[keycloak-dev] new browser back button behavior

PR is building... Browser back button will now either restart the flow (and create a new client session) or not allow you off your current page depending on the protocol and where you are in the flow. * If your protocol is initiated by a GET request and the back button brings you to the 1st rendered page (username/password) this starts a new flow * If your protocol is initiated by a POST request (SAML Post binding) things work a bit differently. This initial post request will redirect you to the "authenticate" URL. Then if your back button brings you to the username/password page, you will not see it and just stay on your current page. * If your back button click brings you to the 2nd page in the flow, you will just be stuck on your current page. Try it out. Hopefully all these refresh and back button issues are done now. Some changes to make this happen: * The "code" in the URL o the flow used to be generated by hashing the current action key, the current action (AUTHENTICATE, REQUIRE_ACTION), and the realm secret key. The action key changed whenever you changed the current action...NOW the action key does NOT change for the whole flow. The action key is automatically generated once when you create the ClientSession and never changed again. * Consent page no longer changes the current action to OAUTH_GRANT. Consent page is now considered a REQUIRED_ACTION action and treated as such. This was to support back button here too. * Cache-Control: no-store, must-revalidate, max-age=0 is now set in the response for every endpoint on LoginActionsService and any protocol entry point. -- Bill Burke JBoss, a division of Red Hat http://bill.burkecentral.com