(VB.NET UWP/WinRT) PayPal - Cancel Sent Invoice

Cancels a sent invoice, by ID, and, optionally, sends a notification about the cancellation to the payer, merchant, and Cc: emails.

Note: This example requires Chilkat v9.5.0.65 or greater.

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

' Note: Requires Chilkat v9.5.0.65 or greater.

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

' Load our previously obtained access token. (see PayPal OAuth2 Access Token)
Dim jsonToken As New Chilkat.JsonObject
jsonToken.LoadFile("qa_data/tokens/paypal.json")

' Build the Authorization request header field value.
Dim sbAuth As New Chilkat.StringBuilder
' token_type should be "Bearer"
sbAuth.Append(jsonToken.StringOf("token_type"))
sbAuth.Append(" ")
sbAuth.Append(jsonToken.StringOf("access_token"))

' Make the initial connection.
' A single REST object, once connected, can be used for many PayPal REST API calls.
' The auto-reconnect indicates that if the already-established HTTPS connection is closed,
' then it will be automatically re-established as needed.
Dim rest As New Chilkat.Rest
Dim bAutoReconnect As Boolean = True
Dim success As Boolean = Await rest.ConnectAsync("api.sandbox.paypal.com",443,True,bAutoReconnect)
If (success <> True) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


' ----------------------------------------------------------------------------------------------
' The code above this comment could be placed inside a function/subroutine within the application
' because the connection does not need to be made for every request.  Once the connection is made
' the app may send many requests..
' ----------------------------------------------------------------------------------------------

' Build the JSON request body containing the reminder information:
Dim json As New Chilkat.JsonObject
json.EmitCompact = False
json.UpdateString("subject","Past due")
json.UpdateString("note","Canceling invoice")
json.UpdateBool("send_to_merchant",True)
json.UpdateBool("send_to_payer",True)
Debug.WriteLine(json.Emit())

' The JSON created by the above code:

' 	{ 
' 	  "subject": "Past due",
' 	  "note": "Canceling invoice",
' 	  "send_to_merchant": true,
' 	  "send_to_payer": true
' 	}


' Build a path using a previously-sent invoice ID.
Dim sbPath As New Chilkat.StringBuilder
sbPath.Append("/v1/invoicing/invoices/invoice_id/cancel")
Dim numReplacements As Integer = sbPath.Replace("invoice_id","INV2-XPWZ-NUTQ-LNWB-P8NC")

json.EmitCompact = True
Dim sbRequestBody As New Chilkat.StringBuilder
Dim sbResponseBody As New Chilkat.StringBuilder

rest.AddHeader("Content-Type","application/json")
rest.AddHeader("Authorization",sbAuth.GetAsString())
json.EmitSb(sbRequestBody)

success = Await rest.FullRequestSbAsync("POST",sbPath.GetAsString(),sbRequestBody,sbResponseBody)
If (success <> True) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Response Status Code = " & rest.ResponseStatusCode)

' In our testing, we received a 204 response, which is a success HTTP response code, but 
' differs from the PayPal REST API reference documentation, which states that a 202 response
' is expected.  I suspect an error in the PayPal documentation, or in the PayPal responder.
' Check for either 202 or 204..
' Did we get a 202 accepted response?
If ((rest.ResponseStatusCode <> 202) And (rest.ResponseStatusCode <> 204)) Then
    Debug.WriteLine(sbResponseBody.GetAsString())
    Debug.WriteLine("Failed.")
    Exit Sub
End If


' The 202/204 response should be empty.  (Again, our experience differs from the online PayPal documentation..)
Debug.WriteLine("Success.")