WebSocket protocol for Diesel

README.md

WebSocket protocol for Diesel

Not tested, but a potential echo + timeout example:

from diesel import Application, Service, until_eol, sleep, bytes
from websocket import WebSocket
import time

def skip_one():
    yield bytes(1)
    yield up(until_eol())

def hi_server():
    while True:
        inp, to = yield (skip_one, sleep(3))
        if to:
            yield '%s timeout!\n' % time.asctime()
        else:
            yield 'you said %s' % inp

app = Application()
app.add_service(Service(WebSocket(hi_server), 8000))
app.run()

websocket.py

'''
Websocket for Diesel.
'''

from diesel import until

BEGINFRAME, ENDFRAME = '\x00', '\xff'
HANDSHAKE = '''\
HTTP/1.1 101 Web Socket Protocol Handshake\r\n\
Upgrade: WebSocket\r\n\
Connection: Upgrade\r\n'''

class WebSocketError(Exception): pass

class Request(object):
    '''WebSocket request.
    '''
    def __init__(self, method, path, version):
        self.method, self.path, self.version = method, path, version

    def parse_headers(self, headers):
        self.headers = dict([
            line.split(': ')
            for line in headers.split('\r\n')
            ])

class WebSocket(object):
    '''WebSocket service.
    '''

    def __init__(self, app):
        self.app = app()

    def __call__(self, addr):
        '''WebSocket handler.
        '''
        yield HANDSHAKE

        request_line = yield until('\r\n')
        headers = yield until('\r\n\r\n')
        req = Request(*request_line.strip().split(' '))
        req.parse_headers(headers.strip())

        origin = 'WebSocket-Origin: %s' % req.headers['Origin']
        loc = 'WebSocket-Location: ws://%s' % req.headers['Host'] + req.path
        yield '%s\r\n%s\r\n\r\n' % (origin, loc)

        while True:
            start, out = yield (bytes(1), self.app.next())
            if start:
                if not start == BEGINFRAME:
                    raise WebSocketError()
                incoming = yield (until(ENDFRAME))
                self.app.send(incoming)
            else:
                yield out