Read the REST Response Body in Chunks

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Demonstrates Rest.ReadRespChunkBd, which reads the response body one chunk at a time, appending each chunk to a BinData. A return value of 0 signals the body is complete, while -1 indicates a read failure.

--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @iTmp0 int
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    DECLARE @rest int
    EXEC @hr = sp_OACreate 'Chilkat.Rest', @rest OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    DECLARE @bTls int
    SELECT @bTls = 1
    DECLARE @bAutoReconnect int
    SELECT @bAutoReconnect = 1
    EXEC sp_OAMethod @rest, 'Connect', @success OUT, 'example.com', 443, @bTls, @bAutoReconnect
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @rest, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @rest
        RETURN
      END

    EXEC sp_OAMethod @rest, 'SendReqNoBody', @success OUT, 'GET', '/api/largefile'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @rest, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @rest
        RETURN
      END

    DECLARE @statusCode int
    EXEC sp_OAMethod @rest, 'ReadResponseHeader', @statusCode OUT
    IF @statusCode < 0
      BEGIN
        EXEC sp_OAGetProperty @rest, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @rest
        RETURN
      END

    --  Check for the expected success status code.  If the response is not 200, the body is likely
    --  error text formatted as JSON, XML, or HTML rather than the expected content.  In that case read
    --  the body as text, report it, and return.
    IF @statusCode <> 200
      BEGIN
        DECLARE @sbError int
        EXEC @hr = sp_OACreate 'Chilkat.StringBuilder', @sbError OUT

        EXEC sp_OAMethod @rest, 'ReadRespSb', @success OUT, @sbError
        IF @success = 0
          BEGIN
            EXEC sp_OAGetProperty @rest, 'LastErrorText', @sTmp0 OUT
            PRINT @sTmp0
            EXEC @hr = sp_OADestroy @rest
            EXEC @hr = sp_OADestroy @sbError
            RETURN
          END

        PRINT 'Request failed with status code ' + @statusCode
        EXEC sp_OAMethod @sbError, 'GetAsString', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @rest
        EXEC @hr = sp_OADestroy @sbError
        RETURN
      END

    --  The status code is 200.  Read the response body in chunks, appending each chunk to the BinData.
    --  Each call waits until at least the requested number of bytes is available, unless the response
    --  ends first.  A return value of 0 means the final bytes were returned and the body is complete;
    --  -1 indicates a read failure.
    DECLARE @bdBody int
    EXEC @hr = sp_OACreate 'Chilkat.BinData', @bdBody OUT

    DECLARE @chunkResult int
    EXEC sp_OAMethod @rest, 'ReadRespChunkBd', @chunkResult OUT, 8192, @bdBody
    WHILE @chunkResult > 0
      BEGIN
        EXEC sp_OAMethod @rest, 'ReadRespChunkBd', @chunkResult OUT, 8192, @bdBody
      END
    IF @chunkResult < 0
      BEGIN
        EXEC sp_OAGetProperty @rest, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @rest
        EXEC @hr = sp_OADestroy @sbError
        EXEC @hr = sp_OADestroy @bdBody
        RETURN
      END

    EXEC sp_OAGetProperty @bdBody, 'NumBytes', @iTmp0 OUT

    PRINT 'Received ' + @iTmp0 + ' bytes.'

    EXEC @hr = sp_OADestroy @rest
    EXEC @hr = sp_OADestroy @sbError
    EXEC @hr = sp_OADestroy @bdBody


END
GO