Preventing double HTTP POST

Question

I have made a little app for signing up for an event. User input their data and click \"sign me in\".

Now sometimes people are double in the database, the exact sam

Answer 1

Whenever a page is requested from the server , generate a unique requestToken , save it in server side,mark status as NOT Processed and pass it along with the current requested page. Now whenever a page submit happens , get the requestToken from the "POST"ed data and check the status and save the data or take alternate action.

Most of the banking applications use this technique to prevent double "POST"ing.So this is a time proven & reliable way of preventing double submissions.