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"""Blocking channels
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Useful for test suites and blocking terminal interfaces.
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"""
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# Copyright (c) IPython Development Team.
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# Distributed under the terms of the Modified BSD License.
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try:
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from queue import Queue, Empty # Py 3
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except ImportError:
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from Queue import Queue, Empty # Py 2
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from IPython.utils.py3compat import string_types, iteritems
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# some utilities to validate message structure, these might get moved elsewhere
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# if they prove to have more generic utility
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def validate_string_dict(dct):
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"""Validate that the input is a dict with string keys and values.
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Raises ValueError if not."""
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for k,v in iteritems(dct):
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if not isinstance(k, string_types):
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raise ValueError('key %r in dict must be a string' % k)
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if not isinstance(v, string_types):
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raise ValueError('value %r in dict must be a string' % v)
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class ZMQSocketChannel(object):
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"""A ZMQ socket in a simple blocking API"""
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session = None
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socket = None
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stream = None
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_exiting = False
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proxy_methods = []
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def __init__(self, socket, session, loop=None):
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"""Create a channel.
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Parameters
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----------
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socket : :class:`zmq.Socket`
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The ZMQ socket to use.
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session : :class:`session.Session`
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The session to use.
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loop
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Unused here, for other implementations
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"""
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super(ZMQSocketChannel, self).__init__()
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self.socket = socket
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self.session = session
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def _recv(self, **kwargs):
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msg = self.socket.recv_multipart(**kwargs)
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ident,smsg = self.session.feed_identities(msg)
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return self.session.deserialize(smsg)
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def get_msg(self, block=True, timeout=None):
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""" Gets a message if there is one that is ready. """
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if block:
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if timeout is not None:
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timeout *= 1000 # seconds to ms
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ready = self.socket.poll(timeout)
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else:
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ready = self.socket.poll(timeout=0)
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if ready:
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return self._recv()
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else:
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raise Empty
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def get_msgs(self):
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""" Get all messages that are currently ready. """
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msgs = []
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while True:
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try:
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msgs.append(self.get_msg(block=False))
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except Empty:
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break
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return msgs
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def msg_ready(self):
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""" Is there a message that has been received? """
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return bool(self.socket.poll(timeout=0))
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def close(self):
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if self.socket is not None:
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try:
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self.socket.close(linger=0)
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except Exception:
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pass
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self.socket = None
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stop = close
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def is_alive(self):
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return (self.socket is not None)
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def _queue_send(self, msg):
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"""Pass a message to the ZMQ socket to send
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"""
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self.session.send(self.socket, msg)
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def start(self):
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pass
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