ajax resender for backbone

savemsg.js

/*
*  This View handles failing backbone requests
*  it will display the savestate on #savemsg
*  it will resend failed packages after a exponential increasing amount of time
*/
window.View.SaveMsg = Backbone.View.extend({
        el: $("#savemsg"),

        events: {
            "click a.resend": "resend",
        },

        failed_xhr: [],

        resent: Date.now(),

        reconnect_attempts: 0,

        last_transfer: new Date(),

        initialize: function() {
            this.msg_welcome();
            var self = this;
            $(this.el).ajaxComplete(function() {
                self.handle_complete.apply(self, arguments)
            });
        },

        resend: function() {
            this.resent = Date.now();
            while (this.failed_xhr.length > 0)
            $.ajax(this.failed_xhr.pop());
        },

        handle_complete: function(event, request, options) {
            var result = parseInt(request.status / 100);

            if (result == 4) {
                this.failed_xhr.push(options);
                this.begin_retry();
                this.msg_lost_connection();
            }
            else if (result == 5) {
                this.msg_internal_error(request.status);
            }
            else {
                if (this.reconnect_attempts > 0) this.msg_reconnected();
                else this.msg_saved();
                this.reconnect_attempts = 0;
                this.last_transfer = new Date();
            }
        },

        begin_retry: function() {

            //am i already retrying to send this stuff?
            if (this.failed_xhr.length > 1)
            return;

            this.retry_in(5 * Math.pow(2, this.reconnect_attempts++));
        },

        retry_in: function(seconds, init_time) {
            init_time || (init_time = Date.now())

            //it was resent manually
            if (this.resent > init_time) return;

            $(this.el).html("Connection lost since " + this.time(this.last_transfer) + ". Retrying in " + seconds + " seconds (<a href='#' class='resend'>retry now</a>)");
            if (seconds > 0) {
                var self = this
                window.setTimeout(function() {
                    self.retry_in.call(self, seconds - 1, init_time);
                },
                1000);
            }
            else {
                this.resend();
            };

        },

        time: function(date) {
            d = date || new Date();

            hours = d.getHours();
            minutes = d.getMinutes() + "";

            if (minutes.length == 1)
            minutes = "0" + minutes;

            return hours + ":" + minutes;
        },

        blinking: false,

        blink: function(times, speed) {
            if (!this.blinking) {
                if (times > 0) {
					self = this;
                    $(this.el).fadeToggle(speed, 'swing', function(){self.blinking = times!=1;})
                    this.blink(times - 1, speed)
                    this.blinking = true;
                }
            }
        },

        set_status_text: function(text) {
            $(this.el).text(text)
            this.blink(4, 500);
        },

        msg_welcome: function() {
            this.set_status_text("Welcome at Osamos!");
        },

        msg_saved: function() {
            this.set_status_text("saved at " + this.time());
        },

        msg_reconnected: function() {
            this.set_status_text("saved at " + this.time());
            $.flash("Reconnected! Your data are safe - at least for now.");
        },

        msg_lost_connection: function() {
            $.flash("Connection lost since " + this.time(this.last_transfer) + ". Youre data may be lost if you don't reconnect us!", {
                type: "error"
            })
        },

        msg_internal_error: function(status) {
            this.set_status_text("Internal Error ( " + status + " ). Try again or contact the support team!");
            $.flash("An internal error occured! Your data are probably not saved...", {
                type: "error"
            })
        }

});