Dart

Azure Service Bus - Unlock Message

See more Azure Service Bus Examples

Shows how to unlock a message for processing by other receivers on a specified queue or subscription. This operation deletes the lock object, causing the message to be unlocked.

For more information, see https://docs.microsoft.com/en-us/rest/api/servicebus/unlock-message

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Note: Requires Chilkat v9.5.0.65 or greater.

  // This requires the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  // Make the initial connection.
  // A single REST object, once connected, can be used for many Azure Service Bus REST API calls.
  // The auto-reconnect indicates that if the already-established HTTPS connection is closed,
  // then it will be automatically re-established as needed.
  final rest = CkRest();
  final bAutoReconnect = true;
  try {
    rest.connect('<yournamespace>.servicebus.windows.net', 443, true, bAutoReconnect);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Let's load a previously computed SAS token and use it.
  // See Azure Shared Access Signature for an example to genenerate an Azure SAS token.
  final sbToken = CkStringBuilder();
  sbToken.loadFile('qa_data/tokens/serviceBusSas.txt', 'utf-8');

  // Tell the REST object to use the Azure Shared Access Signature for authorization.
  sbToken.prepend('SharedAccessSignature ');
  rest.addHeader('Authorization', sbToken.getAsString());

  // ----------------------------------------------------------------------------------------------
  // The code above this comment could be placed inside a function/subroutine within the application
  // because the connection does not need to be made for every request.  Once the connection is made
  // the app may send many requests..
  // ----------------------------------------------------------------------------------------------

  // To unlock a message, we'll need either the SequenceNumber or MessageId.
  // When the message was locked, the SequenceNumber and MessageId of the locked message
  // was returned in the HTTP response header named "BrokerProperties, which contained
  // JSON such as the following:

  // 	{
  // 	  "DeliveryCount": 2,
  // 	  "EnqueuedSequenceNumber": 3000003,
  // 	  "EnqueuedTimeUtc": "Wed, 07 Dec 2016 17:42:48 GMT",
  // 	  "Label": "M2",
  // 	  "LockToken": "0a13ee8a-be32-4458-89e0-5e1401caa6a0",
  // 	  "LockedUntilUtc": "Wed, 07 Dec 2016 18:13:12 GMT",
  // 	  "MessageId": "7bea513a6ddb49089e07bfbee26d85bd",
  // 	  "SequenceNumber": 3,
  // 	  "State": "Active",
  // 	  "TimeToLive": 922337203685.47754
  // 	}

  // The path for unlocking a message is constructed as follows, depending on
  // whether it is a message on a queue or subscription:
  // 
  // (for a queue)
  // /{queuePath}/messages/{messageId|sequenceNumber}/{lockToken}
  // 
  // (for a subscription)
  // /{topicPath}/subscriptions/{subscriptionName}/messages/{messageId|sequenceNumber}/{lockToken}

  // This example will build a path to unlock a message contained in a subscription.
  final topicName = 'gilaMonster';
  final subscriptionName = 'feedings';
  final messageId = '7bea513a6ddb49089e07bfbee26d85bd';
  final lockToken = '0a13ee8a-be32-4458-89e0-5e1401caa6a0';

  // Build the path..
  final sbPath = CkStringBuilder();
  sbPath.append('/{topicPath}/subscriptions/{subscriptionName}/messages/{messageId|sequenceNumber}/{lockToken}');
  var numReplaced = sbPath.replace('{topicPath}', topicName);
  numReplaced = sbPath.replace('{subscriptionName}', subscriptionName);
  numReplaced = sbPath.replace('{messageId|sequenceNumber}', messageId);
  numReplaced = sbPath.replace('{lockToken}', lockToken);

  // Add a timeout parameter.
  rest.addQueryParam('timeout', '20');

  // Use the PUT HTTP verb to unlock the message.
  final sbResponseBody = CkStringBuilder();
  try {
    rest.fullRequestNoBodySb('PUT', sbPath.getAsString(), sbResponseBody);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Response Status Code = ${rest.responseStatusCode}');

  // Check for a success response.
  if (rest.responseStatusCode != 200) {
    print(rest.lastRequestStartLine);
    print(rest.lastRequestHeader);
    print(sbResponseBody.getAsString());
    print('Failed.');
    return;
  }

  // If successful, the response body would be empty..
  print('Success.');
}