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"""Code common to Connection and Channel objects."""
# Copyright (C) 2007-2008 Barry Pederson <bp@barryp.org>)
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
from __future__ import absolute_import
from .exceptions import AMQPNotImplementedError, RecoverableConnectionError
from .serialization import AMQPWriter
try:
bytes
except NameError:
# Python 2.5 and lower
bytes = str
__all__ = ['AbstractChannel']
class AbstractChannel(object):
"""Superclass for both the Connection, which is treated
as channel 0, and other user-created Channel objects.
The subclasses must have a _METHOD_MAP class property, mapping
between AMQP method signatures and Python methods.
"""
def __init__(self, connection, channel_id):
self.connection = connection
self.channel_id = channel_id
connection.channels[channel_id] = self
self.method_queue = [] # Higher level queue for methods
self.auto_decode = False
def __enter__(self):
return self
def __exit__(self, *exc_info):
self.close()
def _send_method(self, method_sig, args=bytes(), content=None):
"""Send a method for our channel."""
conn = self.connection
if conn is None:
raise RecoverableConnectionError('connection already closed')
if isinstance(args, AMQPWriter):
args = args.getvalue()
conn.method_writer.write_method(
self.channel_id, method_sig, args, content,
)
def close(self):
"""Close this Channel or Connection"""
raise NotImplementedError('Must be overriden in subclass')
def wait(self, allowed_methods=None):
"""Wait for a method that matches our allowed_methods parameter (the
default value of None means match any method), and dispatch to it."""
method_sig, args, content = self.connection._wait_method(
self.channel_id, allowed_methods)
return self.dispatch_method(method_sig, args, content)
def dispatch_method(self, method_sig, args, content):
if content and \
self.auto_decode and \
hasattr(content, 'content_encoding'):
try:
content.body = content.body.decode(content.content_encoding)
except Exception:
pass
try:
amqp_method = self._METHOD_MAP[method_sig]
except KeyError:
raise AMQPNotImplementedError(
'Unknown AMQP method {0!r}'.format(method_sig))
if content is None:
return amqp_method(self, args)
else:
return amqp_method(self, args, content)
#: Placeholder, the concrete implementations will have to
#: supply their own versions of _METHOD_MAP
_METHOD_MAP = {}
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