(SQL Server) REST Asynchronous Streaming Upload

Demonstrates how to create and write to a stream that feeds an asynchronous upload 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.

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

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @iTmp0 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    -- This example requires the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    DECLARE @rest int
    -- Use "Chilkat_9_5_0.Rest" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Rest', @rest OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- Connect to the Azure Storage Blob Service
    DECLARE @bTls int
    SELECT @bTls = 1
    DECLARE @port int
    SELECT @port = 443
    DECLARE @bAutoReconnect int
    SELECT @bAutoReconnect = 1
    -- In this example, the storage account name is "chilkat".
    DECLARE @success int
    EXEC sp_OAMethod @rest, 'Connect', @success OUT, 'chilkat.blob.core.windows.net', @port, @bTls, @bAutoReconnect
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @rest, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @rest
        RETURN
      END

    -- Provide Azure Cloud credentials for the REST call.
    DECLARE @azAuth int
    -- Use "Chilkat_9_5_0.AuthAzureStorage" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.AuthAzureStorage', @azAuth OUT

    EXEC sp_OASetProperty @azAuth, 'AccessKey', 'AZURE_ACCESS_KEY'
    -- The account name used here should match the 1st part of the domain passed in the call to Connect (above).
    EXEC sp_OASetProperty @azAuth, 'Account', 'chilkat'
    EXEC sp_OASetProperty @azAuth, 'Scheme', 'SharedKey'
    EXEC sp_OASetProperty @azAuth, 'Service', 'Blob'
    -- This causes the "x-ms-version: 2021-08-06" header to be automatically added.
    EXEC sp_OASetProperty @azAuth, 'XMsVersion', '2021-08-06'
    EXEC sp_OAMethod @rest, 'SetAuthAzureStorage', @success OUT, @azAuth

    -- Set some request headers.
    EXEC sp_OAMethod @rest, 'AddHeader', @success OUT, 'x-ms-blob-content-disposition', 'attachment; filename="thisIsATest.txt"'
    EXEC sp_OAMethod @rest, 'AddHeader', @success OUT, 'x-ms-blob-type', 'BlockBlob'
    EXEC sp_OAMethod @rest, 'AddHeader', @success OUT, 'x-ms-meta-m1', 'v1'
    EXEC sp_OAMethod @rest, 'AddHeader', @success OUT, 'x-ms-meta-m2', 'v2'

    -- 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.

    DECLARE @sendStream int
    -- Use "Chilkat_9_5_0.Stream" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Stream', @sendStream OUT

    -- Create a background thread task to upload from the stream
    -- The name of the Azure storage container is "test".
    -- After the background task is started and running in a background thread,
    -- the foreground thread will write 100 text lines of "this is a test\r\n" to the
    -- stream.
    DECLARE @uploadTask int
    EXEC sp_OAMethod @rest, 'SendReqStreamBodyAsync', @uploadTask OUT, 'PUT', '/test/thisIsATest.txt', @sendStream

    -- Start the task. 
    EXEC sp_OAMethod @uploadTask, 'Run', @success OUT

    -- The application can write to the stream, and close the stream
    -- when finished.  Whatever is written to the stream uploaded to the remote file.
    DECLARE @i int

    SELECT @i = 1
    WHILE @i <= 100
      BEGIN
        EXEC sp_OAMethod @sendStream, 'WriteString', @success OUT, 'This is a test' + CHAR(13) + CHAR(10)
        IF @success <> 1
          BEGIN
            EXEC sp_OAMethod @uploadTask, 'Cancel', @success OUT
            EXEC @hr = sp_OADestroy @uploadTask


            PRINT 'Failed to write to sendStream.'
            EXEC @hr = sp_OADestroy @rest
            EXEC @hr = sp_OADestroy @azAuth
            EXEC @hr = sp_OADestroy @sendStream
            RETURN
          END
        SELECT @i = @i + 1
      END

    -- Close the stream to indicate no more data will be sent.
    EXEC sp_OAMethod @sendStream, 'WriteClose', @success OUT

    -- Make sure the uploadTask has finished.
    -- It is likely that task is already finished..
    -- Wait a max of 5 seconds..
    EXEC sp_OAMethod @uploadTask, 'Wait', @success OUT, 5000

    -- OK.. we've sent the file, now we need to get the response..

    -- Read the response header.
    DECLARE @responseStatusCode int
    EXEC sp_OAMethod @rest, 'ReadResponseHeader', @responseStatusCode OUT
    IF @responseStatusCode < 0
      BEGIN
        -- We were unable to receive the response header.
        EXEC sp_OAGetProperty @rest, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @rest
        EXEC @hr = sp_OADestroy @azAuth
        EXEC @hr = sp_OADestroy @sendStream
        RETURN
      END

    -- 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 @responseStatusCode = 201
      BEGIN

        PRINT 'File uploaded.'
      END
    ELSE
      BEGIN
        -- It failed, so try reading the response body.  If no response body is coming,
        -- then Chilkat will know and just return an empty string.
        DECLARE @responseBodyStr nvarchar(4000)
        EXEC sp_OAMethod @rest, 'ReadRespBodyString', @responseBodyStr OUT
        EXEC sp_OAGetProperty @rest, 'LastMethodSuccess', @iTmp0 OUT
        IF @iTmp0 = 1
          BEGIN

            PRINT 'response body (if any): ' + @responseBodyStr
          END

        -- Examine the request/response to see what happened.

        EXEC sp_OAGetProperty @rest, 'ResponseStatusCode', @iTmp0 OUT
        PRINT 'response status code = ' + @iTmp0

        EXEC sp_OAGetProperty @rest, 'ResponseStatusText', @sTmp0 OUT
        PRINT 'response status text = ' + @sTmp0

        EXEC sp_OAGetProperty @rest, 'ResponseHeader', @sTmp0 OUT
        PRINT 'response header: ' + @sTmp0

        PRINT '---'

        EXEC sp_OAGetProperty @rest, 'LastRequestStartLine', @sTmp0 OUT
        PRINT 'LastRequestStartLine: ' + @sTmp0

        EXEC sp_OAGetProperty @rest, 'LastRequestHeader', @sTmp0 OUT
        PRINT 'LastRequestHeader: ' + @sTmp0
      END

    EXEC @hr = sp_OADestroy @rest
    EXEC @hr = sp_OADestroy @azAuth
    EXEC @hr = sp_OADestroy @sendStream


END
GO