File Compression For Insert in DataBase

[Jean-Charles]

Language: VB.NET

Hello,

I'm looking to use CompressedStream solution without really understanding its use.

What I am trying to do:
1. compress file.
2. Insert the compressed file into my Database.
3. Retrieve compressed file to unzip it.
4. Read file.

How can I efficiently compress the file ?
Which method should I use ?
What type of variable should I deal with ? (String, Byte ()?)

Would you have a functional example in .net to help me ?

Thanks for your help

[Jean-Charles]

I have read this documentation:

https://docs.telerik.com/devtools/document-processing/libraries/radziplibrary/features/compress-stream

but it does not help me to understand

[Jean-Charles]

Pour les intéressés :)

It's better to work on bytes rather than text ...
So no streamreader & co ...

 

Public encryptionSettings As New DefaultEncryptionSettings()
Public PassKey As String = "MOTDEPASSEDELAMORTQUITUE"
Public result As Byte()

Public Function Compress(filebuffer As Byte()) As Byte()
    Using outputStream As New MemoryStream()
        Using inputStream As New MemoryStream(filebuffer)

            encryptionSettings.Password = PassKey

            Dim compressionSettings As New LzmaSettings()
            compressionSettings.DictionarySize = 26
            compressionSettings.FastBytes = 155
            compressionSettings.LiteralContextBits = 4
            compressionSettings.LiteralPositionBits = 1
            compressionSettings.MatchFinderType = LzmaMatchFinderType.BT4
            compressionSettings.PositionStateBits = 1

            Using compressedStream As New CompressedStream(outputStream, StreamOperationMode.Write, compressionSettings, Nothing, encryptionSettings)
                inputStream.CopyTo(compressedStream)
                compressedStream.Flush()
            End Using
        End Using
        result = outputStream.ToArray
    End Using
    Return result
End Function

Public Function UnCompress(filebuffer As Byte()) As Byte()
    Dim result As Byte()
    Using outputStream As New MemoryStream()
        Using inputStream As New MemoryStream(filebuffer)

            Dim encryptionSettings As New DefaultEncryptionSettings()
            encryptionSettings.Password = PassKey


            Using compressedStream As New CompressedStream(inputStream, StreamOperationMode.Read, New LzmaSettings(), Nothing, encryptionSettings)
                compressedStream.CopyTo(outputStream)
            End Using
        End Using
        result = outputStream.ToArray
    End Using

    Dim MyOutputStream As IO.MemoryStream
    MyOutputStream = New MemoryStream(result.ToArray)
    Form_reader.RadPdfViewer1.LoadDocument(MyOutputStream)
    Form_reader.Show()

    Return result
End Function

 

[Tanya]

Hi Jean-Charles,

I am happy to hear that you managed to implement the desired behavior.

Something additional I would like to mention is that you can create directly ZIP files if you prefer to. To achieve that, you can use the ZipFile class enabling you to easily add and extract files to/from a ZipArchive. VB.NET snippets are currently not available for the Telerik Document Processing documentation but you could use http://converter.telerik.com/ to convert the C# code.

Hope this is helpful.

Regards,
Tanya
Progress Telerik