BUGFIX: prevent form from expiring on users - ping regularly.

The form throws a CSRF error if left for too long by itself. This is
especially important for long forms.

Use local ping function, as the CMS ping returns 403 when BasicAuth is
enabled.

code/model/UserDefinedForm.php

@@ -298,6 +298,7 @@ class UserDefinedForm_Controller extends Page_Controller {
 		// load the jquery
 		Requirements::javascript(FRAMEWORK_DIR .'/thirdparty/jquery/jquery.js');
 		Requirements::javascript('userforms/thirdparty/jquery-validate/jquery.validate.min.js');
+		Requirements::javascript('userforms/javascript/UserForm_frontend.js');
 	}
 	
 	/**
@@ -325,6 +326,13 @@ class UserDefinedForm_Controller extends Page_Controller {
 		);
 	}
 
+	/**
+	 * Keep the session alive for the user.
+	 */
+	function ping() {
+		return 1;
+	}
+
 	/**
 	 * Get the form for the page. Form can be modified by calling {@link updateForm()}
 	 * on a UserDefinedForm extension

javascript/UserForm_frontend.js

@@ -0,0 +1,9 @@
+jQuery(function($) {
+	/**
+	 * Make sure the form does not expire on the user.
+	 */
+	setInterval(function() {
+		// Ping every 3 mins.
+		$.ajax({url: "UserDefinedForm_Controller/ping"});
+	}, 180*1000);
+});