Question

I am working on a asp.net mvc3 application.

I have this Jquery function

    function CheckSession() {
        $.ajax({
            type: 'POST',
            url: '@Url.Action("CheckSession", "Home")',
            success: function (isAvailable) {
                return isAvailable;
            },
            complete: function (owner) {

            },
            error: function (owner) {
                alert('Error Getting session');
                return false;
            }

        });
    }

Basically what this session does is call an action from the HomeController that action will return true or false.

What I want to do is this,
Before every ajax call in the application I want to first use this function. and if it return true we procede with the call, else we dont do anything.

Is there a way to do this Without having to go through all the code and call it before every ajax call

I know this can be done by calling it before every ajax and testing the return, but i have tons of ajax calls.

What I’m looking for is an event handler that fires before any ajax call is made

something like this:

$(ajax).beforeCall(function (event) {
    if (CheckSession()){
        event.ProceedWithCall;
    }
    else {
         //Stop the call;
         return false;
    }
});

Answer 1

You can use ajaxSetup and set the beforeSend function like this:

$.ajaxSetup({
  beforeSend: function(){
            return !CheckSession();
      }
});

beforeSend docs:

A pre-request callback function that can be used to modify the jqXHR (in jQuery 1.4.x, XMLHTTPRequest) object before it is sent. Use this to set custom headers, etc. The jqXHR and settings maps are passed as arguments. This is an Ajax Event. *Returning false in the beforeSend function will cancel the request.

ajaxSetup docs:

Description: Set default values for future Ajax requests.