DataFlex

REST Asynchronous Streaming Upload File

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Demonstrates how to asynchronous streaming upload a file to cloud storage. This particular example demonstrates an upload to the Azure Cloud Storage service. The same concepts apply to S3, Google Cloud, and Google Drive. DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoRest
    Boolean iBTls
    Integer iPort
    Boolean iBAutoReconnect
    Variant vAzAuth
    Handle hoAzAuth
    Variant vSendStream
    Handle hoSendStream
    Variant vTask
    Handle hoTask
    Integer iCurPctDone
    Integer iResponseStatusCode
    String sResponseBodyStr
    String sTemp1
    Integer iTemp1
    Boolean bTemp1

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatRest)) To hoRest
    If (Not(IsComObjectCreated(hoRest))) Begin
        Send CreateComObject of hoRest
    End

    // Connect to the Azure Storage Blob Service
    Move True To iBTls
    Move 443 To iPort
    Move True To iBAutoReconnect
    // In this example, the storage account name is "chilkat".
    Get ComConnect Of hoRest "chilkat.blob.core.windows.net" iPort iBTls iBAutoReconnect To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoRest To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Provide Azure Cloud credentials for the REST call.
    Get Create (RefClass(cComChilkatAuthAzureStorage)) To hoAzAuth
    If (Not(IsComObjectCreated(hoAzAuth))) Begin
        Send CreateComObject of hoAzAuth
    End
    Set ComAccessKey Of hoAzAuth To "AZURE_ACCESS_KEY"
    // The account name used here should match the 1st part of the domain passed in the call to Connect (above).
    Set ComAccount Of hoAzAuth To "chilkat"
    Set ComScheme Of hoAzAuth To "SharedKey"
    Set ComService Of hoAzAuth To "Blob"
    // This causes the "x-ms-version: 2021-08-06" header to be automatically added.
    Set ComXMsVersion Of hoAzAuth To "2021-08-06"
    Get pvComObject of hoAzAuth to vAzAuth
    Get ComSetAuthAzureStorage Of hoRest vAzAuth To iSuccess

    // Set some request headers.
    Get ComAddHeader Of hoRest "x-ms-blob-content-disposition" 'attachment; filename="thisIsATest.txt"' To iSuccess
    Get ComAddHeader Of hoRest "x-ms-blob-type" "BlockBlob" To iSuccess
    Get ComAddHeader Of hoRest "x-ms-meta-m1" "v1" To iSuccess
    Get ComAddHeader Of hoRest "x-ms-meta-m2" "v2" To iSuccess

    // Note: The application does not need to explicitly set the following
    // headers: x-ms-date, Authorization, and Content-Length.  These headers
    // are automatically set by Chilkat.

    Get Create (RefClass(cComChilkatStream)) To hoSendStream
    If (Not(IsComObjectCreated(hoSendStream))) Begin
        Send CreateComObject of hoSendStream
    End

    // Define the source data for the stream to be a file.
    Set ComSourceFile Of hoSendStream To "qa_data/hamlet.xml"

    // Create a background thread task to upload from the stream
    // The name of the Azure storage container is "test".
    Get pvComObject of hoSendStream to vSendStream
    Get ComFullRequestStreamAsync Of hoRest "PUT" "/test/thisIsATest.txt" vSendStream To vTask
    If (IsComObject(vTask)) Begin
        Get Create (RefClass(cComChilkatTask)) To hoTask
        Set pvComObject Of hoTask To vTask
    End

    // Start the task. 
    Get ComRun Of hoTask To iSuccess

    // In this example, we'll simply sleep and periodically
    // check to see if the REST upload if finished.
    Move 0 To iCurPctDone
    While ((ComFinished(hoTask)) <> True)
        Send ComSleepMs To hoTask 100
    Loop

    // Check to see if the call to FullRequestStream in the background thread pool succeeded.
    Get ComTaskSuccess Of hoTask To bTemp1
    If (bTemp1 <> True) Begin
        // Show what would've been the LastErrorText had FullRequestStream been called synchronously
        Get ComResultErrorText Of hoTask To sTemp1
        Showln sTemp1
        Send Destroy of hoTask
        Procedure_Return
    End

    Get ComResponseStatusCode Of hoRest To iResponseStatusCode

    // When successful, the Azure Storage service will respond with a 201 response code,
    // with an empty body.  Therefore, in the success condition, the responseStr is empty.
    If (iResponseStatusCode = 201) Begin
        Showln "File uploaded."
    End
    Else Begin
        // It failed, so examine the response body, if one was returned:
        // Given that FullRequestStream returns a string, the return value is obtained via GetResultString.
        Get ComGetResultString Of hoTask To sResponseBodyStr
        Showln "response body (if any): " sResponseBodyStr

        // Examine the request/response to see what happened.
        Get ComResponseStatusCode Of hoRest To iTemp1
        Showln "response status code = " iTemp1
        Get ComResponseStatusText Of hoRest To sTemp1
        Showln "response status text = " sTemp1
        Get ComResponseHeader Of hoRest To sTemp1
        Showln "response header: " sTemp1
        Showln "---"
        Get ComLastRequestStartLine Of hoRest To sTemp1
        Showln "LastRequestStartLine: " sTemp1
        Get ComLastRequestHeader Of hoRest To sTemp1
        Showln "LastRequestHeader: " sTemp1
    End

    Send Destroy of hoTask


End_Procedure