在原始功能之外杀死Ajax会话 [英] Kill Ajax Session Outside of Originating Function

问题描述

我有一个要杀死的AJAX函数，但它不在该函数的范围内.看看:

I have an AJAX function I'd like to kill, but it is outside of the function. Take a look:

function waitForMsg(){

       var heartbeat = $.ajax({
            type: "GET",
            url: "includes/push_events.php",
            tryCount : 0,
            retryLimit : 3,
            async: true,
            cache: false,
            // timeout: 500,

            success: function(data){ 
                console.log(data);
                if(data){
                    if(data.current_date_time){
                        updateTime(data.current_date_time);
                    }
                    if(data.color){
                        console.log("Receiving data");
                        displayAlert(data.color, data.notification_message, data.sound, data.title);
                    }
                    if(data.user_disabled){
                        console.log("Receiving data");
                        fastLogoff();
                        checkDisabled();
                    }       

                }
                setTimeout(
                    waitForMsg,
                    5000 
                );
            },


            error: function(data){
                if (data.status == 500) {
                    console.log("Connection Lost to Server (500)");
                        $.ajax(this);
                } else {
                    console.log("Unknown Error. (Reload)");
                        $.ajax(this);
                }

            },

            dataType: "json"

        });
    };

    // Detect browser open.


    $(document).ready(function(){

        // window.onunload = function(){alert('closing')};

        // mainmode();

        $('#alertbox').click(function(){
                $('#alertbox').slideUp("slow");
        });

        $(document).ready(function(){


    $('#alertbox').click(function(){
            $('#alertbox').slideUp("slow");
    });


    // Check focal point
    var window_focus = true;


           $(window).focus(function() {
                window_focus = true;
                console.log('Focus');
            });

            $(window).blur(function() {
                window_focus = false;
                console.log('Blur');
            });


    setInterval(function(){
        if(window_focus == true){
            console.log('in focus');
            waitForMsg();
        }else{
            console.log('out of focus');
            heartbeat.abort();
        }

    }, 5000);
});




    });

如果您注意到，ajax在文档外部.准备好了.我试图杀死ajax调用，如果用户转到另一个窗口，然后一旦返回到窗口就重新启动调用.开始是可行的，但是如果用户离开窗口，它会给我未定义心跳"的信息.显然，这是因为它在该功能之外.有什么解决方法吗?

If you notice, the ajax is outside of the document.ready. I am trying to kill the ajax calls if the user goes to a different window, then restart the calls once the return to the window. The start works, but if the user goes away from the window, it gives me the "heartbeat is not defined". Obviously this is because its outside of that function. Any work arounds?

推荐答案

我将重构一些代码，以避免使用 setInterval 并清理一些代码.

I'd refactor a bit the code to avoid the usage of setInterval and clean up a bit the code.

您可以抽象对象中的逻辑，例如 Request .您可以在 resume 和 stop 中添加两个方法，这些方法将处理基础AJAX请求的状态.

You can abstract the logic in an object, let's say Request. You can add two methods to resume and stop which will handle the status of the underlying AJAX request.

var Request = function(options){
    var request = this, xhr = null, aborted = false;

    /* Resumes the operation.
     * Starts a new request if there's none running.
     */
    request.resume = function() {
        aborted = false;
        request.retry();
    };

    /* Retry loop.
     */
    request.retry = function(){
        if(!xhr) {
            xhr = $.ajax(options).done(function(){
                request.destroy();
                !aborted && setTimeout(function(){
                    request.retry();
                }, options.timeout);
            });
        }
    };

    /* Aborts the current operation.
     */
    request.abort = function(){
        aborted = true;
        if(xhr) xhr.abort();
        request.destroy();
    };

    /* Destroy.
     */
    request.destroy = function(){
        xhr = null;
    };

    return request;
};

现在，您可以删除 setInterval .

$(function () {
    var request = new Request({
        type: "GET",
        url: "includes/push_events.php",
        timeout: 5000,
        success: function(data){ 
            /* Success handler */
        },
        error: function(data){
            /* Error handler */
        },
        dataType: "json"
    });

    $(window).focus(function () {
        request.resume();
    }).blur(function () {
        request.abort();
    });

    request.resume();
});

Request 构造函数接收 $.ajax 选项，该选项应包含一个附加的 timeout 参数，用于指定请求之间的延迟.

The Request constructor receives the $.ajax options which should contain an additional timeout parameter that specifies the delay between requests.

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