(Xojo Plugin) 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.

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// 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
success = 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"
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 Chilkat.Rest
Dim bAutoReconnect As Boolean
bAutoReconnect = True
Dim success As Boolean
success = rest.Connect("api.sandbox.paypal.com",443,True,bAutoReconnect)
If (success <> True) Then
    System.DebugLog(rest.LastErrorText)
    Return
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
success = json.UpdateString("subject","Past due")
success = json.UpdateString("note","Canceling invoice")
success = json.UpdateBool("send_to_merchant",True)
success = json.UpdateBool("send_to_payer",True)
System.DebugLog(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
success = sbPath.Append("/v1/invoicing/invoices/invoice_id/cancel")
Dim numReplacements As Int32
numReplacements = sbPath.Replace("invoice_id","INV2-XPWZ-NUTQ-LNWB-P8NC")

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

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 <> True) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

System.DebugLog("Response Status Code = " + Str(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
    System.DebugLog(sbResponseBody.GetAsString())
    System.DebugLog("Failed.")
    Return
End If

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