Azure + Node Js Service总线持久订阅主题

Question

Using node js i want to create persistent subscription for Azure service bus service topic. right now it is execute only once. Please guide me I am new to this. Thanks in advance. I am using following code to subscribe topic.

var azure = require('azure');

var azureConnection = "Endpoint=sb:My connection string"

var retryOperations = new azure.ExponentialRetryPolicyFilter();
var serviceBusService = azure.createServiceBusService(azureConnection).withFilter(retryOperations);

serviceBusService.receiveSubscriptionMessage('mytopic01', 'mytopicsub', function (error, receivedMessage) {

    if (!error) {
        // // // Message received and deleted
        console.log(receivedMessage);
    }
});

Also I don't want to use setInterval function. I want to solution if message publish to the topic it should automatically trigger subscription.

Answer 1

Actually, if your client application is an independent node.js application, we usually set up a cycle program to receive message from service bus in loop. EG

var azure = require('azure');
var sbService = azure.createServiceBusService(<connection_string>);
function checkForMessages(sbService, queueName, callback) {
  sbService.receiveSubscriptionMessage(queueName, { isPeekLock: true }, function (err, lockedMessage) {
    if (err) {
      if (err === 'No messages to receive') {
        console.log('No messages');
      } else {
        callback(err);
      }
    } else {
      callback(null, lockedMessage);
    }
  });
}
function processMessage(sbService, err, lockedMsg) {
  if (err) {
    console.log('Error on Rx: ', err);
  } else {
    console.log('Rx: ', lockedMsg);
    sbService.deleteMessage(lockedMsg, function(err2) {
      if (err2) {
        console.log('Failed to delete message: ', err2);
      } else {
        console.log('Deleted message.');
      }
    })
  }
}
setInterval(checkForMessages.bind(null, sbService, queueName, processMessage.bind(null, sbService)), 5000);

You can refer to the code sample in the similar scenario at GitHub provided by Azure Team.

Any further concern, please feel free to let me know.