SQL Server

Append Text Data to an Existing ZIP Entry Using ZipEntry.AppendString

See more Zip Examples

This example demonstrates how to use the ZipEntry.AppendString method to append text data to an existing ZIP entry.

The example opens an existing ZIP archive, locates a text file entry, and appends additional text to the end of the file contents.

An important concept demonstrated by this example is that appending data to a ZIP entry transforms the entry into an in-memory Data Entry (EntryType = 2).

For example:

• If the entry is a mapped entry from an opened ZIP archive (EntryType = 0), the compressed entry is first inflated into memory.
• If the entry is a referenced filesystem file (EntryType = 1), the file contents are first loaded into memory.

The new text is then appended to the uncompressed in-memory data, and the entry becomes a Data Entry.

After the ZIP archive is rewritten, the modified entry again becomes a mapped entry stored within the ZIP archive.

SQL Server

-- 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

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

    -- ------------------------------------------------------------
    -- Open an existing ZIP archive.
    EXEC sp_OAMethod @zip, 'OpenZip', @success OUT, 'c:/temp/notes.zip'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @zip, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @zip
        RETURN
      END

    -- Locate a text file entry within the ZIP archive.
    DECLARE @entry int
    EXEC @hr = sp_OACreate 'Chilkat.ZipEntry', @entry OUT

    EXEC sp_OAMethod @zip, 'EntryOf', @success OUT, 'notes/readme.txt', @entry

    IF @success <> 0
      BEGIN

        -- --------------------------------------------------------
        -- At this point, the entry is a mapped entry because it
        -- originates from an opened ZIP archive.
        -- 
        --     EntryType = 0
        -- 

        EXEC sp_OAGetProperty @entry, 'EntryType', @iTmp0 OUT
        PRINT 'Initial EntryType = ' + @iTmp0

        -- Append additional text to the ZIP entry.
        -- 
        -- The existing compressed ZIP entry is first inflated
        -- into memory. The new text is then appended.
        -- 
        -- After AppendString is called, the entry becomes
        -- an in-memory Data Entry:
        -- 
        --     EntryType = 2
        -- 
        EXEC sp_OAMethod @entry, 'AppendString', @success OUT, CHAR(13) + CHAR(10) + 'Additional notes added later.', 'utf-8'

        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


        EXEC sp_OAGetProperty @entry, 'EntryType', @iTmp0 OUT
        PRINT 'EntryType after AppendString = ' + @iTmp0

        -- --------------------------------------------------------
        -- Write the modified ZIP archive to a different file.
        -- 
        -- Changing zip.FileName causes the ZIP archive to be
        -- written to a new output file rather than overwriting
        -- the original ZIP archive.
        -- 
        EXEC sp_OASetProperty @zip, 'FileName', 'qa_output/updatedExample.zip'

        -- Rewrite the ZIP archive.
        -- 
        -- The modified in-memory entry is compressed and written
        -- into the new ZIP archive.
        -- 
        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 rewriting the ZIP archive, the entry again becomes
        -- a mapped entry:
        -- 
        --     EntryType = 0
        -- 

        EXEC sp_OAGetProperty @entry, 'EntryType', @iTmp0 OUT
        PRINT 'EntryType after WriteZip = ' + @iTmp0
      END

    EXEC sp_OAMethod @zip, 'CloseZip', NULL


    PRINT 'ZIP entry updated successfully.'

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


END
GO