(Xojo Plugin) REST Read Response with Stream API

Demonstrates how to make a REST call that returns a binary body, and to receive the body through a stream API.

Chilkat Xojo Plugin Download Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

// 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
bTls = True
Dim port As Int32
port = 443
Dim bAutoReconnect As Boolean
bAutoReconnect = True
Dim success As Boolean
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
    System.DebugLog(rest.LastErrorText)
    Return
End If

// Read the response header.
Dim responseStatusCode As Int32
responseStatusCode = rest.ReadResponseHeader()
If (responseStatusCode < 0) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

System.DebugLog("Response status code = " + Str(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
    errResponse = rest.ReadRespBodyString()
    If (rest.LastMethodSuccess <> True) Then
        System.DebugLog(rest.LastErrorText)
    Else
        System.DebugLog(errResponse)
    End If

    Return
End If

Dim bodyStream As New Chilkat.Stream
// Set a 10 second read timeout for the stream. 
// (Give up if no data arrives within 10 seconds after calling a read method.)
bodyStream.ReadTimeoutMs = 10000

// Create a background thread task to read the response body (which feeds
// it to the bodyStream object.)
Dim readResponseBodyTask As Chilkat.Task
readResponseBodyTask = rest.ReadRespBodyStreamAsync(bodyStream,True)

// Start the task. 
success = readResponseBodyTask.Run()

// The application can now read the bodyStream...
While (bodyStream.EndOfStream <> True)

    // Read the next chunk of bytes (whatever is immediately available,
    // or wait for more data (up to 10 seconds because we set the stream's ReadTimeoutMs property)
    Dim nextChunk As MemoryBlock
    nextChunk = bodyStream.ReadBytes()
    If (bodyStream.LastMethodSuccess <> True) Then
        System.DebugLog("Failed to receive more response data.")
        // Make sure the background task is aborted/cancelled.
        success = readResponseBodyTask.Cancel()

        Return
    End If

    // OK.. the app has the next chunk of the body, and may do whatever it wishes with it...
Wend

System.DebugLog("Successfully received the entire response body.")