DataFlex
DataFlex
Azure Service Bus - Peek-Lock Message (Non-Destructive Read)
See more Azure Service Bus Examples
Shows how to atomically retrieve and lock a message from a queue or subscription for processing. The message is guaranteed not to be delivered to other receivers (on the same queue or subscription only) during the lock duration specified in the queue/subscription description.For more information, see https://docs.microsoft.com/en-us/rest/api/servicebus/peek-lock-message-non-destructive-read
Chilkat DataFlex Downloads
Use ChilkatAx-win32.pkg
Procedure Test
Boolean iSuccess
Handle hoRest
Boolean iBAutoReconnect
Handle hoSbToken
String sTopicName
String sSubscriptionName
Handle hoSbPath
Handle hoSbQueuePath
Variant vSbResponseBody
Handle hoSbResponseBody
Handle hoJsonBrokerProps
String sMessage
String sTemp1
Integer iTemp1
Move False To iSuccess
// 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.
Get Create (RefClass(cComChilkatRest)) To hoRest
If (Not(IsComObjectCreated(hoRest))) Begin
Send CreateComObject of hoRest
End
Move True To iBAutoReconnect
Get ComConnect Of hoRest "<yournamespace>.servicebus.windows.net" 443 True iBAutoReconnect To iSuccess
If (iSuccess <> True) Begin
Get ComLastErrorText Of hoRest To sTemp1
Showln sTemp1
Procedure_Return
End
// ----------------------------------------------------------------------------------------------
// 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..
// ----------------------------------------------------------------------------------------------
// 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.
Get Create (RefClass(cComChilkatStringBuilder)) To hoSbToken
If (Not(IsComObjectCreated(hoSbToken))) Begin
Send CreateComObject of hoSbToken
End
Get ComLoadFile Of hoSbToken "qa_data/tokens/serviceBusSas.txt" "utf-8" To iSuccess
// Tell the REST object to use the Azure Shared Access Signature for authorization.
Get ComPrepend Of hoSbToken "SharedAccessSignature " To iSuccess
Get ComGetAsString Of hoSbToken To sTemp1
Get ComAddHeader Of hoRest "Authorization" sTemp1 To iSuccess
// ----------------------------------------------------------------------------------------------
// Peek-lock a message from the subscription "feedings" in the topic "gilaMonster"
Move "gilaMonster" To sTopicName
Move "feedings" To sSubscriptionName
// Build the path..
Get Create (RefClass(cComChilkatStringBuilder)) To hoSbPath
If (Not(IsComObjectCreated(hoSbPath))) Begin
Send CreateComObject of hoSbPath
End
Get ComAppend Of hoSbPath "/" To iSuccess
Get ComAppend Of hoSbPath sTopicName To iSuccess
Get ComAppend Of hoSbPath "/subscriptions/" To iSuccess
Get ComAppend Of hoSbPath sSubscriptionName To iSuccess
Get ComAppend Of hoSbPath "/messages/head" To iSuccess
// If peek-locking from a queue, the path would be built like this:
Get Create (RefClass(cComChilkatStringBuilder)) To hoSbQueuePath
If (Not(IsComObjectCreated(hoSbQueuePath))) Begin
Send CreateComObject of hoSbQueuePath
End
Get ComAppend Of hoSbQueuePath "/" To iSuccess
Get ComAppend Of hoSbQueuePath "queueName" To iSuccess
Get ComAppend Of hoSbQueuePath "/messages/head" To iSuccess
// This example will use the sbPath..
// Add a timeout parameter.
Get ComAddQueryParam Of hoRest "timeout" "20" To iSuccess
// Use the POST HTTP verb to peek-lock the message.
// Note that the only difference between the destructive Read-and-Delete and the non-destructive Peek-Lock
// is that the HTTP verb. (POST is for peek-lock, DELETE is fore read-and-delete.)
Get Create (RefClass(cComChilkatStringBuilder)) To hoSbResponseBody
If (Not(IsComObjectCreated(hoSbResponseBody))) Begin
Send CreateComObject of hoSbResponseBody
End
Get ComGetAsString Of hoSbPath To sTemp1
Get pvComObject of hoSbResponseBody to vSbResponseBody
Get ComFullRequestNoBodySb Of hoRest "POST" sTemp1 vSbResponseBody To iSuccess
If (iSuccess <> True) Begin
Get ComLastErrorText Of hoRest To sTemp1
Showln sTemp1
Procedure_Return
End
Get ComResponseStatusCode Of hoRest To iTemp1
Showln "Response Status Code = " iTemp1
// Check for a success response.
// CAREFUL: This returns a 201 response instead of a 200 response. In general, either 200 or 201 should always indicate success.
Get ComResponseStatusCode Of hoRest To iTemp1
If (iTemp1 <> 201) Begin
Get ComLastRequestStartLine Of hoRest To sTemp1
Showln sTemp1
Get ComLastRequestHeader Of hoRest To sTemp1
Showln sTemp1
Get ComGetAsString Of hoSbResponseBody To sTemp1
Showln sTemp1
Showln "Failed."
Procedure_Return
End
// The content of the message is returned in the HTTP response body.
// The HTTP response headers contains extra information. For example:
Get Create (RefClass(cComChilkatJsonObject)) To hoJsonBrokerProps
If (Not(IsComObjectCreated(hoJsonBrokerProps))) Begin
Send CreateComObject of hoJsonBrokerProps
End
Get ComResponseHdrByName Of hoRest "BrokerProperties" To sTemp1
Get ComLoad Of hoJsonBrokerProps sTemp1 To iSuccess
Set ComEmitCompact Of hoJsonBrokerProps To False
Get ComEmit Of hoJsonBrokerProps To sTemp1
Showln sTemp1
// An example of the BrokerProperties JSON that is returned:
// {
// "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
// }
// Also the "Location" response header contains the URI of the locked message.
// This can be used to ulock or delete the message.
Get ComResponseHdrByName Of hoRest "Location" To sTemp1
Showln "Location: " sTemp1
// An example of the Location URI:
// https://chilkat.servicebus.windows.net/gilamonster/subscriptions/feedings/messages/3/0a13ee8a-be32-4458-89e0-5e1401caa6a0
// If successful, the message is the contents of the response body.
Get ComGetAsString Of hoSbResponseBody To sMessage
Showln "Received message: " sMessage
Showln "Success."
End_Procedure