(DataFlex) Initiate Multipart S3 Upload

Initiates an Amazon AWS multipart S3 upload.

The following is quoted from the Amazon Simple Storage Service Documentation:

"The Multipart upload API enables you to upload large objects in parts. You can use this API to upload new large objects or make a copy of an existing object (see Operations on Objects).

Multipart uploading is a three-step process: You initiate the upload, you upload the object parts, and after you have uploaded all the parts, you complete the multipart upload. Upon receiving the complete multipart upload request, Amazon S3 constructs the object from the uploaded parts, and you can then access the object just as you would any other object in your bucket.

You can list of all your in-progress multipart uploads or get a list of the parts that you have uploaded for a specific multipart upload. Each of these operations is explained in this section.

Multipart Upload Initiation

When you send a request to initiate a multipart upload, Amazon S3 returns a response with an upload ID, which is a unique identifier for your multipart upload. You must include this upload ID whenever you upload parts, list the parts, complete an upload, or abort an upload. If you want to provide any metadata describing the object being uploaded, you must provide it in the request to initiate multipart upload."

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Use ChilkatAx-win32.pkg

Procedure Test
    Handle hoRest
    Boolean iBTls
    Integer iPort
    Boolean iBAutoReconnect
    Boolean iSuccess
    Variant vAuthAws
    Handle hoAuthAws
    String sFileToUploadPath
    String sResponseXml
    Handle hoXml
    String sTemp1
    Integer iTemp1
    Boolean bTemp1

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

    // Other S3 Multipart Upload Examples:
    // S3 Upload Parts
    // Complete Multipart Upload
    // Abort Multipart Upload
    // List Parts

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

    // Connect to the Amazon AWS REST server.
    Move True To iBTls
    Move 443 To iPort
    Move True To iBAutoReconnect
    Get ComConnect Of hoRest "s3.amazonaws.com" iPort iBTls iBAutoReconnect To iSuccess

    // ----------------------------------------------------------------------------
    // Important: For buckets created in regions outside us-east-1,
    // there are three important changes that need to be made.
    // See Working with S3 Buckets in Non-us-east-1 Regions for the details.
    // ----------------------------------------------------------------------------

    // Provide AWS credentials for the REST call.
    Get Create (RefClass(cComChilkatAuthAws)) To hoAuthAws
    If (Not(IsComObjectCreated(hoAuthAws))) Begin
        Send CreateComObject of hoAuthAws
    End
    Set ComAccessKey Of hoAuthAws To "AWS_ACCESS_KEY"
    Set ComSecretKey Of hoAuthAws To "AWS_SECRET_KEY"
    Set ComServiceName Of hoAuthAws To "s3"

    Get pvComObject of hoAuthAws to vAuthAws
    Get ComSetAuthAws Of hoRest vAuthAws To iSuccess

    // Set the bucket name via the HOST header.
    // In this case, the bucket name is "chilkat100".
    Set ComHost Of hoRest To "chilkat100.s3.amazonaws.com"

    // The local file path (on our local system) to upload.
    Move "s3_multipart_uploads/somethingBig.zip" To sFileToUploadPath

    // The HTTP request to initiate a multipart upload is a POST with no body content..
    // This is the tricky part: We would be tempted to pass "/somethingBig.zip?uploads"
    // in the 2nd argument to FullRequestNoBody.  However, we must pass only the path without query
    // params.  The "uploads" query param must be added via AddQueryParam.  This allows it to be included
    // in the AWS signature calculation for authentication.
    Get ComAddQueryParam Of hoRest "uploads" "" To iSuccess
    Get ComFullRequestNoBody Of hoRest "POST" "/somethingBig.zip" To sResponseXml
    Get ComLastMethodSuccess Of hoRest To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoRest To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // When successful, the S3 Storage service will respond with a 200 response code,
    // with an XML body.  
    Get ComResponseStatusCode Of hoRest To iTemp1
    If (iTemp1 <> 200) Begin
        // 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 "response body: " sResponseXml
        Showln "---"
        Get ComLastRequestStartLine Of hoRest To sTemp1
        Showln "LastRequestStartLine: " sTemp1
        Get ComLastRequestHeader Of hoRest To sTemp1
        Showln "LastRequestHeader: " sTemp1
    End

    // See http://docs.aws.amazon.com/AmazonS3/latest/API/mpUploadInitiate.html 
    // for a sample of the XML response.
    Showln sResponseXml
    Showln "----"

    // Save the XML response to a file, and show the UploadId..
    Get Create (RefClass(cComChilkatXml)) To hoXml
    If (Not(IsComObjectCreated(hoXml))) Begin
        Send CreateComObject of hoXml
    End
    Get ComLoadXml Of hoXml sResponseXml To iSuccess
    Get ComSaveXml Of hoXml "s3_multipart_uploads/initiate.xml" To iSuccess

    Get ComGetChildContent Of hoXml "UploadId" To sTemp1
    Showln "UploadId = " sTemp1
    Showln "Multipart upload initiated."


End_Procedure