(Visual Basic 6.0) 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 ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

' 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 ChilkatJsonObject
success = jsonToken.LoadFile("qa_data/tokens/paypal.json")

' Build the Authorization request header field value.
Dim sbAuth As New ChilkatStringBuilder
' token_type should be "Bearer"
success = sbAuth.Append(jsonToken.StringOf("token_type"))
success = sbAuth.Append(" ")
success = 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 ChilkatRest
Dim bAutoReconnect As Long
bAutoReconnect = 1
Dim success As Long
success = rest.Connect("api.sandbox.paypal.com",443,1,bAutoReconnect)
If (success <> 1) Then
    Debug.Print 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 ChilkatJsonObject
json.EmitCompact = 0
success = json.UpdateString("subject","Past due")
success = json.UpdateString("note","Canceling invoice")
success = json.UpdateBool("send_to_merchant",1)
success = json.UpdateBool("send_to_payer",1)
Debug.Print 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 ChilkatStringBuilder
success = sbPath.Append("/v1/invoicing/invoices/invoice_id/cancel")
Dim numReplacements As Long
numReplacements = sbPath.Replace("invoice_id","INV2-XPWZ-NUTQ-LNWB-P8NC")

json.EmitCompact = 1
Dim sbRequestBody As New ChilkatStringBuilder
Dim sbResponseBody As New ChilkatStringBuilder

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

success = rest.FullRequestSb("POST",sbPath.GetAsString(),sbRequestBody,sbResponseBody)
If (success <> 1) Then
    Debug.Print rest.LastErrorText
    Exit Sub
End If

Debug.Print "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.Print sbResponseBody.GetAsString()
    Debug.Print "Failed."
    Exit Sub
End If

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