Dart

PayPal - Cancel Sent Invoice

See more PayPal Examples

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.

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // 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)
  final jsonToken = CkJsonObject();
  jsonToken.loadFile('qa_data/tokens/paypal.json');

  // Build the Authorization request header field value.
  final sbAuth = CkStringBuilder();
  // 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.
  final rest = CkRest();
  final bAutoReconnect = true;
  try {
    rest.connect('api.sandbox.paypal.com', 443, true, bAutoReconnect);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // ----------------------------------------------------------------------------------------------
  // 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:
  final json = CkJsonObject();
  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);
  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.
  final sbPath = CkStringBuilder();
  sbPath.append('/v1/invoicing/invoices/invoice_id/cancel');
  final numReplacements = sbPath.replace('invoice_id', 'INV2-XPWZ-NUTQ-LNWB-P8NC');

  json.emitCompact = true;
  final sbRequestBody = CkStringBuilder();
  final sbResponseBody = CkStringBuilder();

  rest.addHeader('Content-Type', 'application/json');
  rest.addHeader('Authorization', sbAuth.getAsString());
  json.emitSb(sbRequestBody);

  try {
    rest.fullRequestSb('POST', sbPath.getAsString(), sbRequestBody, sbResponseBody);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  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) && (rest.responseStatusCode != 204)) {
    print(sbResponseBody.getAsString());
    print('Failed.');
    return;
  }

  // The 202/204 response should be empty.  (Again, our experience differs from the online PayPal documentation..)
  print('Success.');
}