title: What is being sent via cookie from my browser, that might trigger a POST method versus a GET method from Paypal?
body: <p>I'm using the Paypal Classic API via Sandbox as shown in <a href="http://railscasts.com/episodes/143-paypal-security" rel="nofollow noreferrer">Railscast 143</a> in Rails 4x and Ruby 2x deployed on Heroku.</p>
  <p>The User should be able to add purchases to a cart, and upon clicking a button is routed to Paypal to complete the transaction.  Once the purchase is completed, a payment notification is sent to the notification_url, and then the browser is redirected to the return_url, which is the same page the user was on before.  I'm using Railscasts' SSL to encrypt.</p>
  <p>Everything works except the return URL.</p>
  <p>I've noticed that for any new browser in a new computer, after the purchase is completed on Paypal, the browser does not return to the proper URL.  However, once I manually go back to the last page on my site and refresh, showing the purchase has been made properly, I can go through the process again to buy another item, and the return url works.  The 2nd time around, the Paypal window looks a bit different, because it remembers the user from the last transaction.</p>
  <p>Even if I clear cookies and all history for a browser, Paypal will still remember and the method will succeed.</p>
  <p>When I look at my logs, I see that the difference between success and failure is that in the success, there is a POST method being sent to my return URL, which is Projects/purchase.</p>
  <p>In the failed version, there is a GET method being sent to the return URL, which is wrong.</p>
  <p>Here is the log of a success: <a href="https://gist.github.com/allenwlee/1f51a4dac884ba25ba5f" rel="nofollow noreferrer">https://gist.github.com/allenwlee/1f51a4dac884ba25ba5f</a></p>
  <p>Here is the log of a failure: <a href="https://gist.github.com/allenwlee/dff86f7de2f16951f512" rel="nofollow noreferrer">https://gist.github.com/allenwlee/dff86f7de2f16951f512</a></p>
  <p>Here's all my relevant code:  <a href="https://gist.github.com/allenwlee/9e24ae7384a0f5e9bff2" rel="nofollow noreferrer">https://gist.github.com/allenwlee/9e24ae7384a0f5e9bff2</a></p>