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"""Routers that connect WebSockets to ZMQ sockets."""
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#-----------------------------------------------------------------------------
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# Copyright (C) 2011 The IPython Development Team
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#
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# Distributed under the terms of the BSD License. The full license is in
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# the file COPYING.txt, distributed as part of this software.
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#-----------------------------------------------------------------------------
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#-----------------------------------------------------------------------------
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# Imports
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#-----------------------------------------------------------------------------
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import uuid
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from Queue import Queue
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import json
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from IPython.config.configurable import Configurable
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from IPython.utils.traitlets import Instance, Int, Dict
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#-----------------------------------------------------------------------------
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# Classes
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#-----------------------------------------------------------------------------
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class ZMQStreamRouter(Configurable):
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zmq_stream = Instance('zmq.eventloop.zmqstream.ZMQStream')
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session = Instance('IPython.zmq.session.Session')
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max_msg_size = Int(2048, config=True, help="""
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The max raw message size accepted from the browser
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over a WebSocket connection.
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""")
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_clients = Dict()
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def __init__(self, **kwargs):
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super(ZMQStreamRouter,self).__init__(**kwargs)
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self.zmq_stream.on_recv(self._on_zmq_reply)
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def register_client(self, client):
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"""Register a client, returning a client uuid."""
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client_id = uuid.uuid4()
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self._clients[client_id] = client
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return client_id
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def unregister_client(self, client_id):
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"""Unregister a client by its client uuid."""
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del self._clients[client_id]
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def copy_clients(self, router):
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"""Copy the clients of another router to this one.
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This is used to enable the backend zeromq stream to disconnect
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and reconnect while the WebSocket connections to browsers
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remain, such as when a kernel is restarted.
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"""
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for client_id, client in router._clients.items():
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client.router = self
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self._clients[client_id] = client
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def forward_msg(self, client_id, msg):
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"""Forward a msg to a client by its id.
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The default implementation of this will fail silently if a message
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arrives on a socket that doesn't support it. This method should
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use max_msg_size to check and silently discard message that are too
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long."""
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pass
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def _on_zmq_reply(self, msg_list):
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"""Handle a message the ZMQ stream sends to the router.
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Usually, this is where the return message will be written to
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clients that need it using client.write_message().
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"""
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pass
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def _reserialize_reply(self, msg_list):
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"""Reserialize a reply message using JSON.
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This takes the msg list from the ZMQ socket, unserializes it using
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self.session and then serializes the result using JSON. This method
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should be used by self._on_zmq_reply to build messages that can
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be sent back to the browser.
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"""
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idents, msg_list = self.session.feed_identities(msg_list)
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msg = self.session.unserialize(msg_list)
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msg['header'].pop('date')
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return json.dumps(msg)
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class IOPubStreamRouter(ZMQStreamRouter):
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def _on_zmq_reply(self, msg_list):
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msg = self._reserialize_reply(msg_list)
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for client_id, client in self._clients.items():
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client.write_message(msg)
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class ShellStreamRouter(ZMQStreamRouter):
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_request_queue = Instance(Queue,(),{})
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def _on_zmq_reply(self, msg_list):
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msg = self._reserialize_reply(msg_list)
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client_id = self._request_queue.get(block=False)
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client = self._clients.get(client_id)
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if client is not None:
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client.write_message(msg)
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def forward_msg(self, client_id, msg):
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if len(msg) < self.max_msg_size:
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msg = json.loads(msg)
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to_send = self.session.serialize(msg)
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self._request_queue.put(client_id)
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self.session.send(self.zmq_stream, msg)
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