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(SQL Server) Compress and Encrypt a Large File (Low and Constant Memory Footprint)See more Compression ExamplesDemonstrates how to compress and encrypt a large file such that the memory footprint remains low and constant. Note: This example requires Chilkat v9.5.0.99 or greater.
-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls. -- CREATE PROCEDURE ChilkatSample AS BEGIN DECLARE @hr int -- Important: Do not use nvarchar(max). See the warning about using nvarchar(max). DECLARE @sTmp0 nvarchar(4000) -- This example assumes the Chilkat API to have been previously unlocked. -- See Global Unlock Sample for sample code. DECLARE @compress int EXEC @hr = sp_OACreate 'Chilkat_9_5_0.Compression', @compress OUT IF @hr <> 0 BEGIN PRINT 'Failed to create ActiveX component' RETURN END EXEC sp_OASetProperty @compress, 'Algorithm', 'deflate' DECLARE @success int -- Set encryption params. -- The possible values are the same as for the corresponding properties in the Chilkat Crypt2 class/object. -- The encoded IV and Key must be specified as hex. DECLARE @json int EXEC @hr = sp_OACreate 'Chilkat_9_5_0.JsonObject', @json OUT EXEC sp_OAMethod @json, 'UpdateString', @success OUT, 'cryptAlgorithm', 'aes' EXEC sp_OAMethod @json, 'UpdateString', @success OUT, 'cipherMode', 'cbc' EXEC sp_OAMethod @json, 'UpdateInt', @success OUT, 'keyLength', 128 EXEC sp_OAMethod @json, 'UpdateInt', @success OUT, 'paddingScheme', 0 EXEC sp_OAMethod @json, 'UpdateString', @success OUT, 'encodedIV', '000102030405060708090A0B0C0D0E0F' EXEC sp_OAMethod @json, 'UpdateString', @success OUT, 'encodedKey', '000102030405060708090A0B0C0D0E0F' -- Do file-to-file compression+encryption in a single call. DECLARE @inPath nvarchar(4000) SELECT @inPath = 'qa_data/largeFile.dat' DECLARE @outPath nvarchar(4000) SELECT @outPath = 'c:/temp/qa_output/compressed_encrypted.dat' EXEC sp_OAMethod @compress, 'CompressEncryptFile', @success OUT, @json, @inPath, @outPath IF @success = 0 BEGIN EXEC sp_OAGetProperty @compress, 'LastErrorText', @sTmp0 OUT PRINT @sTmp0 EXEC @hr = sp_OADestroy @compress EXEC @hr = sp_OADestroy @json RETURN END -- We can do file-to-file decrypt/decompress like this: DECLARE @inPath2 nvarchar(4000) SELECT @inPath2 = @outPath DECLARE @outPath2 nvarchar(4000) SELECT @outPath2 = 'c:/temp/qa_output/restored.dat' EXEC sp_OAMethod @compress, 'DecryptDecompressFile', @success OUT, @json, @inPath2, @outPath2 IF @success = 0 BEGIN EXEC sp_OAGetProperty @compress, 'LastErrorText', @sTmp0 OUT PRINT @sTmp0 EXEC @hr = sp_OADestroy @compress EXEC @hr = sp_OADestroy @json RETURN END -- Note: The above decrypt + decompress is the equivalent of doing the same in these two steps: DECLARE @crypt int EXEC @hr = sp_OACreate 'Chilkat_9_5_0.Crypt2', @crypt OUT EXEC sp_OASetProperty @crypt, 'CryptAlgorithm', 'aes' EXEC sp_OASetProperty @crypt, 'CipherMode', 'cbc' EXEC sp_OASetProperty @crypt, 'KeyLength', 128 EXEC sp_OASetProperty @crypt, 'PaddingScheme', 0 EXEC sp_OAMethod @crypt, 'SetEncodedIV', NULL, '000102030405060708090A0B0C0D0E0F', 'hex' EXEC sp_OAMethod @crypt, 'SetEncodedKey', NULL, '000102030405060708090A0B0C0D0E0F', 'hex' DECLARE @decryptedPath nvarchar(4000) SELECT @decryptedPath = 'c:/temp/qa_output/decrypted.dat' EXEC sp_OAMethod @crypt, 'CkDecryptFile', @success OUT, @inPath2, @decryptedPath IF @success = 0 BEGIN EXEC sp_OAGetProperty @crypt, 'LastErrorText', @sTmp0 OUT PRINT @sTmp0 EXEC @hr = sp_OADestroy @compress EXEC @hr = sp_OADestroy @json EXEC @hr = sp_OADestroy @crypt RETURN END DECLARE @outPath3 nvarchar(4000) SELECT @outPath3 = 'c:/temp/qa_output/restored_in_two_steps.dat' EXEC sp_OAMethod @compress, 'DecompressFile', @success OUT, @decryptedPath, @outPath3 IF @success = 0 BEGIN EXEC sp_OAGetProperty @compress, 'LastErrorText', @sTmp0 OUT PRINT @sTmp0 EXEC @hr = sp_OADestroy @compress EXEC @hr = sp_OADestroy @json EXEC @hr = sp_OADestroy @crypt RETURN END PRINT 'Success.' EXEC @hr = sp_OADestroy @compress EXEC @hr = sp_OADestroy @json EXEC @hr = sp_OADestroy @crypt END GO |
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