AWSSQSReceiveMessageRequest Class Reference
|Inherits from||AWSRequest : AWSModel : AWSMTLModel|
A list of s 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.
For an IAM user, returns the IAM user ID, for example
For an IAM role, returns the IAM role ID, for example
SentTimestamp- Returns the time the message was sent to the queue (epoch time in milliseconds).
MessageDeduplicationId- Returns the value provided by the producer that calls the
MessageGroupId- Returns the value provided by the producer that calls the
SendMessageaction. Messages with the same
MessageGroupIdare returned in sequence.
SequenceNumber- Returns the value provided by Amazon SQS.
@property (nonatomic, strong) NSArray<NSString*> *attributeNames
The maximum number of messages to return. Amazon SQS never returns more messages than this value (however, fewer messages might be returned). Valid values: 1 to 10. Default: 1.
@property (nonatomic, strong) NSNumber *maxNumberOfMessages
The name of the message attribute, where N is the index.
The name can contain alphanumeric characters and the underscore (
_), hyphen (
-), and period (
The name is case-sensitive and must be unique among all attribute names for the message.
The name must not start with AWS-reserved prefixes such as
Amazon.(or any casing variants).
The name must not start or end with a period (
.), and it should not have periods in succession (
The name can be up to 256 characters long.
ReceiveMessage, you can send a list of attribute names to receive, or you can return all of the attributes by specifying
.* in your request. You can also use all message attributes starting with a prefix, for example
@property (nonatomic, strong) NSArray<NSString*> *messageAttributeNames
The URL of the Amazon SQS queue from which messages are received.
Queue URLs and names are case-sensitive.
@property (nonatomic, strong) NSString *queueUrl
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
ReceiveRequestAttemptIdonly for 5 minutes after a
When you set
FifoQueue, a caller of the
ReceiveMessageaction can provide a
If a caller of the
ReceiveMessageaction doesn't provide a
ReceiveRequestAttemptId, Amazon SQS generates a
You can retry the
ReceiveMessageaction with the same
ReceiveRequestAttemptIdif none of the messages have been modified (deleted or had their visibility changes).
During a visibility timeout, subsequent calls with the same
ReceiveRequestAttemptIdreturn 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
ReceiveMessageaction still processes messages when the visibility timeout expires and messages become visible, another worker consuming from the same queue can receive the same messages and therefore process duplicates. Also, if a consumer 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
MessageGroupIdare invisible, no more messages belonging to the same
MessageGroupIdare returned until the visibility timeout expires. You can still receive messages with another
MessageGroupIdas long as it is also visible.
If a caller of
ReceiveMessagecan't track the
ReceiveRequestAttemptId, no retries work until the original visibility timeout expires. As a result, delays might occur but the messages in the queue remain in a strict order.
The length of
ReceiveRequestAttemptId is 128 characters.
ReceiveRequestAttemptId can contain alphanumeric characters (
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
The duration (in seconds) that the received messages are hidden from subsequent retrieve requests after being retrieved by a
@property (nonatomic, strong) NSNumber *visibilityTimeout
The duration (in seconds) for which the call waits for a message to arrive in the queue before returning. If a message is available, the call returns sooner than
WaitTimeSeconds. If no messages are available and the wait time expires, the call returns successfully with an empty list of messages.
@property (nonatomic, strong) NSNumber *waitTimeSeconds