Javascript-未捕获即使已被拒绝的承诺也被拒绝了 [英] Javascript -Uncaught A promise was rejected even though it had already been rejected

问题描述

我正在运行此Parse.com云代码作业.它查询我的一个类并获取URL，然后读取这些URL(它们是xml文件)，然后从它们中获取一些数据并将其保存以进行解析.从代码中可以看出.

I have this Parse.com cloud code job, that I am running. It queries one of my classes and gets url's, then I read these urls, which are xml files, and I get some data from them and save it to parse. As can be seen in the code.

这是代码

此处的完整代码 gist.github.com/gouegd/aae61aa08b8295d52b08

当我运行此云代码作业时.在控制台中.我看到此消息

When I run this cloud code job. In the console. I see this message

Failed with: Uncaught A promise was rejected even though it had already been rejected.

这是因为一些URL无效，然后代码中断了.

This is coming up because some of the urls are not valid, and then the code breaks.

基本上，我需要一种在其中一个URL不起作用且没有代码停止的情况下处理它的方法！并继续使用其他网址.

Basically I need a way to handle it when one of the URL isn't working and not have the code stop!! And continue with the other urls.

此问题发生在第77-83行之间，其中传递了url变量，因此我需要它忽略错误的url，然后继续处理其余的url.

This problem occurs between line 77-83, where the url variable is being passed, so I need it to ignore bad urls and then keep going with the rest of the urls.

非常感谢您的帮助.

推荐答案

这是一个奇怪的错误消息.

That's a weird error message.

据我所知...

在第89行和第90行之间插入:

Between lines 89 and 90 insert :

    }, function() {
        return Parse.Promise.as();//return resolved promise to keep the promise chain going.

给予:

return Parse.Cloud.httpRequest({
    url: url,
    //data: ... //some properties of menuItem?
}).then(function(httpResponse) {
    return readResponse_async(httpResponse.text).then(function(res) {
        if (res.menu.day.at(dayNumber).meal) {

            return saveMeals_async(res.menu.day.at(dayNumber).meal, school, diningHallNumber, menuLocation);
        } else {
            return Parse.Promise.as();//return resolved promise to keep the promise chain going.
        }
    }, function() {
        return Parse.Promise.as();//return resolved promise to keep the promise chain going.
    });
});

或低一排:

return Parse.Cloud.httpRequest({
    url: url,
    //data: ... //some properties of menuItem?
}).then(function(httpResponse) {
    return readResponse_async(httpResponse.text).then(function(res) {
        if (res.menu.day.at(dayNumber).meal) {

            return saveMeals_async(res.menu.day.at(dayNumber).meal, school, diningHallNumber, menuLocation);
        } else {
            return Parse.Promise.as();//return resolved promise to keep the promise chain going.
        }
    });
}, function() {
    return Parse.Promise.as();//return resolved promise to keep the promise chain going.
});

编辑

由于这两个方法均未处理该错误，因此您可以尝试这样做，虽然我认为Parse的承诺不是可投掷安全的"，但这种方法很杂乱但可以忍受:

As both of those have failed to handle the error, you might try this, which is messy but tolerable if, as I suspect, Parse's promises are not "throw-safe" :

return Parse.Cloud.httpRequest({
    url: url,
    //data: ... //some properties of menuItem?
}).then(function(httpResponse) {
    try {
        return readResponse_async(httpResponse.text).then(function(res) {
            if (res.menu.day.at(dayNumber).meal) {
                return saveMeals_async(res.menu.day.at(dayNumber).meal, school, diningHallNumber, menuLocation);
            } else {
                throw new Error();
            }
        });
    }
    catch(e) {
        return Parse.Promise.as();//return resolved promise to keep the promise chain going.
    }
}, function() {
    return Parse.Promise.as();//return resolved promise to keep the promise chain going.
});

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