VB.NET

REST Asynchronous Streaming Upload File

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Demonstrates how to asynchronous streaming upload a file to cloud storage. This particular example demonstrates an upload to the Azure Cloud Storage service. The same concepts apply to S3, Google Cloud, and Google Drive. 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 Azure Storage Blob Service
Dim bTls As Boolean = True
Dim port As Integer = 443
Dim bAutoReconnect As Boolean = True
' In this example, the storage account name is "chilkat".
success = rest.Connect("chilkat.blob.core.windows.net",port,bTls,bAutoReconnect)
If (success <> True) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


' Provide Azure Cloud credentials for the REST call.
Dim azAuth As New Chilkat.AuthAzureStorage
azAuth.AccessKey = "AZURE_ACCESS_KEY"
' The account name used here should match the 1st part of the domain passed in the call to Connect (above).
azAuth.Account = "chilkat"
azAuth.Scheme = "SharedKey"
azAuth.Service = "Blob"
' This causes the "x-ms-version: 2021-08-06" header to be automatically added.
azAuth.XMsVersion = "2021-08-06"
success = rest.SetAuthAzureStorage(azAuth)

' Set some request headers.
success = rest.AddHeader("x-ms-blob-content-disposition","attachment; filename=""thisIsATest.txt""")
success = rest.AddHeader("x-ms-blob-type","BlockBlob")
success = rest.AddHeader("x-ms-meta-m1","v1")
success = rest.AddHeader("x-ms-meta-m2","v2")

' Note: The application does not need to explicitly set the following
' headers: x-ms-date, Authorization, and Content-Length.  These headers
' are automatically set by Chilkat.

Dim sendStream As New Chilkat.Stream

' Define the source data for the stream to be a file.
sendStream.SourceFile = "qa_data/hamlet.xml"

' Create a background thread task to upload from the stream
' The name of the Azure storage container is "test".
Dim task As Chilkat.Task = rest.FullRequestStreamAsync("PUT","/test/thisIsATest.txt",sendStream)

' Start the task. 
success = task.Run()

' In this example, we'll simply sleep and periodically
' check to see if the REST upload if finished.
Dim curPctDone As Integer = 0
While task.Finished <> True
    task.SleepMs(100)
End While

' Check to see if the call to FullRequestStream in the background thread pool succeeded.
If (task.TaskSuccess <> True) Then
    ' Show what would've been the LastErrorText had FullRequestStream been called synchronously
    Debug.WriteLine(task.ResultErrorText)

    Exit Sub
End If


Dim responseStatusCode As Integer = rest.ResponseStatusCode

' When successful, the Azure Storage service will respond with a 201 response code,
' with an empty body.  Therefore, in the success condition, the responseStr is empty.
If (responseStatusCode = 201) Then
    Debug.WriteLine("File uploaded.")
Else
    ' It failed, so examine the response body, if one was returned:
    ' Given that FullRequestStream returns a string, the return value is obtained via GetResultString.
    Dim responseBodyStr As String = task.GetResultString()
    Debug.WriteLine("response body (if any): " & responseBodyStr)

    ' Examine the request/response to see what happened.
    Debug.WriteLine("response status code = " & rest.ResponseStatusCode)
    Debug.WriteLine("response status text = " & rest.ResponseStatusText)
    Debug.WriteLine("response header: " & rest.ResponseHeader)
    Debug.WriteLine("---")
    Debug.WriteLine("LastRequestStartLine: " & rest.LastRequestStartLine)
    Debug.WriteLine("LastRequestHeader: " & rest.LastRequestHeader)
End If