(SQL Server) Understanding ZIP Entry Types and the ZIP Object Lifecycle

See more Zip Examples

This example demonstrates how the Chilkat.Zip object manages entries before and after a ZIP archive is written.

The example shows:

• How file references are added from the local filesystem using AppendFilesEx
• How in-memory entries are added using AddString
• How ZIP entry types change as the ZIP archive progresses from an in-memory staging object to an actual written .zip file
• How additional entries can continue to be added even after the ZIP archive has already been written

The example also demonstrates the meaning of the different ZipEntry.EntryType values:

• 1 — File references in the local filesystem that have not yet been processed
• 2 — In-memory data entries
• 0 — Entries mapped to an existing open ZIP archive

This example is useful for understanding how the Chilkat.Zip class internally stages entries prior to writing the final ZIP archive.

Note: This example requires Chilkat v11.0.0 or greater.

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)
    DECLARE @success int
    SELECT @success = 0

    SELECT @success = 0

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

    DECLARE @zipPath nvarchar(4000)
    SELECT @zipPath = 'c:/temp/out.zip'

    -- Start a new Zip object and set the output path.
    -- This does not create the .zip file yet.  It only initializes the Zip object
    -- and records the filename to be used later when WriteZip is called.
    EXEC sp_OAMethod @zip, 'NewZip', @success OUT, @zipPath

    -- Add references to files in the local filesystem.
    -- AppendFilesEx does not read, compress, or store the file contents at this point.
    -- It only adds file references to the Zip object.  The referenced files are
    -- read and compressed later, when WriteZip is called.
    DECLARE @recurse int
    SELECT @recurse = 1
    DECLARE @saveExtraPath int
    SELECT @saveExtraPath = 0
    DECLARE @archiveOnly int
    SELECT @archiveOnly = 0
    DECLARE @includeHidden int
    SELECT @includeHidden = 1
    DECLARE @includeSystem int
    SELECT @includeSystem = 0
    EXEC sp_OAMethod @zip, 'AppendFilesEx', @success OUT, 'c:/temp/files_to_zip', @recurse, @saveExtraPath, @archiveOnly, @includeHidden, @includeSystem
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @zip, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @zip
        RETURN
      END

    -- We can inspect the entries that have been added to the Zip object.
    -- At this stage, the entries are still references to files in the local filesystem.
    DECLARE @entry int
    EXEC @hr = sp_OACreate 'Chilkat.ZipEntry', @entry OUT

    DECLARE @count int
    EXEC sp_OAGetProperty @zip, 'NumEntries', @count OUT
    DECLARE @i int
    SELECT @i = 0
    WHILE @i < @count
      BEGIN
        EXEC sp_OAMethod @zip, 'EntryAt', @success OUT, @i, @entry
        EXEC sp_OAGetProperty @entry, 'FileName', @sTmp0 OUT

        EXEC sp_OAGetProperty @entry, 'EntryType', @iTmp0 OUT
        PRINT @sTmp0 + ' entryType = ' + @iTmp0
        SELECT @i = @i + 1
      END

    PRINT '----'

    -- Sample output for the above loop:
    -- 
    -- hamlet.xml entryType = 1
    -- hello.pdf entryType = 1
    -- ...
    -- ...
    -- 
    -- entryType = 1 means "File Entry".
    -- A File Entry is a reference to a file in the local filesystem.
    -- The file data has not yet been read into the Zip object.
    -- 
    -- Possible entryType values:
    -- 
    -- 0 - Mapped Entry:
    --     An entry that already exists in an open .zip file.
    -- 
    -- 1 - File Entry:
    --     A file in the local filesystem that has been referenced, but not yet
    --     read or compressed.  These entries are added by methods such as
    --     AppendFiles, AppendFilesEx, and AddFile.
    -- 
    -- 2 - Data Entry:
    --     An entry containing uncompressed data already held in memory.
    --     These entries are added by methods such as AddData, AddString,
    --     AddSb, AddBd, and AddEncoded.
    -- 
    -- 3 - Null Entry:
    --     An entry that no longer exists in the .zip.
    -- 
    -- 4 - New Directory Entry:
    --     A directory entry added by calling AddEmpty.

    -- Additional entries can still be added before the .zip is written.
    -- This entry is created from an in-memory string, so it is a Data Entry
    -- rather than a File Entry.
    EXEC sp_OAMethod @zip, 'AddString', @success OUT, 'helloWorld.txt', 'Hello World', 'utf-8'

    -- Inspect the Zip object again before writing.
    -- The file references are still entryType = 1.
    -- The in-memory string entry is entryType = 2.
    EXEC sp_OAGetProperty @zip, 'NumEntries', @count OUT
    SELECT @i = 0
    WHILE @i < @count
      BEGIN
        EXEC sp_OAMethod @zip, 'EntryAt', @success OUT, @i, @entry
        EXEC sp_OAGetProperty @entry, 'FileName', @sTmp0 OUT

        EXEC sp_OAGetProperty @entry, 'EntryType', @iTmp0 OUT
        PRINT @sTmp0 + ' entryType = ' + @iTmp0
        SELECT @i = @i + 1
      END

    PRINT '----'

    -- Sample output:
    -- 
    -- hamlet.xml entryType = 1
    -- hello.pdf entryType = 1
    -- ...
    -- ...
    -- helloWorld.txt entryType = 2
    -- 
    -- helloWorld.txt has entryType = 2 because its contents came from memory.
    -- It is not a reference to a file in the local filesystem.

    -- ----------------------------------------------------------------------------
    -- Write the Zip object to the .zip file.
    -- 
    -- During this call, Chilkat reads the referenced files from the local filesystem,
    -- compresses the data as needed, and writes the final .zip archive.
    EXEC sp_OASetProperty @zip, 'FileName', @zipPath
    EXEC sp_OAMethod @zip, 'WriteZip', @success OUT
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @zip, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @zip
        EXEC @hr = sp_OADestroy @entry
        RETURN
      END

    -- After WriteZip returns successfully, the .zip file is written and remains
    -- open in the Zip object.  The entries now correspond to entries in the
    -- currently open .zip archive.
    EXEC sp_OAGetProperty @zip, 'NumEntries', @count OUT
    SELECT @i = 0
    WHILE @i < @count
      BEGIN
        EXEC sp_OAMethod @zip, 'EntryAt', @success OUT, @i, @entry
        EXEC sp_OAGetProperty @entry, 'FileName', @sTmp0 OUT

        EXEC sp_OAGetProperty @entry, 'EntryType', @iTmp0 OUT
        PRINT @sTmp0 + ' entryType = ' + @iTmp0
        SELECT @i = @i + 1
      END

    PRINT '----'

    -- Sample output:
    -- 
    -- hamlet.xml entryType = 0
    -- hello.pdf entryType = 0
    -- ...
    -- ...
    -- helloWorld.txt entryType = 0
    -- 
    -- entryType = 0 means "Mapped Entry".
    -- A Mapped Entry is an entry that exists in an open .zip file.

    -- ----------------------------------------------------------------------------
    -- The .zip remains open after WriteZip, so additional entries can still be added.
    -- 
    -- This adds another in-memory string entry to the currently open Zip object.
    EXEC sp_OAMethod @zip, 'AddString', @success OUT, 'helloWorld2.txt', 'Hello World 2', 'utf-8'

    -- Write the .zip again to include the newly added entry.
    EXEC sp_OAMethod @zip, 'WriteZip', @success OUT
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @zip, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @zip
        EXEC @hr = sp_OADestroy @entry
        RETURN
      END

    -- Inspect the entries one final time.
    -- After the second WriteZip, the new entry is also mapped to the open .zip file.
    EXEC sp_OAGetProperty @zip, 'NumEntries', @count OUT
    SELECT @i = 0
    WHILE @i < @count
      BEGIN
        EXEC sp_OAMethod @zip, 'EntryAt', @success OUT, @i, @entry
        EXEC sp_OAGetProperty @entry, 'FileName', @sTmp0 OUT

        EXEC sp_OAGetProperty @entry, 'EntryType', @iTmp0 OUT
        PRINT @sTmp0 + ' entryType = ' + @iTmp0
        SELECT @i = @i + 1
      END

    PRINT '----'

    -- Sample output:
    -- 
    -- hamlet.xml entryType = 0
    -- hello.pdf entryType = 0
    -- ...
    -- ...
    -- helloWorld.txt entryType = 0
    -- helloWorld2.txt entryType = 0

    -- Close the open .zip archive and clear the Zip object.
    EXEC sp_OAMethod @zip, 'CloseZip', NULL


    PRINT 'Success'

    EXEC @hr = sp_OADestroy @zip
    EXEC @hr = sp_OADestroy @entry


END
GO