VB.NET

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.) VB.NET

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 New Chilkat.Rest

' Connect to the Amazon AWS REST server.
Dim bTls As Boolean = True
Dim port As Integer = 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 New Chilkat.AuthAws
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
    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 bodyStream As New Chilkat.Stream

    ' 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
        Debug.WriteLine(rest.LastErrorText)
        Exit Sub
    End If


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

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

End If