Copyright | (c) 2013-2016 Brendan Hay |
---|---|
License | Mozilla Public License, v. 2.0. |
Maintainer | Brendan Hay <brendan.g.hay@gmail.com> |
Stability | auto-generated |
Portability | non-portable (GHC extensions) |
Safe Haskell | None |
Language | Haskell2010 |
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.
- receiveMessage :: Text -> ReceiveMessage
- data ReceiveMessage
- rmVisibilityTimeout :: Lens' ReceiveMessage (Maybe Int)
- rmMessageAttributeNames :: Lens' ReceiveMessage [Text]
- rmWaitTimeSeconds :: Lens' ReceiveMessage (Maybe Int)
- rmAttributeNames :: Lens' ReceiveMessage [MessageAttribute]
- rmMaxNumberOfMessages :: Lens' ReceiveMessage (Maybe Int)
- rmQueueURL :: Lens' ReceiveMessage Text
- receiveMessageResponse :: Int -> ReceiveMessageResponse
- data ReceiveMessageResponse
- rmrsMessages :: Lens' ReceiveMessageResponse [Message]
- rmrsResponseStatus :: Lens' ReceiveMessageResponse Int
Creating a Request
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:
data ReceiveMessage Source
See: receiveMessage
smart constructor.
Request Lenses
rmVisibilityTimeout :: Lens' ReceiveMessage (Maybe Int) Source
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] Source
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) Source
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] Source
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) Source
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 Source
The URL of the Amazon SQS queue to take action on.
Destructuring the Response
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:
data ReceiveMessageResponse Source
A list of received messages.
See: receiveMessageResponse
smart constructor.
Response Lenses
rmrsMessages :: Lens' ReceiveMessageResponse [Message] Source
A list of messages.
rmrsResponseStatus :: Lens' ReceiveMessageResponse Int Source
The response status code.