1Mojo::RabbitMQ::Client:U:sCehranCnoenlt(r3ipbmu)ted PerlMoDjooc:u:mReanbtbaittiMoQn::Client::Channel(3pm)
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NAME

6       Mojo::RabbitMQ::Client::Channel - handles all channel related methods
7

SYNOPSIS

9         use Mojo::RabbitMQ::Client::Channel;
10
11         my $channel = Mojo::RabbitMQ::Client::Channel->new();
12
13         $channel->catch(sub { warn "Some channel error occurred: " . $_[1] });
14
15         $channel->on(
16           open => sub {
17             my ($channel) = @_;
18             ...
19           }
20         );
21         $channel->on(close => sub { warn "Channel closed" });
22
23         $client->open_channel($channel);
24

DESCRIPTION

26       Mojo::RabbitMQ::Client::Channel allows one to call all channel related
27       methods.
28

EVENTS

30       Mojo::RabbitMQ::Client::Channel inherits all events from
31       Mojo::EventEmitter and can emit the following new ones.
32
33   open
34         $channel->on(open => sub {
35           my ($channel) = @_;
36           ...
37         });
38
39       Emitted when channel receives Open-Ok.
40
41   close
42         $channel->on(close=> sub {
43           my ($channel, $frame) = @_;
44           ...
45         });
46
47       Emitted when channel gets closed, $frame contains close reason.
48

ATTRIBUTES

50       Mojo::RabbitMQ::Client::Channel has following attributes.
51
52   id
53         my $id = $channel->id;
54         $channel->id(20810);
55
56       If not set, Mojo::RabbitMQ::Client sets it to next free number when
57       channel is opened.
58
59   is_open
60         $channel->is_open ? "Channel is open" : "Channel is closed";
61
62   is_active
63         $channel->is_active ? "Channel is active" : "Channel is not active";
64
65       This can be modified on reception of Channel-Flow.
66
67   client
68         my $client = $channel->client;
69         $channel->client($client);
70

METHODS

72       Mojo::RabbitMQ::Client::Channel inherits all methods from
73       Mojo::EventEmitter and implements the following new ones.
74
75   close
76         $channel->close;
77
78       Cancels all consumers and closes channel afterwards.
79
80   declare_exchange
81         my $exchange = $channel->declare_exchange(
82           exchange => 'mojo',
83           type => 'fanout',
84           durable => 1,
85           ...
86         )->deliver;
87
88       Verify exchange exists, create if needed.
89
90       This method creates an exchange if it does not already exist, and if
91       the exchange exists, verifies that it is of the correct and expected
92       class.
93
94       Following arguments are accepted:
95
96       exchange
97         Unique exchange name
98
99       type
100         Each exchange belongs to one of a set of exchange types implemented
101         by the server. The exchange types define the functionality of the
102         exchange - i.e. how messages are routed through it. It is not valid
103         or meaningful to attempt to change the type of an existing exchange.
104
105       passive
106         If set, the server will reply with Declare-Ok if the exchange already
107         exists with the same name, and raise an error if not. The client can
108         use this to check whether an exchange exists without modifying the
109         server state. When set, all other method fields except name and no-
110         wait are ignored. A declare with both passive and no-wait has no
111         effect. Arguments are compared for semantic equivalence.
112
113       durable
114         If set when creating a new exchange, the exchange will be marked as
115         durable. Durable exchanges remain active when a server restarts. Non-
116         durable exchanges (transient exchanges) are purged if/when a server
117         restarts.
118
119       auto_delete
120         If set, the exchange is deleted when all queues have finished using
121         it.
122
123       internal
124         If set, the exchange may not be used directly by publishers, but only
125         when bound to other exchanges.  Internal exchanges are used to
126         construct wiring that is not visible to applications.
127
128   declare_exchange_p
129       Same as declare_exchange but auto-delivers method and returns a
130       Mojo::Promise object.
131
132         $channel->declare_exchange_p(
133           exchange => 'mojo',
134           type => 'fanout',
135           durable => 1,
136           ...
137         )->then(sub {
138           say "Exchange declared...";
139         })->catch(sub {
140           my $err = shift;
141           warn "Exchange declaration error: $err";
142         })->wait;
143
144   delete_exchange
145         $channel->delete_exchange(exchange => 'mojo')->deliver;
146
147       Delete an exchange.
148
149       This method deletes an exchange. When an exchange is deleted all queue
150       bindings on the exchange are cancelled.
151
152       Following arguments are accepted:
153
154       exchange
155         Exchange name.
156
157       if_unused
158         If set, the server will only delete the exchange if it has no queue
159         bindings. If the exchange has queue bindings the server does not
160         delete it but raises a channel exception instead.
161
162   delete_exchange_p
163       Same as delete_exchange but auto-delivers method and returns a
164       Mojo::Promise object.
165
166         $channel->delete_exchange_p(
167           exchange => 'mojo'
168         )->then(sub {
169           say "Exchange deleted...";
170         })->catch(sub {
171           my $err = shift;
172           warn "Exchange removal error: $err";
173         })->wait;
174
175   declare_queue
176         my $queue = $channel->declare_queue(queue => 'mq', durable => 1)->deliver
177
178       Declare queue, create if needed.
179
180       This method creates or checks a queue. When creating a new queue the
181       client can specify various properties that control the durability of
182       the queue and its contents, and the level of sharing for the queue.
183
184       Following arguments are accepted:
185
186       queue
187         The queue name MAY be empty, in which case the server MUST create a
188         new queue with a unique generated name and return this to the client
189         in the Declare-Ok method.
190
191       passive
192         If set, the server will reply with Declare-Ok if the queue already
193         exists with the same name, and raise an error if not. The client can
194         use this to check whether a queue exists without modifying the server
195         state. When set, all other method fields except name and no-wait are
196         ignored. A declare with both passive and no-wait has no effect.
197         Arguments are compared for semantic equivalence.
198
199       durable
200         If set when creating a new queue, the queue will be marked as
201         durable. Durable queues remain active when a server restarts. Non-
202         durable queues (transient queues) are purged if/when a server
203         restarts. Note that durable queues do not necessarily hold persistent
204         messages, although it does not make sense to send persistent messages
205         to a transient queue.
206
207       exclusive
208         Exclusive queues may only be accessed by the current connection, and
209         are deleted when that connection closes. Passive declaration of an
210         exclusive queue by other connections are not allowed.
211
212       auto_delete
213         If set, the queue is deleted when all consumers have finished using
214         it. The last consumer can be cancelled either explicitly or because
215         its channel is closed. If there was no consumer ever on the queue, it
216         won't be deleted. Applications can explicitly delete auto-delete
217         queues using the Delete method as normal.
218
219   declare_queue_p
220       Same as declare_queue but auto-delivers method and returns a
221       Mojo::Promise object.
222
223         $channel->declare_queue_p(
224           queue => 'mq',
225           durable => 1
226         )->then(sub {
227           say "Queue declared...";
228         })->catch(sub {
229           my $err = shift;
230           warn "Queue declaration error: $err";
231         })->wait;
232
233   bind_queue
234         $channel->bind_queue(
235           exchange => 'mojo',
236           queue => 'mq',
237           routing_key => ''
238         )->deliver;
239
240       Bind queue to an exchange.
241
242       This method binds a queue to an exchange. Until a queue is bound it
243       will not receive any messages. In a classic messaging model, store-and-
244       forward queues are bound to a direct exchange and subscription queues
245       are bound to a topic exchange.
246
247       Following arguments are accepted:
248
249       queue
250         Specifies the name of the queue to bind.
251
252       exchange
253         Name of the exchange to bind to.
254
255       routing_key
256         Specifies the routing key for the binding. The routing key is used
257         for routing messages depending on the exchange configuration. Not all
258         exchanges use a routing key - refer to the specific exchange
259         documentation. If the queue name is empty, the server uses the last
260         queue declared on the channel.  If the routing key is also empty, the
261         server uses this queue name for the routing key as well. If the queue
262         name is provided but the routing key is empty, the server does the
263         binding with that empty routing key. The meaning of empty routing
264         keys depends on the exchange implementation.
265
266   bind_queue_p
267       Same as bind_queue but auto-delivers method and returns a Mojo::Promise
268       object.
269
270         $channel->bind_queue_p(
271           exchange => 'mojo',
272           queue => 'mq',
273           routing_key => ''
274         )->then(sub {
275           say "Queue bound...";
276         })->catch(sub {
277           my $err = shift;
278           warn "Queue binding error: $err";
279         })->wait;
280
281   unbind_queue
282         $channel->unbind_queue(
283           exchange => 'mojo',
284           queue => 'mq',
285           routing_key => ''
286         )->deliver;
287
288       Unbind a queue from an exchange.
289
290       This method unbinds a queue from an exchange.
291
292       Following arguments are accepted:
293
294       queue
295         Specifies the name of the queue to unbind.
296
297       exchange
298         The name of the exchange to unbind from.
299
300       routing_key
301         Specifies the routing key of the binding to unbind.
302
303   unbind_queue_p
304       Same as unbind_queue but auto-delivers method and returns a
305       Mojo::Promise object.
306
307         $channel->unbind_queue_p(
308           exchange => 'mojo',
309           queue => 'mq',
310           routing_key => ''
311         )->then(sub {
312           say "Queue unbound...";
313         })->catch(sub {
314           my $err = shift;
315           warn "Queue unbinding error: $err";
316         })->wait;
317
318   purge_queue
319         $channel->purge_queue(queue => 'mq')->deliver;
320
321       Purge a queue.
322
323       This method removes all messages from a queue which are not awaiting
324       acknowledgment.
325
326       Following arguments are accepted:
327
328       queue
329         Specifies the name of the queue to purge.
330
331   purge_queue_p
332       Same as purge_queue but auto-delivers method and returns a
333       Mojo::Promise object.
334
335         $channel->purge_queue_p(
336           queue => 'mq',
337         )->then(sub {
338           say "Queue purged...";
339         })->catch(sub {
340           my $err = shift;
341           warn "Queue purging error: $err";
342         })->wait;
343
344   delete_queue
345         $channel->delete_queue(queue => 'mq', if_empty => 1)->deliver;
346
347       Delete a queue.
348
349       This method deletes a queue. When a queue is deleted any pending
350       messages are sent to a dead-letter queue if this is defined in the
351       server configuration, and all consumers on the queue are cancelled.
352
353       Following arguments are accepted:
354
355       queue
356         Specifies the name of the queue to delete.
357
358       if_unused
359         If set, the server will only delete the queue if it has no consumers.
360         If the queue has consumers the server does does not delete it but
361         raises a channel exception instead.
362
363       if_empty
364         If set, the server will only delete the queue if it has no messages.
365
366   delete_queue_p
367       Same as delete_queue but auto-delivers method and returns a
368       Mojo::Promise object.
369
370         $channel->delete_queue_p(
371           queue => 'mq',
372           if_empty => 1
373         )->then(sub {
374           say "Queue removed...";
375         })->catch(sub {
376           my $err = shift;
377           warn "Queue removal error: $err";
378         })->wait;
379
380   publish
381         my $message = $channel->publish(
382           exchange    => 'mojo',
383           routing_key => 'mq',
384           body        => 'simple text body',
385         );
386         $message->deliver();
387
388       Publish a message.
389
390       This method publishes a message to a specific exchange. The message
391       will be routed to queues as defined by the exchange configuration and
392       distributed to any active consumers when the transaction, if any, is
393       committed.
394
395       Following arguments are accepted:
396
397       exchange
398         Specifies the name of the exchange to publish to. The exchange name
399         can be empty, meaning the default exchange. If the exchange name is
400         specified, and that exchange does not exist, the server will raise a
401         channel exception.
402
403       routing_key
404         Specifies the routing key for the message. The routing key is used
405         for routing messages depending on the exchange configuration.
406
407       mandatory
408         This flag tells the server how to react if the message cannot be
409         routed to a queue.  If this flag is set, the server will return an
410         unroutable message with a Return method.  If this flag is zero, the
411         server silently drops the message.
412
413         All rejections are emitted as "reject" event.
414
415           $message->on(reject => sub {
416             my $message = shift;
417             my $frame = shift;
418             my $method_frame = $frame->method_frame;
419
420             my $reply_code = $method_frame->reply_code;
421             my $reply_text = $method_frame->reply_text;
422           });
423
424       immediate
425         This flag tells the server how to react if the message cannot be
426         routed to a queue consumer immediately. If this flag is set, the
427         server will return an undeliverable message with a Return method. If
428         this flag is zero, the server will queue the message, but with no
429         guarantee that it will ever be consumed.
430
431         As said above, all rejections are emitted as "reject" event.
432
433           $message->on(reject => sub { ... });
434
435   consume
436         my $consumer = $channel->consume(queue => 'mq');
437         $consumer->on(message => sub { ... });
438         $consumer->deliver;
439
440       This method asks the server to start a "consumer", which is a transient
441       request for messages from a specific queue. Consumers last as long as
442       the channel they were declared on, or until the client cancels them.
443
444       Following arguments are accepted:
445
446       queue
447         Specifies the name of the queue to consume from.
448
449       consumer_tag
450         Specifies the identifier for the consumer. The consumer tag is local
451         to a channel, so two clients can use the same consumer tags. If this
452         field is empty the server will generate a unique tag.
453
454           $consumer->on(success => sub {
455             my $consumer = shift;
456             my $frame = shift;
457
458             my $consumer_tag = $frame->method_frame->consumer_tag;
459           });
460
461       no_local (not implemented in RabbitMQ!)
462         If the no-local field is set the server will not send messages to the
463         connection that published them.
464
465         See RabbitMQ Compatibility and Conformance
466         <https://www.rabbitmq.com/specification.html>
467
468       no_ack
469         If this field is set the server does not expect acknowledgements for
470         messages. That is, when a message is delivered to the client the
471         server assumes the delivery will succeed and immediately dequeues it.
472         This functionality may increase performance but at the cost of
473         reliability. Messages can get lost if a client dies before they are
474         delivered to the application.
475
476       exclusive
477         Request exclusive consumer access, meaning only this consumer can
478         access the queue.
479
480   cancel
481         $channel->cancel(consumer_tag => 'amq.ctag....')->deliver;
482
483       End a queue consumer.
484
485       This method cancels a consumer. This does not affect already delivered
486       messages, but it does mean the server will not send any more messages
487       for that consumer. The client may receive an arbitrary number of
488       messages in between sending the cancel method and receiving the cancel-
489       ok reply.
490
491       Following arguments are accepted:
492
493       consumer_tag
494         Holds the consumer tag specified by the client or provided by the
495         server.
496
497   get
498         my $get = $channel->get(queue => 'mq')
499         $get->deliver;
500
501       Direct access to a queue.
502
503       This method provides a direct access to the messages in a queue using a
504       synchronous dialogue that is designed for specific types of application
505       where synchronous functionality is more important than performance.
506
507       This is simple event emitter to which you have to subscribe. It can
508       emit:
509
510       message
511         Provide client with a message.
512
513         This method delivers a message to the client following a get method.
514         A message delivered by 'get-ok' must be acknowledged unless the no-
515         ack option was set in the get method.
516
517         You can access all get-ok reply parameters as below:
518
519           $get->on(message => sub {
520             my $get = shift;
521             my $get_ok = shift;
522             my $message = shift;
523
524             say "Still got: " . $get_ok->method_frame->message_count;
525           });
526
527       empty
528         Indicate no messages available.
529
530         This method tells the client that the queue has no messages available
531         for the client.
532
533       Following arguments are accepted:
534
535       queue
536         Specifies the name of the queue to get a message from.
537
538       no_ack
539         If this field is set the server does not expect acknowledgements for
540         messages. That is, when a message is delivered to the client the
541         server assumes the delivery will succeed and immediately dequeues it.
542         This functionality may increase performance but at the cost of
543         reliability. Messages can get lost if a client dies before they are
544         delivered to the application.
545
546   ack
547         $channel->ack(delivery_tag => 1);
548
549       Acknowledge one or more messages.
550
551       When sent by the client, this method acknowledges one or more messages
552       delivered via the Deliver or Get-Ok methods. When sent by server, this
553       method acknowledges one or more messages published with the Publish
554       method on a channel in confirm mode. The acknowledgement can be for a
555       single message or a set of messages up to and including a specific
556       message.
557
558       Following arguments are accepted:
559
560       delivery_tag
561         Server assigned delivery tag that was received with a message.
562
563       multiple
564         If set to 1, the delivery tag is treated as "up to and including", so
565         that multiple messages can be acknowledged with a single method. If
566         set to zero, the delivery tag refers to a single message. If the
567         multiple field is 1, and the delivery tag is zero, this indicates
568         acknowledgement of all outstanding messages.
569
570   qos
571         $channel->qos(prefetch_count => 1)->deliver;
572
573       Sets specified Quality of Service to channel, or entire connection.
574       Accepts following arguments:
575
576       prefetch_size
577         Prefetch window size in octets.
578
579       prefetch_count
580         Prefetch window in complete messages.
581
582       global
583         If set all settings will be applied connection wide.
584
585   recover
586         $channel->recover(requeue => 0)->deliver;
587
588       Redeliver unacknowledged messages.
589
590       This method asks the server to redeliver all unacknowledged messages on
591       a specified channel. Zero or more messages may be redelivered.
592
593       requeue
594         If this field is zero, the message will be redelivered to the
595         original recipient. If this bit is 1, the server will attempt to
596         requeue the message, potentially then delivering it to an alternative
597         subscriber.
598
599   reject
600         $channel->reject(delivery_tag => 1, requeue => 0)->deliver;
601
602       Reject an incoming message.
603
604       This method allows a client to reject a message. It can be used to
605       interrupt and cancel large incoming messages, or return untreatable
606       messages to their original queue.
607
608       Following arguments are accepted:
609
610       delivery_tag
611         Server assigned delivery tag that was received with a message.
612
613       requeue
614         If requeue is true, the server will attempt to requeue the message.
615         If requeue is false or the requeue attempt fails the messages are
616         discarded or dead-lettered.
617
618   select_tx
619       Work with transactions.
620
621       The Tx class allows publish and ack operations to be batched into
622       atomic units of work.  The intention is that all publish and ack
623       requests issued within a transaction will complete successfully or none
624       of them will. Servers SHOULD implement atomic transactions at least
625       where all publish or ack requests affect a single queue. Transactions
626       that cover multiple queues may be non-atomic, given that queues can be
627       created and destroyed asynchronously, and such events do not form part
628       of any transaction.  Further, the behaviour of transactions with
629       respect to the immediate and mandatory flags on Basic.Publish methods
630       is not defined.
631
632         $channel->select_tx()->deliver;
633
634       Select standard transaction mode.
635
636       This method sets the channel to use standard transactions. The client
637       must use this method at least once on a channel before using the Commit
638       or Rollback methods.
639
640   commit_tx
641         $channel->commit_tx()->deliver;
642
643       Commit the current transaction.
644
645       This method commits all message publications and acknowledgments
646       performed in the current transaction. A new transaction starts
647       immediately after a commit.
648
649   rollback_tx
650         $channel->rollback_tx()->deliver;
651
652       Abandon the current transaction.
653
654       This method abandons all message publications and acknowledgments
655       performed in the current transaction. A new transaction starts
656       immediately after a rollback. Note that unacked messages will not be
657       automatically redelivered by rollback; if that is required an explicit
658       recover call should be issued.
659

SEE ALSO

661       Mojo::RabbitMQ::Client, Mojo::RabbitMQ::Client::Method,
662       Net::AMQP::Protocol::v0_8
663
665       Copyright (C) 2015-2017, Sebastian Podjasek and others
666
667       Based on AnyEvent::RabbitMQ - Copyright (C) 2010 Masahito Ikuta,
668       maintained by "bobtfish@bobtfish.net"
669
670       This program is free software, you can redistribute it and/or modify it
671       under the terms of the Artistic License version 2.0.
672
673
674
675perl v5.30.1                      2020-01-3M0ojo::RabbitMQ::Client::Channel(3pm)
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