创建一个可以复制百度文库的Chrome插件

具体如何编写Chrome扩展，可以查看Google提供的API文档。本次我打算编写一个简易版本，右键提供一个上下文菜单，复制文本。一些文本屏蔽的内容较少，也有方法查看。如下图所示。

准备图标

新建文件夹CopyText，这将是我们的插件目录。
前往iconfont选择一个合适的图标，尺寸准备16，32，48，64，128

想要获得代码提示，需要在WebStorm中导入库。

点击download，找到chrome

现在，你就可以获得代码提示功能。

编写清单文件(`manifest.json`)

{"name": "Copy Text","version": "0.1","manifest_version": 3,"background": {"service_worker": "background.js"},"icons": {"16": "icons/copy16.png","32": "icons/copy32.png","48": "icons/copy48.png","64": "icons/copy64.png","128": "icons/copy128.png"}
}

manifest_version非常重要，只能写成数字3，manifest_version2在未来会被废弃。
打开开发者模式并且加载文件夹

编写后台脚本

MV3的后台脚本使用了service worker
我们将要使用到contextMenus，因此需要在manifest.json中声明权限。

查看API文档使用即可。
我尝试了解除阻止右键菜单事件，发现不好处理。因为Event.addEventListener触发事件为匿名函数就不好处理。
为了，我们采取捕获网络请求的方式。Chrome提供了webRequest用于捕获请求，同时完成剪切操作需要scripting和tabs
为此声明权限:

在Chrome中捕获请求

这就是我们要捕获的请求；

async function getPageUrl() {let pagesRequest = []chrome.webRequest.onHeadersReceived.addListener(details => {// console.log(details.url)if (details.url.indexOf('0.json') !== -1) {pagesRequest.push(details.url)}}, {urls: ["https://*.bdimg.com/*"]})return pagesRequest
}

拿到url后排序

urls.sort((u1, u2) => {let q1 = getQuery(u1);let q2 = getQuery(u2);let s1 = q1['x-bce-range'].split('-')[0];let s2 = q2['x-bce-range'].split('-')[0];return s2 - s1})function getQuery(u) {const url = decodeURI(u); // 获取url中"?"符后的字串(包括问号)let query = {};if (url.indexOf("?") !== -1) {const str = url.substr(1);const pairs = str.split("&");for (let i = 0; i < pairs.length; i++) {const pair = pairs[i].split("=");query[pair[0]] = pair[1];}}return query;  // 返回对象
}

将他们拼接成文本


async function collectParagraph(...urls) {let article = ""for (let url of urls) {console.log('当前url:', url);let response = await fetch(url, {"headers": {"accept": "*/*","accept-language": "zh-CN,zh;q=0.9","sec-ch-ua": "\" Not A;Brand\";v=\"99\", \"Chromium\";v=\"98\", \"Google Chrome\";v=\"98\"","sec-ch-ua-mobile": "?0","sec-ch-ua-platform": "\"Windows\"","sec-fetch-dest": "script","sec-fetch-mode": "no-cors","sec-fetch-site": "cross-site"},"referrer": "https://wenku.baidu.com/","referrerPolicy": "strict-origin-when-cross-origin","body": null,"method": "GET","mode": "cors","credentials": "omit"});let result = await response.text()let content = JSON.parse(result.substring(8, result.length - 1));for (let para of content.body) {// console.log(para.c)article += para.c;if (para.ps != null)for (let i = 0; i < para.ps["_enter"]; i++) {article += '\n';}}}return article;
}

复制到剪切板

async function copyText(text) {let currentTab = await getCurrentTab();await chrome.scripting.executeScript({target: {tabId: currentTab.id},func: (text) => {navigator.clipboard.writeText(text).then(function () {console.log("success")}, function () {console.log("failed")});},args: [text]})
}

主函数执行整个过程

(async () => {chrome.runtime.onInstalled.addListener(() => {chrome.contextMenus.create({contexts: ['selection', 'page'],title: "复制文本",id: "copyMenu",})})let urls = await getPageUrl();urls.sort((u1, u2) => {let q1 = getQuery(u1);let q2 = getQuery(u2);let s1 = q1['x-bce-range'].split('-')[0];let s2 = q2['x-bce-range'].split('-')[0];return s2 - s1})async function handleContextMenus(info) {let article = ""if (info.menuItemId === 'copyMenu' && info.selectionText !== undefined) {await copyText(info.selectionText)} else if (info.menuItemId === 'copyMenu' && info.pageUrl.indexOf('https://wenku.baidu.com') !== -1) {article += await collectParagraph(...urls)await copyText(article)}}chrome.contextMenus.onClicked.addListener((async info => {await handleContextMenus(info);}))})();

最后清单文件是:

{"name": "Copy Text","version": "0.1","manifest_version": 3,"author": "叶秋明","description": "复制文本和获取百度文库的内容","background": {"service_worker": "background.js"},"icons": {"16": "icons/copy16.png","32": "icons/copy32.png","48": "icons/copy48.png","64": "icons/copy64.png","128": "icons/copy128.png"},"permissions": ["contextMenus","tabs","scripting","webRequest"],"host_permissions": ["https://wenku.baidu.com/*","https://*.bdimg.com/*","<all_urls>"]
}