Impossible to reopen closed channel

[Jurdanas Kriauciunas]

Hi,

AMQClient.channels dict stores all opened channels. But if error occurs channel is closed, AMQChannel.closed variable updated but AMQPClient.channels dict is not updated.
I have done a small patch: AMQClient.channel() function checks not only if channel exists but also checks 'closed' variable. And recreates channel if needed.

[Vsevolod Novikov (nnseva)]

It is possible and useful to remove the channel from the client dict immediately when the channel is closed, using appropriate event. The applied patch does it such a way, that the code like the following works correctly:

    try:
        yield self.chan.queue_delete(queue="chatrooms") # here the 404 happens
    except Exception,ex:
        print "Error deleting queue %s, ignored" % ex
        self.chan = yield self.conn.channel(1) # here the channel is recreated just because it is already removed from the dict
        yield self.chan.channel_open()