B4X

REST Stream Response to File (Streaming Download) (Amazon S3)

See more Amazon S3 (new) Examples

Demonstrates how to stream the response body directly to a file. (The example shows how to stream a JPG from the Amazon S3 service.) 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
success = rest.Connect("s3.amazonaws.com", port, bTls, bAutoReconnect)

'  ----------------------------------------------------------------------------
'  Important: For buckets created in regions outside us-east-1,
'  there are three important changes that need to be made.
'  See Working with S3 Buckets in Non-us-east-1 Regions for the details.
'  ----------------------------------------------------------------------------

'  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"
success = rest.SetAuthAws(authAws)

'  Set the bucket name via the HOST header.
'  In this case, the bucket name is "chilkat100".
rest.Host = "chilkat100.s3.amazonaws.com"

'  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