DataFlex

Getting the HTTP Response after an Asynchronous HTTP Request Completes

See more HTTP Examples

Some HTTP methods return an HTTP response object. This example demonstrates how to obtain the HTTP response object for such a method when calling asynchronously. DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoHttp
    Variant vTask
    Handle hoTask
    Handle hoResp
    String sTemp1
    Integer iTemp1
    Boolean bTemp1

    Move False To iSuccess

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

    Move False To iSuccess

    Get Create (RefClass(cComChilkatHttp)) To hoHttp
    If (Not(IsComObjectCreated(hoHttp))) Begin
        Send CreateComObject of hoHttp
    End

    // Call the async version of the QuickGetObj method to return a task object.
    // The task object is loaded, but is in the Inert state -- meaning it is
    // not yet scheduled to run on Chilkat's background thread pool.
    Get ComQuickGetObjAsync Of hoHttp "https://stackexchange.com" To vTask
    If (IsComObject(vTask)) Begin
        Get Create (RefClass(cComChilkatTask)) To hoTask
        Set pvComObject Of hoTask To vTask
    End
    Get ComLastMethodSuccess Of hoHttp To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoHttp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Schedule the task for running on the thread pool.  This changes the task's state
    // from Inert to Live.
    Get ComRun Of hoTask To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoTask To sTemp1
        Showln sTemp1
        Send Destroy of hoTask
        Procedure_Return
    End

    // The application is now free to do anything else
    // while the HTML page is being downloaded.

    // For this example, we'll simply sleep and periodically
    // check to see if the QuickGetObjAsync if finished.
    While ((ComFinished(hoTask)) <> True)

        // Sleep 100 ms.
        Send ComSleepMs To hoTask 100

    Loop

    // A finished task could be one that was canceled, aborted, or truly finished.  

    // If the task was "canceled", it was canceled prior to actually starting.  This could
    // happen if the task was canceled while waiting in a thread pool queue to be scheduled by Chilkat's
    // background thread pool scheduler.  

    // If the task was "aborted", it indicates that it was canceled while running in a background thread.  
    // The ResultErrorText will likely indicate that the task was aborted.

    // If the task "completed", then it ran to completion, but the actual success/failure of the method
    // is determined by the result obtained via a GetResult* method.  (A "completed" task will
    // have a StatusInt equal to 7.   If the task finished, but was not completed, then it must've
    // been aborted or canceled:
    Get ComStatusInt Of hoTask To iTemp1
    If (iTemp1 <> 7) Begin
        Showln "Task did not complete."
        Get ComStatus Of hoTask To sTemp1
        Showln "task status: " sTemp1
        Send Destroy of hoTask
        Procedure_Return
    End

    // The synchronous call to QuickGetObj would return an HTTP response object.  To get this 
    // response object for the async call, we instantiate a new/empty HTTP response object,
    // and then load it from the completed task.
    Get Create (RefClass(cComChilkatHttpResponse)) To hoResp
    If (Not(IsComObjectCreated(hoResp))) Begin
        Send CreateComObject of hoResp
    End

    Get ComLoadTaskResult Of hoResp vTask To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoResp To sTemp1
        Showln sTemp1
        Send Destroy of hoTask
        Procedure_Return
    End

    Send Destroy of hoTask

    // Now that we have the response, we can get all of the information:

    Get ComStatusCode Of hoResp To iTemp1
    Showln "status code: " iTemp1
    Get ComHeader Of hoResp To sTemp1
    Showln "response header: " sTemp1

    // ..


End_Procedure