Dart

Refresh a Dynamics CRM OAuth2 Access Token

See more OAuth2 Examples

Demonstrates how to refresh an expiring Dynamics CRM access token using the refresh token. endpoint.

(If a REST API call fails with a 401 unauthorized error, an application can auto-recover by refreshing the access token, and then re-send the request using the new token.)

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // This example requires the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  // We previously obtained an access token and saved the JSON to a file using this example:
  // Get Dynamics CRM OAuth2 Access Token

  // This example will examine the JSON and expiration date, and if near expiration will
  // refresh the access token.

  final json = CkJsonObject();
  try {
    json.loadFile('qa_data/tokens/dynamicsCrm.json');
  } on ChilkatException {
    return;
  }

  // The contents of the JSON look like this:
  // {
  //   "token_type": "Bearer",
  //   "scope": "user_impersonation",
  //   "expires_in": "3599",
  //   "ext_expires_in": "0",
  //   "expires_on": "1524783438",
  //   "not_before": "1524779538",
  //   "resource": "https://mydomain.api.crm.dynamics.com",
  //   "access_token": "...",
  //   "refresh_token": "...",
  //   "id_token": "..."
  // }

  // The "expires_on" value is a Unix time.
  final dtExpire = CkDateTime();
  dtExpire.setFromUnixTime(false, json.intOf('expires_on'));

  // If this date/time expires within 10 minutes of the current system time, refresh the token.

  // OK, we need to refresh the access token by sending a POST...
  // 

  final req = CkHttpRequest();
  req.addParam('grant_type', 'refresh_token');
  req.addParam('redirect_uri', 'http://localhost:3017/');
  req.addParam('client_id', 'DYNAMICS-CRM-CLIENT-ID');
  req.addParam('client_secret', 'DYNAMICS-CRM-SECRET-KEY');
  req.addParam('refresh_token', json.stringOf('refresh_token'));
  req.addParam('resource', 'https://mydynamicsdomain.api.crm.dynamics.com');

  final http = CkHttp();

  req.httpVerb = 'POST';
  req.contentType = 'application/x-www-form-urlencoded';

  final resp = CkHttpResponse();
  try {
    http.httpReq('https://login.microsoftonline.com/DYNAMICS-ENDPOINT-GUID/oauth2/token', req, resp);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Load the JSON response.
  json.load(resp.bodyStr);
  json.emitCompact = false;

  // Show the JSON response.
  print(json.emit());

  print('Response status code: ${resp.statusCode}');

  // If the response status code is not 200, then it's an error.
  if (resp.statusCode != 200) {
    return;
  }

  // If an "expires_on" member does not exist, then add the JSON member by
  // getting the current system date/time and adding the "expires_in" seconds.
  // This way we'll know when the token expires.
  if (!json.hasMember('expires_on')) {
    dtExpire.setFromCurrentSystemTime();
    dtExpire.addSeconds(json.intOf('expires_in'));
    json.appendString('expires_on', dtExpire.getAsUnixTimeStr(false));
  }

  // Save the refreshed access token JSON to a file for future requests.
  final fac = CkFileAccess();
  fac.writeEntireTextFile('qa_data/tokens/dynamicsCrm.json', json.emit(), 'utf-8', false);
}