B4X

(using AWS Signature Version 2) Streaming Download to File

See more Amazon S3 (new) Examples

The main purpose of this example is to demonstrate how to use the older Signature Version 2 authentication w/ S3. It uses V2 authentication to download a file. B4X

Dim success As Boolean = False

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

Dim rest As ChilkatRest
rest.Initialize("rest")

'  Connect to the Amazon AWS REST server.
Dim bTls As Boolean = True
Dim port As Int = 443
Dim bAutoReconnect As Boolean = True
'  The file is located in the bucket named "chilkat100", which becomes part of the domain:
success = rest.Connect("chilkat100.s3.amazonaws.com", port, bTls, bAutoReconnect)

'  Provide AWS credentials for the REST call.
Dim authAws As ChilkatAuthAws
authAws.Initialize
authAws.AccessKey = "AWS_ACCESS_KEY"
authAws.SecretKey = "AWS_SECRET_KEY"
authAws.ServiceName = "s3"

'  For AWS Signature Version 2, the following two properties need to be set:
authAws.SignatureVersion = 2
'  See http://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAuthentication.html#ConstructingTheCanonicalizedResourceElement
authAws.CanonicalizedResourceV2 = "/chilkat100/starfish.jpg"

success = rest.SetAuthAws(authAws)

'  Send the request to download the JPG.
success = rest.SendReqNoBody("GET", "/starfish.jpg")
If success <> True Then
    Log(rest.LastErrorText)
    Return
End If


'  Read the response header.
Dim responseStatusCode As Int = rest.ReadResponseHeader
If responseStatusCode < 0 Then
    Log(rest.LastErrorText)
    Return
End If


Log("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 bodyStream As ChilkatStream
    bodyStream.Initialize("bodyStream")

    '  The stream's sink will be a file.
    bodyStream.SinkFile = "qa_output/starfish.jpg"

    '  Read the response body to the stream.  Given that we've
    '  set the stream's sink to a file, it will stream directly
    '  to the file.
    success = rest.ReadRespBodyStream(bodyStream, True)
    If success <> True Then
        Log(rest.LastErrorText)
        Return
    End If


    Log("Successfully received the JPG file.")

Else
    Dim errResponse As String = rest.ReadRespBodyString
    If rest.LastMethodSuccess <> True Then
        Log(rest.LastErrorText)
    Else
        Log(errResponse)
    End If

End If