CakePHP - Use jQuery to check if user is logged in thru Auth

How can I find out if a user is logged in CakePHP thru the Auth component using jQuery. If a user is logged in allow the action to execute if not display an alert asking the user to log in.

<script>
   $(document).ready(function(){
       $(".voteup").click(function() {
            // var isLoggedIn = ... code needed
            if(isLoggedIn){
                var Id = $(this).children("p").text();
                $(this).children("#article_thumbsUp").load("/comments/voteup/"+Id);
            }else{
                alert('You must be logged in to vote on a comment');
            }
      });
  });
</script>
开发者_StackOverflow中文版

Assuming you have a CommentsController with an action check_login()

public function check_login() {

    // $this->Auth->user() returns NULL or User info for logged in user
    if ($this->Auth->user()) {

        // your user is logged in echo success
        ...

    } else {

        // you user is NOT logged in echo failure
        ...

    }

}

You should not use javascript for this, it's not safe at all. You should check this server-side, in the controller, as shown in the answer by Charles Sprayberry.

Then in javascript you always do the Ajax request (use $.get with a callback), and check the response to display the alert or update the UI.

I was able to fix my problem with the following suggestion. So thanks guys for your help...

commments_controller.php

public function checklogin() {          
    $this->autoRender = false; 
    if ($this->Auth->user()) {
        $loggedIn = 1;
    } else {
        $loggedIn = 0;
    }
    return $loggedIn;
}

jQuery Code

<script>
$(document).ready(function(){
var isLoggedIn = 0;
$.ajax({
    type: "POST",
    url: "/comments/checklogin",
    success: function(msg){
        isLoggedIn = msg;
    }
});
$(".voteup").click(function() {
    if(isLoggedIn == 1){
        var Id = $(this).children("p").text();
        $(this).children("#article_thumbsUp").load("/comments/voteup/"+Id);
    }else{
        alert('You must be logged in to vote');
    }
});
});
</script>

It works nicely... I am not sure if it is the best one but it works