To give you an idea of what I am trying to accomplish with Twisted Web and Autobahn websockets: my UI currently sends an initial HTTP GET request with an upgrade to a websocket in the header. Upon reading that in Twisted Web, the connection needs to switch from HTTP to a websocket protocol to pass data back and forth. Note that this websocket upgrade happens on the same port, port 8000.
Does anyone know how I can implement what I am trying to do? Thank you so much.
EDIT: updated code for working example. You can find it here: Payload from POST Request is Cutoff (Twisted Web)
Here is my code using Twisted Web:
class HttpResource(resource.Resource):
isLeaf = 1
def __init__(self):
self.children = {}
self.ws_port = None
print 'resource invoked'
def render_GET(self, request):
print 'render invoked'
if request.getHeader('Sec-WebSocket-Key'):
# Processing the Key as per RFC 6455
key = request.getHeader('Sec-WebSocket-Key')
h = hashlib.sha1(key + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11")
request.setHeader('Sec-WebSocket-Accept', base64.b64encode(h.digest()))
# setting response headers
request.setHeader('Upgrade', 'websocket')
request.setHeader('Connection', 'Upgrade')
request.setResponseCode(101)
return ''
else:
log("Regular HTTP GET request.")
return "<html><body style='margin: 0; overflow: hidden;'><iframe style='width: 100%; height: 100%; border: none;' src='http://tsa-graphiql.herokuapp.com/'></iframe></body></html>"
def render_POST(self,request):
log("POST request")
request.setResponseCode(200)
def handle_single_query(self, queryData):
log("Handle single query data.")
return
class HttpWsChannel(http.HTTPChannel):
def dataReceived(self, data):
log('Data received:\n{}'.format(data))
if data.startswith('GET'):
# This will invoke the render method of resource provided
http.HTTPChannel.dataReceived(self, data)
if data.startswith('POST'):
http.HTTPChannel.dataReceived(self, data)
else:
"""
Pass binary data to websocket class.
"""
ws_protocol = self.site.ws_factory.protocol(self.site.ws_factory.connection_subscriptions)
log(ws_protocol)
#just echo for now
# self.transport.write(data)
class HttpFactory(Site):
"""
Factory which takes care of tracking which protocol
instances or request instances are responsible for which
named response channels, so incoming messages can be
routed appropriately.
"""
def __init__(self, resource):
http.HTTPFactory.__init__(self)
self.resource = resource
self.ws_factory = WsProtocolFactory("ws://127.0.0.1:8000")
self.ws_factory.protocol = WsProtocol
def buildProtocol(self, addr):
try:
channel = HttpWsChannel()
channel.requestFactory = self.requestFactory
channel.site = self
return channel
except Exception as e:
log("Could not build protocol: {}".format(e))
site = HttpFactory(HttpResource())
if __name__ == '__main__':
reactor.listenTCP(8000, site)
reactor.run()
EDIT 7/8/2017: Here is the new code I am trying below. The websocket messages are received successfully via the onMessage method. However the HTTP requests are not working. The current error I am getting on a GET request is:
<html>
<head><title>404 - No Such Resource</title></head>
<body>
<h1>No Such Resource</h1>
<p>No such child resource.</p>
</body>
</html>
Python code
from twisted.web.server import (
Site,
)
from twisted.internet import reactor
from twisted.web.resource import (
Resource,
)
from autobahn.twisted.websocket import (
WebSocketServerProtocol,
WebSocketServerFactory,
)
from autobahn.twisted.resource import (
WebSocketResource,
)
class WebSocketProtocol(WebSocketServerProtocol):
def onConnect(self, request):
print("WebSocket connection request: {}".format(request))
def onMessage(self, payload, isBinary):
print("onMessage: {}".format(payload))
if __name__ == '__main__':
factory = WebSocketServerFactory()
factory.protocol = WebSocketProtocol
resource = WebSocketResource(factory)
root = Resource()
root.putChild(b"ws", resource)
site = Site(root)
reactor.listenTCP(8000, site)
reactor.run()
So after reading a little bit on Google, I found this website that explains how to upgrade the HTTP connection to a websocket connection via Autobahn Twisted: Read and Set request headers via Autobahn Twisted.
The code that I was able to get to work is shown below!
from twisted.web.server import (
Site,
)
from twisted.internet import reactor
from twisted.web.resource import (
Resource,
)
from autobahn.twisted.websocket import (
WebSocketServerProtocol,
WebSocketServerFactory,
)
from autobahn.twisted.resource import (
WebSocketResource,
)
class HttpResource(Resource):
isLeaf = True
def render_GET(self, request):
return "<html><body style='margin: 0; overflow: hidden;'><iframe style='width: 100%; height: 100%; border: none;' src='http://tsa-graphiql.herokuapp.com/'></iframe></body></html>"
class WebSocketProtocol(WebSocketServerProtocol):
def onConnect(self, request):
custom_header = {}
if request.headers['sec-websocket-key']:
custom_header['sec-websocket-protocol'] = 'graphql-ws'
return (None, custom_header)
def onMessage(self, payload, isBinary):
print("onMessage: {}".format(payload))
if __name__ == '__main__':
factory = WebSocketServerFactory()
factory.protocol = WebSocketProtocol
resource = WebSocketResource(factory)
root = Resource()
root.putChild("", HttpResource())
root.putChild(b"ws", ws_resource)
site = Site(root)
reactor.listenTCP(8000, site)