want to help, you just need to serve up interact.html through a web server and then start your server (The code assumes the webserver is running on localhost:8888)
For those who are interested this was the solution
import threading
import socket
def start_server():
tick = 0
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.bind(('localhost', 1234))
sock.listen(100)
while True:
print 'listening...'
csock, address = sock.accept()
tick+=1
print 'connection!'
handshake(csock, tick)
print 'handshaken'
while True:
interact(csock, tick)
tick+=1
def send_data(client, str_):
#_write(request, '\x00' + message.encode('utf-8') + '\xff')
str_ = '\x00' + str_.encode('utf-8') + '\xff'
return client.send(str_)
def recv_data(client, count):
data = client.recv(count)
return data.decode('utf-8', 'ignore')
def handshake(client, tick):
our_handshake = "HTTP/1.1 101 Web Socket Protocol Handshake\r\n"+"Upgrade: WebSocket\r\n"+"Connection: Upgrade\r\n"+"WebSocket-Origin: http://localhost:8888\r\n"+"WebSocket-Location: "+" ws://localhost:1234/websession\r\n\r\n"
shake = recv_data(client, 255)
print shake
#We want to send this without any encoding
client.send(our_handshake)
def interact(client, tick):
data = recv_data(client, 255)
print 'got:%s' %(data)
send_data(client, "clock ! tick%d" % (tick))
send_data(client, "out ! %s" %(data))
if __name__ == '__main__':
start_server()
Edit for liwp's request:
You can view a diff of the file here. Essentially my problem was the way I was decoding / encoding strings prior to sending / receiving. There's a websocket module being worked on for Apache on google code which I used to find out where I was going wrong.
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