Preventing duplicate REST calls <p>I'm creating an Android app that calls a PHP bases REST api methods for server side updates.</p> <p>For example, to add reward points to customer, we can use:</p> <p><a href="http://example.com/rest/customer/add/1/20" rel="nofollow">http://example.com/rest/customer/add/1/20</a></p> <p>Where 1 is customer id and 20 is reward points.</p> <p>I was wondering how can I prevent duplicate calls to this URL. If for some reason, this URL is called twice, customer will get 20 more points. There is no such condition that customer cannot get more points on same day.</p> <p>Also, how to prevent this URL to be executed anonymously?</p> <p>Is OAuth 2.0 the best solution or there is something better?</p> <p>Thanks</p>