Question

My app uses $.ajax heavily. The server returns something like {"STATUS":"RELOGIN"} in case the login has expired. Our app is such that the logout on the server happens if the user does nothing for 20 minutes on the app.

All the posts and gets happen through $.ajax and I want to globally change the $.ajax function so that in case the data returned for a request is {"STATUS":"RELOGIN"} I want to make sure that the user is shown some notification if this happens.

I can put this is as the success handler for all the request

function(data){
if(data.STATUS == "RELOGIN") {
    Notifier.show_error("Login again. Session has expired")
    return
}
// rest of the code depending on the request
}

Where Notifier is something that I have written to show notifications

But I do not think duplication of this code in too many places is a good idea.

I do not want to touch jquery source code. It is beautiful as it is.

Answer 1

This is my idea(http://stackoverflow.com/questions/9815058/extending-jquery-ajax-success-globally):

var LOGIN_ERROR_HAS_HAPPENED = false
var INTERNAL_SERVER_ERRORS = false
$(function(){
    var Original_AJAX_function = $.ajax;
    $.ajax = function(options){
        if(options.success){
            var original_callback = options.success
        }
        else{
            var original_callback = function(){}
        }
        options.success = function(data){
            if(data.STATUS == "RELOGIN") {
                if(!LOGIN_ERROR_HAS_HAPPENED){
                    LOGIN_ERROR_HAS_HAPPENED = true
                    Notifier.warning("Login again. Redirecting to login page")
                    setTimeout(function(){
                        window.location.href = "/login"
                    }, 5000)
                }
                return
            }
            original_callback(data)
        }
        if(options.error){
            var original_failure_call_back = options.error
        }
        else{
            var original_failure_call_back = function(){}
        }
        options.error = function(data){
            if(!INTERNAL_SERVER_ERRORS||!LOGIN_ERROR_HAS_HAPPENED){
                INTERNAL_SERVER_ERRORS = true
                Notifier.warning("Oops! Something went wrong. Let us know and we will fix it" )
            }
            original_failure_call_back(data)
        }
        Original_AJAX_function(options)
    }
})

This I plan to put inside document.ready function