(VB.NET UWP/WinRT) HTTP multipart/form-data Upload

Demonstrates how to upload files to an HTTP server using a multipart/form-data POST.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

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

Dim http As New Chilkat.Http

Dim req As New Chilkat.HttpRequest
req.HttpVerb = "POST"
req.ContentType = "multipart/form-data"
req.Path = "rcvFormDataUpload.aspx"

' Send an "Expect: 100-continue" header in the request.
' This causes the HTTP server to end a 100-continue response
' immediately after receiving the HTTP header.  The client
' (Chilkat) will receive this intermediate response, and if
' it's not an error response, it knows that the HTTP server will
' accept the data that is forthcoming.
' The alternative is to get an error response after trying to upload
' the entire contents of the files.
req.AddHeader("Expect","100-continue")

' Call AddFileForUpload2 for each file to be uploaded in the HTTP multipart/form-data POST
' To allow Chilkat to determine the content-type automatically based on file-extension,
' call AddFileForUpload instead.

' The 1st arg is the filename passed in the HTTP request.
' The 2nd arg is the path in the local filesytem.
' The file is not loaded into memory.  It is streamed directly from the file
' when the HTTP POST is sent.
Dim success As Boolean = req.AddFileForUpload2("starfish.jpg","c:/qa_data/starfish.jpg","image/jpg")
If (success <> True) Then
    Debug.WriteLine(req.LastErrorText)
    Exit Sub
End If


success = req.AddFileForUpload("something.pdf","c:/qa_data/something.pdf")
If (success <> True) Then
    Debug.WriteLine(req.LastErrorText)
    Exit Sub
End If


' Its also possible to add a file from a string:
success = req.AddStringForUpload("test.xml","test.xml","<abc>This is the test.xml content</abc>","utf-8")
' We'll assume success since no files are involved..


' This sends the HTTP request (with 3 files being uploaded) to
' http://www.mywebserver123abc.com/rcvFormDataUpload.aspx
Dim resp As Chilkat.HttpResponse
resp = Await http.SynchronousRequestAsync("www.mywebserver123abc.com",80,False,req)
If (http.LastMethodSuccess <> True) Then
    Debug.WriteLine(http.LastErrorText)
Else
    Debug.WriteLine("HTTP response status: " & resp.StatusCode)
    ' See the online reference documentation for 
    ' other information that can be obtained from the response object.

End If



' To send using SSL/TLS, do this instead.
' This sends to https://www.mywebserver123abc.com/rcvFormDataUpload.aspx
resp = Await http.SynchronousRequestAsync("www.mywebserver123abc.com",443,True,req)
If (http.LastMethodSuccess <> True) Then
    Debug.WriteLine(http.LastErrorText)
Else
    Debug.WriteLine("HTTP response status: " & resp.StatusCode)
    ' See the online reference documentation for 
    ' other information that can be obtained from the response object.

End If