title: How to get apple id from In-app Purchase transaction_id
body: <p>In my application when user will buy any product using In- app Purchase i can not force user please log in in my application [ That is apple condition] </p>
  
  <p>When a user will buy any product apple just give a in app purchase <strong>transaction_id</strong> . </p>
  
  <p>In that case i can not keep track any users information in my system.
  later when the user will restore his In - app purchase product in another device, without any user track/ apple id/ Unique ID i can not manage my application.  </p>
  
  <p>how to i can get apple users unique id by transaction_id..?</p>