(VB.NET UWP/WinRT) HTTPS multipart/form-data POST

Demonstrates how to send a multipart/form-data POST over HTTPS (using TLS).

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

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

' This example demonstrates how to send a multipart/form-data POST that
' looks like this:

' 	POST /cgi/XXX.pl HTTP/1.0
' 	Accept: text/html
' 	Connection: Keep-Alive
' 	User-Agent: XXX/8.0.15
' 	Content-type: multipart/form-data, boundary=XXXxyxy
' 	Content-Length: 682
' 
' 	--XXXxyxy
' 	content-disposition: form-data; name="UploadAgent"
' 
' 	InterfaceVersion1.5
' 	--XXXxyxy
' 	content-disposition: form-data; name="user"
' 
' 	userValue
' 	--XXXxyxy
' 	content-disposition: form-data; name="password"
' 
' 	passwordValue
' 	--XXXxyxy
' 	content-disposition: form-data; name="file"
' 
' 	fileValue
' 	--XXXxyxy
' 	content-disposition: form-data; name="data_version"
' 
' 	dataVersion
' 	--XXXxyxy
' 	content-disposition: form-data; name="content2"; filename="XXX"
' 
' 	THE FILE CONTENT GOES HERE...
' 	--XXXxyxy--
' 


' First, let's build the HTTP request object
Dim req As New Chilkat.HttpRequest

req.HttpVerb = "POST"
req.Path = "/cgi/XXX.pl"

' The boundary string is automatically generated and added by Chilkat.
' The value for the boundary string doesn't matter. (As long as it's a unique string that doesn't occur elsewhere in the request.)
req.ContentType = "multipart/form-data"

' Adding the Connection: Keep-Alive is optional.  It only makes sense if the intent is to send
' additional requests to the same domain (your-namespace-sb.accesscontrol.windows.net) within a reasonable time period.
req.AddHeader("Connection","Keep-Alive")

' --------------------------------------------------
' IMPORTANT: Never set the Content-Length header.  
' Chilkat will automatically compute the correct Content-Length and will add it.
' --------------------------------------------------

' If a specific User-Agent header field is needed, it can be added by calling AddHeader.
req.AddHeader("User-Agent","XXX/8.0.15")

' The "Accept" header, if present, tells the server what Content-Type responses will be accepted.
' In this case, we're telling the server that we'll only accept "text/html" responses, and therefore
' the server SHOULD only send a text/html response.  Technically, the Accept header is not required.
req.AddHeader("Accept","text/html")

' Add the params to the request.  Given that the Content-Type is set to "multipart/form-data", when
' Chilkat composes the request, it will put each param in it's own MIME sub-part (i.e. in it's own
' part delimited by the boundary string).
req.AddParam("UploadAgent","InterfaceVersion1.5")
req.AddParam("user","userValue")
req.AddParam("password","passwordValue")
req.AddParam("file","fileValue")
req.AddParam("data_version","dataVersion")

' The last param is the contents of a file.
' If it's a file on disk, we can add it like this:
Dim pathToFileOnDisk As String = "c:/someDir/someFile.dat"
Dim success As Boolean = req.AddFileForUpload("content2",pathToFileOnDisk)
If (success <> True) Then
    Debug.WriteLine(req.LastErrorText)
    Exit Sub
End If


' Alternatively, if the contents of the file are in memory, perhaps in a string
' variable, the file can be added like this instead.
Dim fileContents As String = "This is the content of the file being uploaded."
success = req.AddStringForUpload("content2","XXX",fileContents,"utf-8")

' -----------------------------------------------------------
' IMPORTANT: To duplicate the HTTP request shown above, you'll want to choose 
' either AddStringForUpload or AddFileForUpload, but not both.  It's possible to upload
' any number of files by calling AddStringForUpload and/or AddFileForUpload any number
' of times, once per file to be uploaded.  This of course assumes that the receiving
' end is programmed to receive multiple files..
' ------------------------------------------------------------

Dim http As New Chilkat.Http

' The request is ready... now send it using HTTPS (which is port 443 by default).

Dim resp As Chilkat.HttpResponse = Await http.SynchronousRequestAsync("www.myserver.com",443,True,req)
If (http.LastMethodSuccess <> True) Then
    Debug.WriteLine(http.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("HTTP response status: " & resp.StatusCode)

' In this case, the response would be HTML because our Accept header
' told the server to only return HTML.  The HTML is available on the BodyStr
' property of the response object:
Dim htmlStr As String = resp.BodyStr
Debug.WriteLine("Received:")
Debug.WriteLine(htmlStr)