Expose CSRF Token refresh as a function

Refreshing CSRF tokens ensures that forms do not contain cached tokens.
This is currently done once, when jquery-ujs is loaded. If a cached form
is later loaded onto the page (say via a remote form for 'load more'),
the CSRF token is not udated.

This change exposes the CSRF token refreshing code at
`$.rails.refreshCSRFTokens` so it can be called at will without developers
having to re-implement the function.

Author: derekprior

src/rails.js

@@ -57,6 +57,13 @@
       if (token) xhr.setRequestHeader('X-CSRF-Token', token);
     },
 
+    // making sure that all forms have actual up-to-date token(cached forms contain old one)
+    refreshCSRFTokens: function(){
+      var csrfToken = $('meta[name=csrf-token]').attr('content');
+      var csrfParam = $('meta[name=csrf-param]').attr('content');
+      $('form input[name="' + csrfParam + '"]').val(csrfToken);
+    },
+
     // Triggers an event on an element and returns false if the event result is false
     fire: function(obj, name, data) {
       var event = $.Event(name);
@@ -384,10 +391,7 @@
     });
 
     $(function(){
-      // making sure that all forms have actual up-to-date token(cached forms contain old one)
-      var csrfToken = $('meta[name=csrf-token]').attr('content');
-      var csrfParam = $('meta[name=csrf-param]').attr('content');
-      $('form input[name="' + csrfParam + '"]').val(csrfToken);
+      rails.refreshCSRFTokens();
     });
   }
 

test/public/test/csrf-refresh.js

@@ -0,0 +1,24 @@
+(function(){
+
+module('csrf-refresh', {});
+
+asyncTest('refresh all csrf tokens', 1, function() {
+  var correctToken = "cf50faa3fe97702ca1ae";
+
+  var form = $('<form />')
+  var input = $('<input>').attr({ type: 'hidden', name: 'authenticity_token', id: 'authenticity_token', value: 'foo' })
+  input.appendTo(form)
+
+  $('#qunit-fixture')
+    .append('<meta name="csrf-param" content="authenticity_token"/>')
+    .append('<meta name="csrf-token" content="' + correctToken + '"/>')
+    .append(form);
+
+  $.rails.refreshCSRFTokens();
+  currentToken = $('#qunit-fixture #authenticity_token').val();
+
+  start();
+  equal(currentToken, correctToken);
+});
+
+})();

test/views/index.erb

@@ -1,6 +1,6 @@
 <% @title = "jquery-ujs test" %>
 
-<%= test 'data-confirm', 'data-remote', 'data-disable', 'call-remote', 'call-remote-callbacks', 'data-method', 'override' %>
+<%= test 'data-confirm', 'data-remote', 'data-disable', 'call-remote', 'call-remote-callbacks', 'data-method', 'override', 'csrf-refresh' %>
 
 <h1 id="qunit-header"><%= @title %></h1>
 <div id="jquery-cdn">