Acknowledges one or more messages. If multiple is set to true, all messages up to the one specified by delivery_tag are considered acknowledged by the server.

End a queue consumer.

This method cancels a consumer. This does not affect already delivered messages, but it does mean the server will not send any more messages for that consumer. The client may receive an arbitrary number of messages in between sending the cancel method and receiving the reply.

Removes the return handler, if it exists. Does nothing if there is no such handler.

Registers a queue consumer process. The pid of the process can be set using the consumer_pid argument and defaults to the calling process.

The consumer process will receive the following data structures:

• {:basic_deliver, payload, meta} - This is sent for each message consumed, where payload contains the message content and meta contains all the metadata set when sending with Basic.publish or additional info set by the broker;
• {:basic_consume_ok, %{consumer_tag: consumer_tag}} - Sent when the consumer process is registered with Basic.consume. The caller receives the same information as the return of Basic.consume;
• {:basic_cancel, %{consumer_tag: consumer_tag, no_wait: no_wait}} - Sent by the broker when the consumer is unexpectedly cancelled (such as after a queue deletion)
• {:basic_cancel_ok, %{consumer_tag: consumer_tag}} - Sent to the consumer process after a call to Basic.cancel

Polls a queue for an existing message.

Returns the tuple {:empty, meta} if the queue is empty or the tuple {:ok, payload, meta} if at least one message exists in the queue. The returned meta map includes the entry message_count with the current number of messages in the queue.

Receiving messages by polling a queue is not as as efficient as subscribing a consumer to a queue, so consideration should be taken when receiving large volumes of messages.

Setting the no_ack option to true will tell the broker that the receiver will not send an acknowledgement of the message. Once it believes it has delivered a message, then it is free to assume that the consuming application has taken responsibility for it. In general, a lot of applications will not want these semantics, rather, they will want to explicitly acknowledge the receipt of a message and have no_ack with the default value of false.

Negative acknowledge of one or more messages. If multiple is set to true, all messages up to the one specified by delivery_tag are considered as not acknowledged by the server. If requeue is set to true, the message will be returned to the queue and redelivered to the next available consumer.

This is a RabbitMQ specific extension to AMQP 0.9.1. It is equivalent to reject, but allows rejecting multiple messages using the multiple option.

Publishes a message to an Exchange.

This method publishes a message to a specific exchange. The message will be routed to queues as defined by the exchange configuration and distributed to any subscribers.

The parameter exchange specifies the name of the exchange to publish to. If set to empty string, it publishes to the default exchange. The routing_key parameter specifies the routing key for the message.

The payload parameter specifies the message content as a binary.

In addition to the previous parameters, the following options can be used:

Options

• :mandatory - If set, returns an error if the broker can’t route the message to a queue (default false);
• :immediate - If set, returns an error if the broker can’t deliver te message to a consumer immediately (default false);
• :content_type - MIME Content type;
• :content_encoding - MIME Content encoding;
• :headers - Message headers. Can be used with headers Exchanges;
• :persistent - If set, uses persistent delivery mode. Messages marked as persistent that are delivered to durable queues will be logged to disk;
• :correlation_id - application correlation identifier;
• :priority - message priority, ranging from 0 to 9;
• :reply_to - name of the reply queue;
• :expiration - how long the message is valid (in milliseconds);
• :message_id - message identifier;
• :timestamp - timestamp associated with this message (epoch time);
• :type - message type as a string;
• :user_id - creating user ID. RabbitMQ will validate this against the active connection user;
• :app_id - publishing application ID.

Examples

iex> AMQP.Basic.publish chan, "my_exchange", "my_routing_key", "Hello World!", persistent: true
:ok

Sets the message prefetch count or prefetech size (in bytes). If global is set to true this applies to the entire Connection, otherwise it applies only to the specified Channel.

Asks the server to redeliver all unacknowledged messages on a specified channel.

If requeue is set to true the server will attempt to requeue the message, potentially delivering it to another subscriber. Otherwise it will be redelivered to the original recipient.

Rejects (and, optionally, requeues) a message.

Registers a handler to deal with returned messages. The registered process will receive {:basic_return, payload, meta} data structures.