172 lines
6.6 KiB
Python
172 lines
6.6 KiB
Python
"""
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rxws: WebSocket methods implemented for OpenWebRX
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This file is part of OpenWebRX,
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an open-source SDR receiver software with a web UI.
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Copyright (c) 2013-2015 by Andras Retzler <randras@sdr.hu>
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU Affero General Public License as
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published by the Free Software Foundation, either version 3 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Affero General Public License for more details.
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You should have received a copy of the GNU Affero General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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"""
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import base64
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import sha
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import select
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import code
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class WebSocketException(Exception):
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pass
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def handshake(myself):
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my_client_id=myself.path[4:]
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my_headers=myself.headers.items()
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my_header_keys=map(lambda x:x[0],my_headers)
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h_key_exists=lambda x:my_header_keys.count(x)
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h_value=lambda x:my_headers[my_header_keys.index(x)][1]
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#print "The Lambdas(tm)"
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#print h_key_exists("upgrade")
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#print h_value("upgrade")
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#print h_key_exists("sec-websocket-key")
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if (not h_key_exists("upgrade")) or not (h_value("upgrade")=="websocket") or (not h_key_exists("sec-websocket-key")):
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raise WebSocketException
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ws_key=h_value("sec-websocket-key")
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ws_key_toreturn=base64.b64encode(sha.new(ws_key+"258EAFA5-E914-47DA-95CA-C5AB0DC85B11").digest())
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#A sample list of keys we get: [('origin', 'http://localhost:8073'), ('upgrade', 'websocket'), ('sec-websocket-extensions', 'x-webkit-deflate-frame'), ('sec-websocket-version', '13'), ('host', 'localhost:8073'), ('sec-websocket-key', 't9J1rgy4fc9fg2Hshhnkmg=='), ('connection', 'Upgrade'), ('pragma', 'no-cache'), ('cache-control', 'no-cache')]
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myself.wfile.write("HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: "+ws_key_toreturn+"\r\nCQ-CQ-de: HA5KFU\r\n\r\n")
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def get_header(size):
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#this does something similar: https://github.com/lemmingzshadow/php-websocket/blob/master/server/lib/WebSocket/Connection.php
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ws_first_byte=0b10000010 # FIN=1, OP=2
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if(size>125):
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ws_second_byte=126 # The following two bytes will indicate frame size
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extended_size=chr((size>>8)&0xff)+chr(size&0xff) #Okay, it uses reverse byte order (little-endian) compared to anything else sent on TCP
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else:
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ws_second_byte=size
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#256 bytes binary message in a single unmasked frame | 0x82 0x7E 0x0100 [256 bytes of binary data]
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extended_size=""
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return chr(ws_first_byte)+chr(ws_second_byte)+extended_size
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def code_payload(data, masking_key=""):
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# both encode or decode
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if masking_key=="":
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key = (61, 84, 35, 6)
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else:
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key = [ord(i) for i in masking_key]
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encoded=""
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for i in range(0,len(data)):
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encoded+=chr(ord(data[i])^key[i%4])
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return encoded
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def xxdg(data):
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output=""
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for i in range(0,len(data)/8):
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output+=xxd(data[i:i+8])
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if i%2: output+="\n"
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else: output+=" "
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return output
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def xxd(data):
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#diagnostic purposes only
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output=""
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for d in data:
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output+=hex(ord(d))[2:].zfill(2)+" "
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return output
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#for R/W the WebSocket, use recv/send
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#for reading the TCP socket, use readsock
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#for writing the TCP socket, use myself.wfile.write and flush
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def readsock(myself,size,blocking):
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#http://thenestofheliopolis.blogspot.hu/2011/01/how-to-implement-non-blocking-two-way.html
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if blocking:
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return myself.rfile.read(size)
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else:
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poll = select.poll()
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poll.register(myself.rfile.fileno(), select.POLLIN or select.POLLPRI)
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fd = poll.poll(0) #timeout is 0
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if len(fd):
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f = fd[0]
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if f[1] > 0:
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return myself.rfile.read(size)
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return ""
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def recv(myself, blocking=False, debug=False):
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bufsize=70000
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#myself.connection.setblocking(blocking) #umm... we cannot do that with rfile
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if debug: print "ws_recv begin"
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try:
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data=readsock(myself,6,blocking)
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#print "rxws.recv bytes:",xxd(data)
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except:
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if debug: print "ws_recv error"
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return ""
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if debug: print "ws_recv recved"
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if(len(data)==0): return ""
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fin=ord(data[0])&128!=0
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is_text_frame=ord(data[0])&15==1
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length=ord(data[1])&0x7f
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data+=readsock(myself,length,blocking)
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#print "rxws.recv length is ",length," (multiple packets together?) len(data) =",len(data)
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has_one_byte_length=length<125
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masked=ord(data[1])&0x80!=0
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#print "len=", length, len(data)-2
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#print "fin, is_text_frame, has_one_byte_length, masked = ", (fin, is_text_frame, has_one_byte_length, masked)
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#print xxd(data)
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if fin and is_text_frame and has_one_byte_length:
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if masked:
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return code_payload(data[6:], data[2:6])
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else:
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return data[2:]
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#Useful links for ideas on WebSockets:
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# http://stackoverflow.com/questions/8125507/how-can-i-send-and-receive-websocket-messages-on-the-server-side
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# https://developer.mozilla.org/en-US/docs/WebSockets/Writing_WebSocket_server
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# http://tools.ietf.org/html/rfc6455#section-5.2
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def flush(myself):
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myself.wfile.flush()
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#or the socket, not the rfile:
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#lR,lW,lX = select.select([],[myself.connection,],[],60)
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def send(myself, data, begin_id="", debug=0):
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base_frame_size=35000 #could guess by MTU?
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debug=0
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#try:
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while True:
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counter=0
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from_end=len(data)-counter
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if from_end+len(begin_id)>base_frame_size:
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data_to_send=begin_id+data[counter:counter+base_frame_size-len(begin_id)]
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header=get_header(len(data_to_send))
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flush(myself)
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myself.wfile.write(header+data_to_send)
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flush(myself)
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if debug: print "rxws.send ==================== #1 if branch :: from={0} to={1} dlen={2} hlen={3}".format(counter,counter+base_frame_size-len(begin_id),len(data_to_send),len(header))
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else:
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data_to_send=begin_id+data[counter:]
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header=get_header(len(data_to_send))
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flush(myself)
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myself.wfile.write(header+data_to_send)
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flush(myself)
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if debug: print "rxws.send :: #2 else branch :: dlen={0} hlen={1}".format(len(data_to_send),len(header))
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#if debug: print "header:\n"+xxdg(header)+"\n\nws data:\n"+xxdg(data_to_send)
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break
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counter+=base_frame_size-len(begin_id)
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#except:
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# pass
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