根据获取响应表达来填充数组 [英] Fill an array based on a get response express

问题描述

我有以下server.js获取路由

I have the following server.js get route

app.get('/', function(req, res) {
var url;
var final_res = [];
endpoints.forEach(function(url){
    request(url, function(error,response,body){
        if(!error && response.statusCode == 200){
            final_res.push(url.url);
            console.log(url.url);
        }else{
            res.send(err);
            console.log(err);
        }
    });
});
});

这是我的客户端js，我在其中使用jQuery获取完全相同的内容

And this is my client js where I fetch this exact same get with jQuery

$(document).ready(function() {
$.get('http://localhost:3000/', function(data) {
    console.log(data);
    $("#body").text(data);
});
});

当我打开index.html时，它会正确显示用户界面，而在执行我的server.js的终端中，它会正确显示URL.我无法完成的工作是如何使用jQuery接收到的数据来填充html中的表.我的表中将填充从端点提取的网址.

When I open my index.html it displays the user interface correctly and inside my terminal where I have executing my server.js it correctly displays the url. What I can't accomplish is how to use my data that my jQuery receives in order to populate a table inside my html. My table will be populated with urls that are fetch from my endpoints.

我在nodejs中有一定的背景，但是我不能总结一下.

I have some background in nodejs but I cant wrap this up.

推荐答案

由于您需要知道何时完成多个请求，因此建议您改用request-promise库，以便可以使用promise来跟踪所有请求请求已完成.该库还会自动为您检查statusCode.因此，您可以执行以下操作:

Since you need to know when multiple requests are done, I'd suggest you switch to using the request-promise library so you can use promises to track when all the requests are done. That library also checks the statusCode for you automatically. So, you can do this:

const rp = require('request-promise');

app.get('/', function(req, res) {
    Promise.all(endpoints.map(url => {
        return rp(url).then(r => {
            return url.url;
        }).catch(err => {
            // rather than error, just return null result
            return null;
        })
    })).then(results => {
        // filter out null values, then send array as the response
        res.json(results.filter(item => item !== null));
    }).catch(err => {
        console.log(err);
        res.sendStatus(500);
    });
});

这将并行运行所有请求，但是将按顺序收集结果，这将导致最快的总体运行时间.

This will run all the requests in parallel, but collect the results in order which should result in the fastest overall run time.

如果您希望一次运行它们，则可以使用async/await，如下所示:

If you wanted to run them one a time, you could use async/await like this:

const rp = require('request-promise');

app.get('/', async function(req, res) {
    let results = [];
    for (let url of endpoints) {
        try {
            let r = await rp(url);
            if (r) {
                results.push(url.url);
            }
        } catch(e) {
            // ignore error
        }
    }
    res.json(results);
});

---

编辑2020年1月-维护模式下的request()模块

FYI，request模块及其派生类，例如 request-promise 现在处于维护模式，不会积极开发以添加新功能.您可以在此处了解更多信息.在此表中有一些替代方案，并进行了一些讨论每个.我一直在自己使用 got() ，它是从一开始就使用诺言而构建的，很简单使用.

FYI, the request module and its derivatives like request-promise are now in maintenance mode and will not be actively developed to add new features. You can read more about the reasoning here. There is a list of alternatives in this table with some discussion of each one. I have been using got() myself and it's built from the beginning to use promises and is simple to use.

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