Sending / receiving WebSocket message over Python socket / WebSocket Client

Question

I wrote a simple WebSocket client. I used the code I found on SO, here: How can I send and receive WebSocket messages on the server side?.

I\'m using Python 2.7

Answer 1

I have hacked your code into something that at least sends a reply and receives an answer, by changing the encoding to use chr() to insert byte strings rather than decimals to the header. The decoding I have left alone but the other answer here has a solution for that.
The real guts of this is detailed here https://www.rfc-editor.org/rfc/rfc6455.txt
which details exactly what it is that you have to do

#!/usr/bin/env python
import socket
def encode_text_msg_websocket(data):
    bytesFormatted = []
    bytesFormatted.append(chr(129))
    bytesRaw = data.encode()
    bytesLength = len(bytesRaw)
    if bytesLength <= 125:
        bytesFormatted.append(chr(bytesLength))
    elif 126 <= bytesLength <= 65535:
        bytesFormatted.append(chr(126))
        bytesFormatted.append((chr(bytesLength >> 8)) & 255)
        bytesFormatted.append(chr(bytesLength) & 255)
    else:
        bytesFormatted.append(chr(127))
        bytesFormatted.append(chr((bytesLength >> 56)) & 255)
        bytesFormatted.append(chr((bytesLength >> 48)) & 255)
        bytesFormatted.append(chr((bytesLength >> 40)) & 255)
        bytesFormatted.append(chr((bytesLength >> 32)) & 255)
        bytesFormatted.append(chr((bytesLength >> 24)) & 255)
        bytesFormatted.append(chr((bytesLength >> 16)) & 255)
        bytesFormatted.append(chr((bytesLength >> 8)) & 255)
        bytesFormatted.append(chr(bytesLength) & 255)
    send_str = ""
    for i in bytesFormatted:
        send_str+=i
    send_str += bytesRaw
    return send_str

# connect 
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.settimeout(5.0)
try:
    sock.connect((socket.gethostbyname('ws.websocket.org'), 80))
except:
    print "Connection failed"
handshake = '\
GET /echo HTTP/1.1\r\n\
Host: echo.websocket.org\r\n\
Upgrade: websocket\r\n\
Connection: Upgrade\r\n\
Sec-WebSocket-Key: x3JJHMbDL1EzLkh9GBhXDw==\r\n\
Origin: http://example.com\r\n\
WebSocket-Protocol: echo\r\n\
Sec-WebSocket-Version: 13\r\n\r\n\
'
sock.send(bytes(handshake))
data = sock.recv(1024).decode('UTF-8')
print data

# send test msg
msg = encode_text_msg_websocket('Now is the winter of our discontent, made glorious Summer by this son of York')
print "Sent: ",repr(msg)
sock.sendall(bytes(msg))
# receive it back
response = sock.recv(1024)
#decode not sorted so ignore the first 2 bytes
print "\nReceived: ", response[2:].decode()
sock.close()

Result:

HTTP/1.1 101 Web Socket Protocol Handshake
Access-Control-Allow-Credentials: true
Access-Control-Allow-Headers: content-type
Access-Control-Allow-Headers: authorization
Access-Control-Allow-Headers: x-websocket-extensions
Access-Control-Allow-Headers: x-websocket-version
Access-Control-Allow-Headers: x-websocket-protocol
Access-Control-Allow-Origin: http://example.com
Connection: Upgrade
Date: Mon, 08 May 2017 15:08:33 GMT
Sec-WebSocket-Accept: HSmrc0sMlYUkAGmm5OPpG2HaGWk=
Server: Kaazing Gateway
Upgrade: websocket


Sent:  '\x81MNow is the winter of our discontent, made glorious Summer by this son of York'

Received:  Now is the winter of our discontent, made glorious Summer by this son of York

I should note here, that this is going to be a pig to code without pulling in some extra libraries, as @gushitong has done.