(VB.NET) Streaming Decrypt HTTP Response

If the an encrypted file was previously uploaded, this example demonstrates how to download and decrypt in a streaming way.

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim rest As New Chilkat.Rest

Dim bTls As Boolean = True
Dim port As Integer = 443
Dim bAutoReconnect As Boolean = True
Dim success As Boolean = rest.Connect("chilkatdownload.com",port,bTls,bAutoReconnect)

' Send the request to download a file.
success = rest.SendReqNoBody("GET","/9.5.0.83/chilkat-9.5.0-python-3.8-x64.zip")
If (success <> True) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


' Read the response header.
Dim responseStatusCode As Integer = rest.ReadResponseHeader()
If (responseStatusCode < 0) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Response status code = " & responseStatusCode)

' We expect a 200 response status if the JPG data is coming.
' Otherwise, we'll get a string response body with an error message(or no response body).
If (responseStatusCode <> 200) Then
    Dim errResponse As String = rest.ReadRespBodyString()
    If (rest.LastMethodSuccess <> True) Then
        Debug.WriteLine(rest.LastErrorText)
    Else
        Debug.WriteLine(errResponse)
    End If

    Exit Sub
End If


' Create an object for decrypting.
' This example will use "none" for the encryption algorithm, which means it's just a pass-through.
' Typically you would set the decrypt properties, such as secret key, IV, key length, padding scheme, cipher mode..
Dim crypt As New Chilkat.Crypt2
crypt.CryptAlgorithm = "none"

' The following settings are ignored in this test because our CryptAlgorithm is "none".
' However, if you were truly decrypting, you might set CryptAlgorithm = "aes".
crypt.CipherMode = "cbc"
crypt.KeyLength = 128
crypt.SetEncodedKey("000102030405060708090A0B0C0D0E0F","hex")
crypt.SetEncodedIV("000102030405060708090A0B0C0D0E0F","hex")

Dim receiveStream As New Chilkat.Stream
' The decryptStream's source will be the receiveStream.
Dim decryptStream As New Chilkat.Stream

' The decrypt stream's sink will be a file.
decryptStream.SinkFile = "qa_output/chilkat-9.5.0-python-3.8-x64.zip"
decryptStream.SetSourceStream(receiveStream)

' Create and run a background async task to decrypt incoming data and write to a file.
Dim decryptStreamTask As Chilkat.Task = crypt.DecryptStreamAsync(decryptStream)
success = decryptStreamTask.Run()

success = rest.ReadRespBodyStream(receiveStream,True)
If (success <> True) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Successfully received the .zip file.")