94 lines
3.3 KiB
Python
94 lines
3.3 KiB
Python
"""Code common to Connection and Channel objects."""
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# Copyright (C) 2007-2008 Barry Pederson <bp@barryp.org>)
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#
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# This library is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 2.1 of the License, or (at your option) any later version.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with this library; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
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from __future__ import absolute_import
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from .exceptions import AMQPNotImplementedError, RecoverableConnectionError
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from .serialization import AMQPWriter
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__all__ = ['AbstractChannel']
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class AbstractChannel(object):
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"""Superclass for both the Connection, which is treated
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as channel 0, and other user-created Channel objects.
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The subclasses must have a _METHOD_MAP class property, mapping
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between AMQP method signatures and Python methods.
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"""
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def __init__(self, connection, channel_id):
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self.connection = connection
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self.channel_id = channel_id
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connection.channels[channel_id] = self
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self.method_queue = [] # Higher level queue for methods
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self.auto_decode = False
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def __enter__(self):
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return self
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def __exit__(self, *exc_info):
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self.close()
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def _send_method(self, method_sig, args=bytes(), content=None):
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"""Send a method for our channel."""
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conn = self.connection
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if conn is None:
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raise RecoverableConnectionError('connection already closed')
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if isinstance(args, AMQPWriter):
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args = args.getvalue()
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conn.method_writer.write_method(
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self.channel_id, method_sig, args, content,
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)
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def close(self):
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"""Close this Channel or Connection"""
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raise NotImplementedError('Must be overriden in subclass')
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def wait(self, allowed_methods=None):
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"""Wait for a method that matches our allowed_methods parameter (the
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default value of None means match any method), and dispatch to it."""
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method_sig, args, content = self.connection._wait_method(
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self.channel_id, allowed_methods)
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return self.dispatch_method(method_sig, args, content)
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def dispatch_method(self, method_sig, args, content):
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if content and \
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self.auto_decode and \
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hasattr(content, 'content_encoding'):
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try:
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content.body = content.body.decode(content.content_encoding)
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except Exception:
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pass
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try:
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amqp_method = self._METHOD_MAP[method_sig]
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except KeyError:
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raise AMQPNotImplementedError(
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'Unknown AMQP method {0!r}'.format(method_sig))
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if content is None:
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return amqp_method(self, args)
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else:
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return amqp_method(self, args, content)
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#: Placeholder, the concrete implementations will have to
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#: supply their own versions of _METHOD_MAP
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_METHOD_MAP = {}
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