AWS SDK Version 2 for .NET
API Reference

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.NET Framework 4.5
 
Container for the parameters to the ReceiveMessage operation. 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:

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.

Inheritance Hierarchy

System.Object
  Amazon.Runtime.AmazonWebServiceRequest
    Amazon.SQS.AmazonSQSRequest
      Amazon.SQS.Model.ReceiveMessageRequest

Namespace: Amazon.SQS.Model
Assembly: AWSSDK.dll
Version: (assembly version)

Syntax

C#
public class ReceiveMessageRequest : AmazonSQSRequest
         IRequestEvents

The ReceiveMessageRequest type exposes the following members

Constructors

NameDescription
Public Method ReceiveMessageRequest() Empty constructor used to set properties independently even when a simple constructor is available
Public Method ReceiveMessageRequest(string) Instantiates ReceiveMessageRequest with the parameterized properties

Properties

NameTypeDescription
Public Property AttributeNames System.Collections.Generic.List<System.String> Gets and sets the property AttributeNames.

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).
Public Property MaxNumberOfMessages System.Int32 Gets and sets the property MaxNumberOfMessages.

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.

Public Property MessageAttributeNames System.Collections.Generic.List<System.String> Gets and sets the property 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 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.

Public Property QueueUrl System.String Gets and sets the property QueueUrl.

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

Public Property VisibilityTimeout System.Int32 Gets and sets the property VisibilityTimeout.

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

Public Property WaitTimeSeconds System.Int32 Gets and sets the property 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.

Examples

This example shows how to receive a message.

Receive message example

var client = new AmazonSQSClient();

var request = new ReceiveMessageRequest
{
  AttributeNames = new List<string>() { "All" },
  MaxNumberOfMessages = 5,
  QueueUrl = "https://sqs.us-east-1.amazonaws.com/80398EXAMPLE/MyTestQueue",
  VisibilityTimeout = (int)TimeSpan.FromMinutes(10).TotalSeconds,
  WaitTimeSeconds = (int)TimeSpan.FromSeconds(5).TotalSeconds
};

var response = client.ReceiveMessage(request);

if (response.Messages.Count > 0)
{
  foreach (var message in response.Messages)
  {
    Console.WriteLine("For message ID '" + message.MessageId + "':");
    Console.WriteLine("  Body: " + message.Body);
    Console.WriteLine("  Receipt handle: " + message.ReceiptHandle);
    Console.WriteLine("  MD5 of body: " + message.MD5OfBody);
    Console.WriteLine("  MD5 of message attributes: " +
      message.MD5OfMessageAttributes);
    Console.WriteLine("  Attributes:");

    foreach (var attr in message.Attributes)
    {
      Console.WriteLine("    " + attr.Key + ": " + attr.Value);
    }
  }
}
else
{
  Console.WriteLine("No messages received.");
}
      

Version Information

.NET Framework:
Supported in: 4.5, 4.0, 3.5

.NET for Windows Store apps:
Supported in: Windows 8.1, Windows 8

.NET for Windows Phone:
Supported in: Windows Phone 8.1, Windows Phone 8