(Objective-C) 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

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#import <CkoRest.h>
#import <CkoStringBuilder.h>
#import <NSString.h>

// 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.
CkoRest *rest = [[CkoRest alloc] init];
BOOL bAutoReconnect = YES;
BOOL success = [rest Connect: @"<yournamespace>.servicebus.windows.net" port: [NSNumber numberWithInt: 443] tls: YES autoReconnect: bAutoReconnect];
if (success != YES) {
    NSLog(@"%@",rest.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.
CkoStringBuilder *sbToken = [[CkoStringBuilder alloc] init];
[sbToken LoadFile: @"qa_data/tokens/serviceBusSas.txt" charset: @"utf-8"];

// Tell the REST object to use the Azure Shared Access Signature for authorization.
[sbToken Prepend: @"SharedAccessSignature "];
[rest AddHeader: @"Authorization" value: [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.
NSString *topicName = @"gilaMonster";
NSString *subscriptionName = @"feedings";
NSString *messageId = @"7bea513a6ddb49089e07bfbee26d85bd";
NSString *lockToken = @"0a13ee8a-be32-4458-89e0-5e1401caa6a0";

// Build the path..
CkoStringBuilder *sbPath = [[CkoStringBuilder alloc] init];
[sbPath Append: @"/{topicPath}/subscriptions/{subscriptionName}/messages/{messageId|sequenceNumber}/{lockToken}"];
int numReplaced = [[sbPath Replace: @"{topicPath}" replacement: topicName] intValue];
numReplaced = [[sbPath Replace: @"{subscriptionName}" replacement: subscriptionName] intValue];
numReplaced = [[sbPath Replace: @"{messageId|sequenceNumber}" replacement: messageId] intValue];
numReplaced = [[sbPath Replace: @"{lockToken}" replacement: lockToken] intValue];

// Add a timeout parameter.
[rest AddQueryParam: @"timeout" value: @"20"];

// Use the PUT HTTP verb to unlock the message.
CkoStringBuilder *sbResponseBody = [[CkoStringBuilder alloc] init];
success = [rest FullRequestNoBodySb: @"PUT" uriPath: [sbPath GetAsString] sb: sbResponseBody];
if (success != YES) {
    NSLog(@"%@",rest.LastErrorText);
    return;
}

NSLog(@"%@%d",@"Response Status Code = ",[rest.ResponseStatusCode intValue]);

// Check for a success response.
if ([rest.ResponseStatusCode intValue] != 200) {
    NSLog(@"%@",rest.LastRequestStartLine);
    NSLog(@"%@",rest.LastRequestHeader);
    NSLog(@"%@",[sbResponseBody GetAsString]);
    NSLog(@"%@",@"Failed.");
    return;
}

// If successful, the response body would be empty..
NSLog(@"%@",@"Success.");