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# Enabling Long Polling in Amazon SQS
![\[JavaScript code example that applies to Node.js execution\]](http://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/images/nodeicon.png)
**This Node.js code example shows:**
+ How to enable long polling for a newly created queue
+ How to enable long polling for an existing queue
+ How to enable long polling upon receipt of a message
## The Scenario
Long polling reduces the number of empty responses by allowing Amazon SQS to wait a specified time for a message to become available in the queue before sending a response. Also, long polling eliminates false empty responses by querying all of the servers instead of a sampling of servers. To enable long polling, you must specify a non-zero wait time for received messages. You can do this by setting the `ReceiveMessageWaitTimeSeconds` parameter of a queue or by setting the `WaitTimeSeconds` parameter on a message when it is received.
In this example, a series of Node.js modules are used to enable long polling. The Node.js modules use the SDK for JavaScript to enable long polling using these methods of the `AWS.SQS` client class:
+ [https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/SQS.html#setQueueAttributes-property](https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/SQS.html#setQueueAttributes-property)
+ [https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/SQS.html#receiveMessage-property](https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/SQS.html#receiveMessage-property)
+ [https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/SQS.html#createQueue-property](https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/SQS.html#createQueue-property)
For more information about Amazon SQS long polling, see [Long Polling](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-long-polling.html) in the *Amazon Simple Queue Service Developer Guide*.
## Prerequisite Tasks
To set up and run this example, you must first complete these tasks:
+ Install Node.js. For more information about installing Node.js, see the [Node.js website](https://nodejs.org).
+ Create a shared configurations file with your user credentials. For more information about providing a shared credentials file, see [Loading Credentials in Node.js from the Shared Credentials File](loading-node-credentials-shared.md).
## Enabling Long Polling When Creating a Queue
Create a Node.js module with the file name `sqs_longpolling_createqueue.js`. Be sure to configure the SDK as previously shown. To access Amazon SQS, create an `AWS.SQS` service object. Create a JSON object containing the parameters needed to create a queue, including a non-zero value for the `ReceiveMessageWaitTimeSeconds` parameter. Call the `createQueue` method. Long polling is then enabled for the queue.
```
// Load the AWS SDK for Node.js
var AWS = require("aws-sdk");
// Set the region
AWS.config.update({ region: "REGION" });
// Create the SQS service object
var sqs = new AWS.SQS({ apiVersion: "2012-11-05" });
var params = {
QueueName: "SQS_QUEUE_NAME",
Attributes: {
ReceiveMessageWaitTimeSeconds: "20",
},
};
sqs.createQueue(params, function (err, data) {
if (err) {
console.log("Error", err);
} else {
console.log("Success", data.QueueUrl);
}
});
```
To run the example, type the following at the command line.
```
node sqs_longpolling_createqueue.js
```
This sample code can be found [here on GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/master/javascript/example_code/sqs/sqs_longpolling_createqueue.js).
## Enabling Long Polling on an Existing Queue
Create a Node.js module with the file name `sqs_longpolling_existingqueue.js`. Be sure to configure the SDK as previously shown. To access Amazon Simple Queue Service, create an `AWS.SQS` service object. Create a JSON object containing the parameters needed to set the attributes of queue, including a non-zero value for the `ReceiveMessageWaitTimeSeconds` parameter and the URL of the queue. Call the `setQueueAttributes` method. Long polling is then enabled for the queue.
```
// Load the AWS SDK for Node.js
var AWS = require("aws-sdk");
// Set the region
AWS.config.update({ region: "REGION" });
// Create the SQS service object
var sqs = new AWS.SQS({ apiVersion: "2012-11-05" });
var params = {
Attributes: {
ReceiveMessageWaitTimeSeconds: "20",
},
QueueUrl: "SQS_QUEUE_URL",
};
sqs.setQueueAttributes(params, function (err, data) {
if (err) {
console.log("Error", err);
} else {
console.log("Success", data);
}
});
```
To run the example, type the following at the command line.
```
node sqs_longpolling_existingqueue.js
```
This sample code can be found [here on GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/master/javascript/example_code/sqs/sqs_longpolling_existingqueue.js).
## Enabling Long Polling on Message Receipt
Create a Node.js module with the file name `sqs_longpolling_receivemessage.js`. Be sure to configure the SDK as previously shown. To access Amazon Simple Queue Service, create an `AWS.SQS` service object. Create a JSON object containing the parameters needed to receive messages, including a non-zero value for the `WaitTimeSeconds` parameter and the URL of the queue. Call the `receiveMessage` method.
```
// Load the AWS SDK for Node.js
var AWS = require("aws-sdk");
// Set the region
AWS.config.update({ region: "REGION" });
// Create the SQS service object
var sqs = new AWS.SQS({ apiVersion: "2012-11-05" });
var queueURL = "SQS_QUEUE_URL";
var params = {
AttributeNames: ["SentTimestamp"],
MaxNumberOfMessages: 1,
MessageAttributeNames: ["All"],
QueueUrl: queueURL,
WaitTimeSeconds: 20,
};
sqs.receiveMessage(params, function (err, data) {
if (err) {
console.log("Error", err);
} else {
console.log("Success", data);
}
});
```
To run the example, type the following at the command line.
```
node sqs_longpolling_receivemessage.js
```
This sample code can be found [here on GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/master/javascript/example_code/sqs/sqs_longpolling_receivemessage.js).