Dart

PayPal Generate QR Code

See more PayPal Examples

Generates a QR code for an invoice, by ID.

The QR code is a PNG image in Base64-encoded format that corresponds to the invoice ID.

Note: A QR code can only be generated for an invoice that has been both created and sent.

See also Generate QR Code

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Note: Requires Chilkat v9.5.0.64 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 a path using an invoice ID.
  final sbPath = CkStringBuilder();
  sbPath.append('/v1/invoicing/invoices/invoice_id/qr-code');
  final numReplacements = sbPath.replace('invoice_id', 'INV2-ZG2H-HKAW-PMWU-N6ZR');

  rest.addHeader('Authorization', sbAuth.getAsString());
  // A 500x500 image results in a PNG file of approx. 4K bytes in size.
  rest.addQueryParam('width', '500');
  rest.addQueryParam('height', '500');
  rest.addQueryParam('action', 'pay');

  // Send the GET request and get the PNG image data as base64.
  // A successful JSON response looks like this:
  // {"image":"iVBORw0KGgoAA....AASUVORK5CYII="}
  final sbJsonResponse = CkStringBuilder();
  try {
    rest.fullRequestNoBodySb('GET', sbPath.getAsString(), sbJsonResponse);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final json = CkJsonObject();
  json.emitCompact = false;
  json.loadSb(sbJsonResponse);

  print('Response Status Code = ${rest.responseStatusCode}');

  // Did we get a 200 success response?
  if (rest.responseStatusCode != 200) {
    print(json.emit());
    print('Failed.');
    return;
  }

  // If the 200 response is received, the response body contains the PNG data.
  // Save the PNG to a file.
  final pngData = CkBinData();
  pngData.appendEncoded(json.stringOf('image'), 'base64');
  try {
    pngData.writeFile('qa_output/paypal_qr_code.png');
  } on ChilkatException {
    print('Failed to save PNG file.');
    return;
  }

  print('Success.');
}