AWSSQSReceiveMessageRequest Class Reference

Inherits from AWSRequest : AWSModel : AWSMTLModel
Declared in AWSSQSModel.h
AWSSQSModel.m

Overview

Required parameters: [QueueUrl]

  attributeNames

A list of attributes that need to be returned along with each message. These attributes include:

  • All - Returns all values.

  • ApproximateFirstReceiveTimestamp - Returns the time the message was first received from the queue (epoch time in milliseconds).

  • ApproximateReceiveCount - Returns the number of times a message has been received from the queue but not deleted.

  • SenderId

    • For an IAM user, returns the IAM user ID, for example ABCDEFGHI1JKLMNOPQ23R.

    • For an IAM role, returns the IAM role ID, for example ABCDE1F2GH3I4JK5LMNOP:i-a123b456.

  • SentTimestamp - Returns the time the message was sent to the queue (epoch time in milliseconds).

  • MessageDeduplicationId - Returns the value provided by the sender that calls the SendMessage action.

  • MessageGroupId - Returns the value provided by the sender that calls the SendMessage action. Messages with the same MessageGroupId are returned in sequence.

  • SequenceNumber - Returns the value provided by Amazon SQS.

Any other valid special request parameters (such as the following) that are specified are ignored:

  • ApproximateNumberOfMessages

  • ApproximateNumberOfMessagesDelayed

  • ApproximateNumberOfMessagesNotVisible

  • CreatedTimestamp

  • ContentBasedDeduplication

  • DelaySeconds

  • LastModifiedTimestamp

  • MaximumMessageSize

  • MessageRetentionPeriod

  • Policy

  • QueueArn,

  • ReceiveMessageWaitTimeSeconds

  • RedrivePolicy

  • FifoQueue

  • VisibilityTimeout

@property (nonatomic, strong) NSArray<NSString*> *attributeNames

Declared In

AWSSQSModel.h

  maxNumberOfMessages

The maximum number of messages to return. Amazon SQS never returns more messages than this value but might return fewer. Values can be from 1 to 10. Default is 1.

All of the messages are not necessarily returned.

@property (nonatomic, strong) NSNumber *maxNumberOfMessages

Declared In

AWSSQSModel.h

  messageAttributeNames

The name of the message attribute, where N is the index. The message attribute name can contain the following characters: A-Z, a-z, 0-9, underscore (_), hyphen (-), and period (.). The name must not start or end with a period, and it should not have successive periods. The name is case sensitive and must be unique among all attribute names for the message. The name can be up to 256 characters long. The name can't start with "AWS." or "Amazon." (or any variations in casing), because these prefixes are reserved for use by Amazon Web Services.

When using ReceiveMessage, you can send a list of attribute names to receive, or you can return all of the attributes by specifying "All" or ".*" in your request. You can also use "bar.*" to return all message attributes starting with the "bar" prefix.

@property (nonatomic, strong) NSArray<NSString*> *messageAttributeNames

Declared In

AWSSQSModel.h

  queueUrl

The URL of the Amazon SQS queue to take action on.

Queue URLs are case-sensitive.

@property (nonatomic, strong) NSString *queueUrl

Declared In

AWSSQSModel.h

  receiveRequestAttemptId

This parameter applies only to FIFO (first-in-first-out) queues.

The token used for deduplication of ReceiveMessage calls. If a networking issue occurs after a ReceiveMessage action, and instead of a response you receive a generic error, you can retry the same action with an identical ReceiveRequestAttemptId to retrieve the same set of messages, even if their visibility timeout has not yet expired.

  • You can use ReceiveRequestAttemptId only for 5 minutes after a ReceiveMessage action.

  • When you set FifoQueue, a caller of the ReceiveMessage action can provide a ReceiveRequestAttemptId explicitly.

  • If a caller of the ReceiveMessage action doesn't provide a ReceiveRequestAttemptId, Amazon SQS generates a ReceiveRequestAttemptId.

  • You can retry the ReceiveMessage action with the same ReceiveRequestAttemptId if none of the messages have been modified (deleted or had their visibility changes).

  • During a visibility timeout, subsequent calls with the same ReceiveRequestAttemptId return the same messages and receipt handles. If a retry occurs within the deduplication interval, it resets the visibility timeout. For more information, see Visibility Timeout in the Amazon Simple Queue Service Developer Guide.

    If a caller of the ReceiveMessage action is still processing messages when the visibility timeout expires and messages become visible, another worker reading from the same queue can receive the same messages and therefore process duplicates. Also, if a reader whose message processing time is longer than the visibility timeout tries to delete the processed messages, the action fails with an error.

    To mitigate this effect, ensure that your application observes a safe threshold before the visibility timeout expires and extend the visibility timeout as necessary.

  • While messages with a particular MessageGroupId are invisible, no more messages belonging to the same MessageGroupId are returned until the visibility timeout expires. You can still receive messages with another MessageGroupId as long as it is also visible.

  • If a caller of ReceiveMessage can't track the ReceiveRequestAttemptId, no retries will work until the original visibility timeout expires. As a result, delays might occur but the messages in the queue will remain in a strict order.

The length of ReceiveRequestAttemptId is 128 characters. ReceiveRequestAttemptId can contain alphanumeric characters (a-z, A-Z, 0-9) and punctuation (!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~).

For best practices of using ReceiveRequestAttemptId, see Using the ReceiveRequestAttemptId Request Parameter in the Amazon Simple Queue Service Developer Guide.

@property (nonatomic, strong) NSString *receiveRequestAttemptId

Declared In

AWSSQSModel.h

  visibilityTimeout

The duration (in seconds) that the received messages are hidden from subsequent retrieve requests after being retrieved by a ReceiveMessage request.

@property (nonatomic, strong) NSNumber *visibilityTimeout

Declared In

AWSSQSModel.h

  waitTimeSeconds

The duration (in seconds) for which the call will wait for a message to arrive in the queue before returning. If a message is available, the call will return sooner than WaitTimeSeconds.

@property (nonatomic, strong) NSNumber *waitTimeSeconds

Declared In

AWSSQSModel.h