追踪承诺中未捕获的错误

Question

我正在为 Firefox 编写一个扩展，以允许我从网站上抓取一些数据。

一个简单的描述是该站点包含一个索引页面，其中包含指向包含我想要的数据的子页面的链接列表。我浏览到扩展程序检测到 URL 的索引页面，并询问我是否要抓取它。如果我说是，内容脚本会抓取子页面列表 URLs 并将它们传递给后台进程，后台进程应该在新选项卡中依次打开每个页面，抓取数据，然后关闭选项卡。为了避免服务器出现问题，我设置了一系列超时来创建新选项卡，目前以 10 秒为间隔。

收集完所有数据后，需要将其传递给服务器上的 PHP 脚本，但这超出了本问题的范围。

除了我在控制台上看到打开和关闭的每个选项卡（选项卡编号不同）时出现此消息外，所有这些都按描述工作：

15:06:27.426 Uncaught (in promise) Error: Invalid tab ID: 171

一天中的大部分时间我都对此感到困惑，但我无法找到此错误的根源。这是双重混乱，因为代码完全符合我的要求。

问题：这个错误是从哪里来的，我需要做什么来修复它？

代码如下：

async function backgroundProcess() {
    "use strict";
    // delay in ms between each new tab. Set to some reasonable value after testing.
    const   newTabDelay = 5000;


    let tabList = [];
    let resultList = [];


    async function createTab(url, resolve, reject) {

        try {
            //Create a tab and open the link. Return a promise so that we can wait for everything to complete
            let tabId = await browser.tabs.create({url: url});
            console.log("executing script in tab " + tabId.id);
            let tabData = await browser.tabs.executeScript(
                tabId.id,
                {
                    file: 'scrapeMileage.js'
                });

            console.log("Content script executed");
            console.log(tabData);
            //resultList.push(tabData);
            let tabNumber = tabId.id;
            console.log("Removing tab Tab ID " + tabNumber);
            await browser.tabs.remove(tabNumber);
            console.log("Removed tab Tab ID " + tabNumber);

            resolve(tabData);
        } catch (e) {
            console.log("createTab catch "+e);
            reject(e);
        }
    }
    async function tabOpener(linkList) {

        try {
            console.log("Tab opener now running");
            //linkList.forEach((el)=>{console.log("(background) Link found:"+el)});

            // Loop through the list opening upo a new tab every few seconds
            for (let i = 0; i < Math.min(5, linkList.length); i++) {
                console.log("Creating tab for " + linkList[i]);
                tabList.push(new Promise((resolve, reject) => {
                    setTimeout(function () {
                        createTab(linkList[i], resolve, reject);
                    }, newTabDelay * i);
                }));
            }
            resultList = await Promise.all(tabList);
            console.log("Scraping complete");
            console.log(resultList);
        } catch (e) {
            console.log("tabOpener catch:"+e);
        }
    }

    function listener(message, sender, respond) {

        console.log("Received message: "+message.messageType);
        console.log(message);

        switch (message.messageType) {
            case 'mileageData':
                break;
            case 'scrapeRequest':
                console.log("Calling tab opener")
                tabOpener(message.data)
                break;

        }

    }
    console.log("Setting up message listener");
    browser.runtime.onMessage.addListener(listener);


}
console.log("Running background process");
backgroundProcess();

代码中大量添加了 console.log() 以帮助调试。这是控制台输出。

15:05:57.459 Webconsole context has changed
15:05:57.462 Running background process background.js:81:9
15:05:57.463 Setting up message listener background.js:76:13
15:06:05.357 Received message: scrapeRequest background.js:62:17
15:06:05.357
Object { messageType: "scrapeRequest", data: (17) […] }
background.js:63:17
15:06:05.358 Calling tab opener background.js:69:25
15:06:05.358 Tab opener now running background.js:40:21
15:06:05.358 Creating tab for https://drivers.uber.com/p3/payments/trips/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx background.js:45:25
15:06:05.359 Creating tab for https://drivers.uber.com/p3/payments/trips/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx background.js:45:25
15:06:05.359 Creating tab for https://drivers.uber.com/p3/payments/trips/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx background.js:45:25
15:06:05.359 Creating tab for https://drivers.uber.com/p3/payments/trips/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx background.js:45:25
15:06:05.359 Creating tab for https://drivers.uber.com/p3/payments/trips/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx background.js:45:25
15:06:05.387 executing script in tab 167 background.js:16:21
15:06:06.895 Content script executed background.js:23:21
15:06:06.895
Array [ {…} ]
background.js:24:21
15:06:06.896 Removing tab Tab ID 167 background.js:27:21
15:06:06.905 Removed tab Tab ID 167 background.js:29:21
15:06:06.906 Uncaught (in promise) Error: Invalid tab ID: 167 undefined
15:06:10.371 executing script in tab 168 background.js:16:21
15:06:11.451 Content script executed background.js:23:21
15:06:11.451
Array [ {…} ]
background.js:24:21
15:06:11.452 Removing tab Tab ID 168 background.js:27:21
15:06:11.461 Removed tab Tab ID 168 background.js:29:21
15:06:11.461 Uncaught (in promise) Error: Invalid tab ID: 168 undefined
15:06:15.372 executing script in tab 169 background.js:16:21
15:06:16.751 Content script executed background.js:23:21
15:06:16.751
Array [ {…} ]
background.js:24:21
15:06:16.752 Removing tab Tab ID 169 background.js:27:21
15:06:16.762 Removed tab Tab ID 169 background.js:29:21
15:06:16.765 Uncaught (in promise) Error: Invalid tab ID: 169 undefined
15:06:20.385 executing script in tab 170 background.js:16:21
15:06:21.481 Content script executed background.js:23:21
15:06:21.481
Array [ {…} ]
background.js:24:21
15:06:21.482 Removing tab Tab ID 170 background.js:27:21
15:06:21.489 Removed tab Tab ID 170 background.js:29:21
15:06:21.490 Uncaught (in promise) Error: Invalid tab ID: 170 undefined
15:06:25.382 executing script in tab 171 background.js:16:21
15:06:27.414 Content script executed background.js:23:21
15:06:27.414
Array [ {…} ]
background.js:24:21
15:06:27.414 Removing tab Tab ID 171 background.js:27:21
15:06:27.423 Removed tab Tab ID 171 background.js:29:21
15:06:27.423 Scraping complete background.js:53:21
15:06:27.423
Array(5) [ (1) […], (1) […], (1) […], (1) […], (1) […] ]
background.js:54:21
15:06:27.426 Uncaught (in promise) Error: Invalid tab ID: 171 undefined

一些注意事项：

scrapeMileage.js 脚本目前除了 return 一个固定值外什么都不做。
数据是与我有关的数据，仅出于我的目的而检索。一旦这个工作正常，我希望只抓取每个页面一次。
出于隐私原因，我混淆了实际涉及的 URL。

Answer 1

从完整日志来看，错误肯定是browser.tabs.remove产生的。事实上，运行它在 devtools 控制台中手动使用不存在的选项卡 ID 将产生相同的错误消息。例如，如果其他东西已经关闭了选项卡，就会发生这种情况。

这个错误在异步代码中被标准 try/catch 简单地拦截了，就像你已经做的一样。如果您的代码没有拦截此错误，我看到的唯一解释是 Firefox 中的错误或 browser 的不正确的 polyfill。在 Firefox 中不需要这个 polyfill。

追踪承诺中未捕获的错误

Tracking down an uncaught error in a promise

javascript

promise

firefox-addon-webextensions