(SQL Server) Unzip One File to a Stream

Demonstrates how to unzip a particular file contained within a .zip archive to a Chilkat stream.

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
    DECLARE @sTmp0 nvarchar(4000)
    -- This example requires the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    DECLARE @zip int
    EXEC @hr = sp_OACreate 'Chilkat_9_5_0.Zip', @zip OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- First open a .zip.
    DECLARE @success int
    EXEC sp_OAMethod @zip, 'OpenZip', @success OUT, 'qa_data/hamlet.zip'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @zip, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @zip
        RETURN
      END

    -- Find the entry to be unzipped to a stream..
    DECLARE @entry int
    EXEC sp_OAMethod @zip, 'FirstMatchingEntry', @entry OUT, '*hamlet.xml'
    EXEC sp_OAGetProperty @zip, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @zip, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @zip
        RETURN
      END

    -- There are three ways we can unzip (inflate) to a stream.
    -- 
    -- 1) Set a sink file on the stream object and call UnzipToStream synchronously.
    --    This unzips to the stream's sink (which is to simply unzip to a file in the filesystem).
    -- 
    -- 2) Create a stream object and call UnzipToStreamAsync.  This starts the unzip in a background
    --    thread (after Task.Run is called).  Your application can then read the unzipped (inflated) file
    --    directly from the stream.
    -- 
    -- 3) (not shown in this example) Unzip to a stream object that is the source of something else.
    --    

    -- ----------------------------------------------------------------
    -- Case 1: Unzip to a file by setting the sink of streamA to a file.
    DECLARE @streamA int
    EXEC @hr = sp_OACreate 'Chilkat_9_5_0.Stream', @streamA OUT

    EXEC sp_OASetProperty @streamA, 'SinkFile', 'qa_output/hamletA.xml'

    EXEC sp_OAMethod @entry, 'UnzipToStream', @success OUT, @streamA
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @entry, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @entry

        EXEC @hr = sp_OADestroy @zip
        EXEC @hr = sp_OADestroy @streamA
        RETURN
      END

    -- Close the stream to close the output file.
    EXEC sp_OAMethod @streamA, 'WriteClose', @success OUT

    -- ----------------------------------------------------------------
    -- Case 2a: Uzip to a stream asynchronously. 
    DECLARE @streamB int
    EXEC @hr = sp_OACreate 'Chilkat_9_5_0.Stream', @streamB OUT

    DECLARE @unzipTask int
    EXEC sp_OAMethod @entry, 'UnzipToStreamAsync', @unzipTask OUT, @streamB
    EXEC sp_OAGetProperty @entry, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @entry, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @entry

        EXEC @hr = sp_OADestroy @zip
        EXEC @hr = sp_OADestroy @streamA
        EXEC @hr = sp_OADestroy @streamB
        RETURN
      END

    -- Start the background unzip thread.
    EXEC sp_OAMethod @unzipTask, 'Run', @success OUT

    -- Read the stream.  (this is reading the unzipped file data)
    DECLARE @sb int
    EXEC @hr = sp_OACreate 'Chilkat_9_5_0.StringBuilder', @sb OUT

    EXEC sp_OAGetProperty @streamB, 'EndOfStream', @iTmp0 OUT
    WHILE @iTmp0 <> 1
      BEGIN
        -- Each call to ReadSb appends to the contents of sb.
        EXEC sp_OAMethod @streamB, 'ReadSb', @success OUT, @sb
      END
    EXEC sp_OAMethod @sb, 'WriteFile', @success OUT, 'qa_output/hamletB.xml', 'utf-8', 0

    EXEC @hr = sp_OADestroy @unzipTask


    PRINT 'Success.'

    -- ----------------------------------------------------------------
    -- Case 2b: Uzip to a stream asynchronously and emit output while reading. 
    DECLARE @streamC int
    EXEC @hr = sp_OACreate 'Chilkat_9_5_0.Stream', @streamC OUT

    EXEC sp_OAMethod @entry, 'UnzipToStreamAsync', @unzipTask OUT, @streamC
    EXEC sp_OAGetProperty @entry, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @entry, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @entry

        EXEC @hr = sp_OADestroy @zip
        EXEC @hr = sp_OADestroy @streamA
        EXEC @hr = sp_OADestroy @streamB
        EXEC @hr = sp_OADestroy @sb
        EXEC @hr = sp_OADestroy @streamC
        RETURN
      END

    EXEC sp_OAMethod @unzipTask, 'Run', @success OUT

    EXEC sp_OAGetProperty @streamC, 'EndOfStream', @iTmp0 OUT
    WHILE @iTmp0 <> 1
      BEGIN
        DECLARE @s nvarchar(4000)
        EXEC sp_OAMethod @streamC, 'ReadString', @s OUT

        PRINT @s
      END

    EXEC @hr = sp_OADestroy @entry

    EXEC @hr = sp_OADestroy @unzipTask


    PRINT 'Success.'

    EXEC @hr = sp_OADestroy @zip
    EXEC @hr = sp_OADestroy @streamA
    EXEC @hr = sp_OADestroy @streamB
    EXEC @hr = sp_OADestroy @sb
    EXEC @hr = sp_OADestroy @streamC


END
GO