class WebSocketClient(BaseComponent):
"""
An RFC 6455 compliant WebSocket client component. Upon receiving a
:class:`circuits.web.client.Connect` event, the component tries to
establish the connection to the server in a two stage process. First, a
:class:`circuits.net.events.connect` event is sent to a child
:class:`~.sockets.TCPClient`. When the TCP connection has been established,
the HTTP request for opening the WebSocket is sent to the server.
A failure in this setup process is signaled by raising an
:class:`~.client.NotConnected` exception.
When the server accepts the request, the WebSocket connection is
established and can be used very much like an ordinary socket
by handling :class:`~.net.events.read` events on and sending
:class:`~.net.events.write` events to the channel
specified as the ``wschannel`` parameter of the constructor. Firing
a :class:`~.net.events.close` event on that channel closes the
connection in an orderly fashion (i.e. as specified by the
WebSocket protocol).
"""
channel = "wsclient"
def __init__(self, url, channel=channel, wschannel="ws", headers=None):
"""
:param url: the URL to connect to.
:param channel: the channel used by this component
:param wschannel: the channel used for the actual WebSocket
communication (read, write, close events)
:param headers: additional headers to be passed with the
WebSocket setup HTTP request
"""
super(WebSocketClient, self).__init__(channel=channel)
self._url = url
self._headers = headers or {}
self._response = None
self._pending = 0
self._wschannel = wschannel
self._transport = TCPClient(channel=self.channel).register(self)
HTTP(channel=self.channel).register(self._transport)
@handler("ready")
def _on_ready(self, event, *args, **kwargs):
p = urlparse(self._url)
if not p.hostname:
raise ValueError("URL must be absolute")
self._host = p.hostname
if p.scheme == "ws":
self._secure = False
self._port = p.port or 80
elif p.scheme == "wss":
self._secure = True
self._port = p.port or 443
else:
raise NotConnected()
self._resource = p.path or "/"
if p.query:
self._resource += "?" + p.query
self.fire(connect(self._host, self._port, self._secure),
self._transport)
@handler("connected")
def _on_connected(self, host, port):
headers = Headers([(k, v) for k, v in self._headers.items()])
# Clients MUST include Host header in HTTP/1.1 requests (RFC 2616)
if not "Host" in headers:
headers["Host"] = self._host \
+ (":" + str(self._port)) if self._port else ""
headers["Upgrade"] = "websocket"
headers["Connection"] = "Upgrade"
try:
sec_key = os.urandom(16)
except NotImplementedError:
sec_key = "".join([chr(random.randint(0, 255)) for i in range(16)])
headers["Sec-WebSocket-Key"] = base64.b64encode(sec_key).decode("latin1")
headers["Sec-WebSocket-Version"] = "13"
command = "GET %s HTTP/1.1" % self._resource
message = "%s\r\n%s" % (command, headers)
self._pending += 1
self.fire(write(message.encode('utf-8')), self._transport)
return True
@handler("response")
def _on_response(self, response):
self._response = response
self._pending -= 1
if response.headers.get("Connection") == "Close" \
or response.status != 101:
self.fire(close(), self._transport)
raise NotConnected()
WebSocketCodec(data=response.body.read(), channel=self._wschannel).register(self)
@handler("error", priority=10)
def _on_error(self, event, error, *args, **kwargs):
# For HTTP 1.1 we leave the connection open. If the peer closes
# it after some time and we have no pending request, that's OK.
if isinstance(error, SocketError) and error.args[0] == ECONNRESET \
and self._pending == 0:
event.stop()
def close(self):
if self._transport is not None:
self._transport.close()
@property
def connected(self):
return getattr(self._transport, "connected", False) \
if hasattr(self, "_transport") else False
class WebSocketClient(BaseComponent):
"""
An RFC 6455 compliant WebSocket client component. Upon receiving a
:class:`circuits.web.client.Connect` event, the component tries to
establish the connection to the server in a two stage process. First, a
:class:`circuits.net.events.connect` event is sent to a child
:class:`~.sockets.TCPClient`. When the TCP connection has been established,
the HTTP request for opening the WebSocket is sent to the server.
A failure in this setup process is signaled by raising an
:class:`~.client.NotConnected` exception.
When the server accepts the request, the WebSocket connection is
established and can be used very much like an ordinary socket
by handling :class:`~.net.events.read` events on and sending
:class:`~.net.events.write` events to the channel
specified as the ``wschannel`` parameter of the constructor. Firing
a :class:`~.net.events.close` event on that channel closes the
connection in an orderly fashion (i.e. as specified by the
WebSocket protocol).
"""
channel = "wsclient"
def __init__(self, url, channel=channel, wschannel="ws", headers=None):
"""
:param url: the URL to connect to.
:param channel: the channel used by this component
:param wschannel: the channel used for the actual WebSocket
communication (read, write, close events)
:param headers: additional headers to be passed with the
WebSocket setup HTTP request
"""
super(WebSocketClient, self).__init__(channel=channel)
self._url = url
self._headers = headers or {}
self._response = None
self._pending = 0
self._wschannel = wschannel
self._codec = None
self._transport = TCPClient(channel=self.channel).register(self)
HTTP(channel=self.channel).register(self._transport)
@handler("ready")
def _on_ready(self, event, *args, **kwargs):
p = urlparse(self._url)
if not p.hostname:
raise ValueError("URL must be absolute")
self._host = p.hostname
if p.scheme == "ws":
self._secure = False
self._port = p.port or 80
elif p.scheme == "wss":
self._secure = True
self._port = p.port or 443
else:
raise NotConnected()
self._resource = p.path or "/"
if p.query:
self._resource += "?" + p.query
self.fire(connect(self._host, self._port, self._secure),
self._transport)
@handler("connected")
def _on_connected(self, host, port):
headers = Headers([(k, v) for k, v in self._headers.items()])
# Clients MUST include Host header in HTTP/1.1 requests (RFC 2616)
if "Host" not in headers:
headers["Host"] = self._host \
+ (":" + str(self._port)) if self._port else ""
headers["Upgrade"] = "websocket"
headers["Connection"] = "Upgrade"
try:
sec_key = os.urandom(16)
except NotImplementedError:
sec_key = "".join([chr(random.randint(0, 255)) for i in range(16)])
headers["Sec-WebSocket-Key"] = base64.b64encode(sec_key).decode(
"latin1")
headers["Sec-WebSocket-Version"] = "13"
UNSAFE_CHARS = re.compile(
'[^0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~]'
)
escaped_resource = UNSAFE_CHARS.sub(
'',
self._resource.encode('ASCII', 'replace').decode('ASCII'))
command = "GET %s HTTP/1.1" % (escaped_resource, )
message = "%s\r\n%s" % (command, headers)
self._pending += 1
self.fire(write(message.encode('utf-8')), self._transport)
return True
@handler("response")
def _on_response(self, response):
self._response = response
self._pending -= 1
if response.headers.get("Connection", "").lower() == "close" \
or response.status != 101:
self.fire(close(), self._transport)
raise NotConnected()
self._codec = WebSocketCodec(data=response.body.read(),
channel=self._wschannel).register(self)
@handler('read')
def _on_read(self, event, *args):
# FIXME: every read-event is lost due to a race condition between
# WebSocketCodec().register() and the registered()-event of that instance.
if len(args) != 1:
return
if self._codec is not None and self._codec.parent is self:
if 'read' not in self._codec.events():
event.stop()
self.fire(event.create('read', *args))
else:
self.removeHandler(self._on_read)
@handler("error", priority=10)
def _on_error(self, event, error, *args, **kwargs):
# For HTTP 1.1 we leave the connection open. If the peer closes
# it after some time and we have no pending request, that's OK.
if isinstance(error, SocketError) and error.args[0] == ECONNRESET \
and self._pending == 0:
event.stop()
def close(self):
if self._transport is not None:
self._transport.close()
@property
def connected(self):
return getattr(self._transport, "connected", False) \
if hasattr(self, "_transport") else False
