Network.AWS.SQS.ReceiveMessage

Retrieves one or more messages, with a maximum limit of 10 messages, from the specified queue. Long poll support is enabled by using the WaitTimeSeconds parameter. For more information, see Amazon SQS Long Poll in the Amazon SQS Developer Guide.

Short poll is the default behavior where a weighted random set of machines is sampled on a ReceiveMessage call. This means only the messages on the sampled machines are returned. If the number of messages in the queue is small (less than 1000), it is likely you will get fewer messages than you requested per ReceiveMessage call. If the number of messages in the queue is extremely small, you might not receive any messages in a particular ReceiveMessage response; in which case you should repeat the request.

For each message returned, the response includes the following:

• Message body
• MD5 digest of the message body. For information about MD5, go to http://www.faqs.org/rfcs/rfc1321.html.
• Message ID you received when you sent the message to the queue.
• Receipt handle.
• Message attributes.
• MD5 digest of the message attributes.

The receipt handle is the identifier you must provide when deleting the message. For more information, see Queue and Message Identifiers in the Amazon SQS Developer Guide.

You can provide the VisibilityTimeout parameter in your request, which will be applied to the messages that Amazon SQS returns in the response. If you do not include the parameter, the overall visibility timeout for the queue is used for the returned messages. For more information, see Visibility Timeout in the Amazon SQS Developer Guide.

Going forward, new attributes might be added. If you are writing code that calls this action, we recommend that you structure your code so that it can handle new attributes gracefully.

Creating a Request

receiveMessage

Arguments

:: Text

rmQueueURL

-> ReceiveMessage

Creates a value of ReceiveMessage with the minimum fields required to make a request.

Use one of the following lenses to modify other fields as desired:

• rmVisibilityTimeout
• rmMessageAttributeNames
• rmWaitTimeSeconds
• rmAttributeNames
• rmMaxNumberOfMessages
• rmQueueURL

data ReceiveMessage

See: receiveMessage smart constructor.

Instances

Eq ReceiveMessage

Data ReceiveMessage

Read ReceiveMessage

Show ReceiveMessage

Generic ReceiveMessage

Hashable ReceiveMessage

AWSRequest ReceiveMessage

ToPath ReceiveMessage

ToHeaders ReceiveMessage

ToQuery ReceiveMessage

type Rep ReceiveMessage

type Rs ReceiveMessage = ReceiveMessageResponse

Request Lenses

rmVisibilityTimeout :: Lens' ReceiveMessage (Maybe Int)

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

rmMessageAttributeNames :: Lens' ReceiveMessage [Text]

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 cannot 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 "foo.*" to return all message attributes starting with the "foo" prefix.

rmWaitTimeSeconds :: Lens' ReceiveMessage (Maybe Int)

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.

rmAttributeNames :: Lens' ReceiveMessage [MessageAttribute]

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

The following lists the names and descriptions of the attributes that can be returned:

• All - returns all values.
• ApproximateFirstReceiveTimestamp - returns the time when 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 - returns the AWS account number (or the IP address, if anonymous access is allowed) of the sender.
• SentTimestamp - returns the time when the message was sent to the queue (epoch time in milliseconds).

rmMaxNumberOfMessages :: Lens' ReceiveMessage (Maybe Int)

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

All of the messages are not necessarily returned.

rmQueueURL :: Lens' ReceiveMessage Text

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

Destructuring the Response

receiveMessageResponse

Arguments

:: Int

rmrsResponseStatus

-> ReceiveMessageResponse

Creates a value of ReceiveMessageResponse with the minimum fields required to make a request.

Use one of the following lenses to modify other fields as desired:

• rmrsMessages
• rmrsResponseStatus

data ReceiveMessageResponse

A list of received messages.

See: receiveMessageResponse smart constructor.

Instances

Eq ReceiveMessageResponse

Data ReceiveMessageResponse

Read ReceiveMessageResponse

Show ReceiveMessageResponse

Generic ReceiveMessageResponse

type Rep ReceiveMessageResponse

Response Lenses

rmrsMessages :: Lens' ReceiveMessageResponse [Message]

A list of messages.

rmrsResponseStatus :: Lens' ReceiveMessageResponse Int

The response status code.