中止长轮询AJAX请求，并重新开始新的参数请求 [英] abort long polling ajax request and restart request with new parameter

问题描述

我如何取消一个Ajax请求，然后再次用新的参数调用它呢？我的code时，previous Ajax请求仍然流连。

how do I cancel an ajax request, then call it again with new parameter? with my code, the previous ajax requests still hang around.

var stats_url = '/stats';
var live_stats_ajax_object = $.ajax();
$(".check-round").on("click", function(){
    live_stats_ajax_object.abort();
    round = $(this).attr('class').split(' ')[0];
    get_live_stats(round);
});

var get_live_stats = function(round) {
    live_stats_ajax_object = $.ajax({
        url: stats_url,
        type: "GET",
        data: 'live_stats=true' + "&event_id=" + $( "#event-list option:selected" ).val()
                    + "&fight_id=" + $( 'input[name=fightlist]:checked' ).val()
                    + "&round=" + round,
        dataType: "json",
        timeout: 3500,
        complete: function(xhr, textStatus) {
           console.log("polling again stats for " + round);            
            if (textStatus != "abort") {
                setTimeout( function() { get_live_stats(round); }, 10000 );
            }
        },     
        success: function(data) {
            console.log("polling and got live stats for " + round);
            console.log(data);
        }           
    })
        .fail(function() {
            console.log("polling failed and couldn't get live stats for " + round);
        })
};

我一直在这几个小时。谢谢

I have been on this for hours. Thanks

推荐答案

编辑，更新

尝试

// create empty object 
var live_stats_ajax_object = {}
// reference for `setTimeout` within `get_live_stats`
, id = null
, stats_url = "/stats"
, get_live_stats = function (round) {
        var eventlist = $( "#event-list option:selected" ).val()
        , fightlist = $( 'input[name=fightlist]:checked' ).val();
        live_stats_ajax_object = $.ajax({
            type: "GET",
            url: stats_url,
            data: "live_stats=true&event_id=" 
                  + eventlist 
                  + "&fight_id="
                  + fightlist
                  + "&round="
                  + round,
            timeout: 3500
        });
        // return `live_stats_ajax_object`
        return live_stats_ajax_object
        .done(function (data, textStatus, jqxhr) {
            console.log("polling and got live stats for " + round + "\n"
                        , data);    
        })
        .fail(function (jqxhr, textStatus, errorThrown) {
            console.log("polling failed and couldn't get live stats for " 
                        + round);
        })
        .always(function (jqxhr, textStatus) {
            if (textStatus !== "abort") {
                // set `id` to `setTimeout`'s `numerical ID`
                // call `get_live_stats()` within `setTimeout`
                id = setTimeout(function () {
                    get_live_stats(round);
                }, 10000);
            }
        });
    };

$(".check-round").on("click", function () {
    var round = $(this).attr('class').split(" ")[0];
    // at initial click `live_stats_ajax_object` is empty object , 
    // not having `jqxhr` `promise` property ; 
    // call `get_live_stats()` , which sets `live_stats_ajax_object`
    // to `$.ajax()` , having `state` property at returned `jqxhr` object
    if (!live_stats_ajax_object.hasOwnProperty("state")) {
        get_live_stats(round);
    } else {
        // if `id` was set during initial call to `get_live_stats()`
        if (id) {
            // `.abort()` previous `live_stats_ajax_object` request ,
            // `clearTimeout()` of `id` , set `id` to `null`
            // call `get_live_stats()` with current `round` argument
            live_stats_ajax_object.abort();
            clearTimeout(id);
            id = null;
            get_live_stats(round);
        }
    }
});

http://jsfiddle.net/guest271314/7wrdo5wr/

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