API 概览 && 编码Tips
文档地址
- github Chrome DevTools Protocol 协议本身的仓库 有问题可以在这里提issue
- github debugger-protocol-viewer 协议API文档的仓库
- API 文档地址 API展示的地方，这个经常用
常用API
- Network 网络请求、Cookie、缓存、证书等相关内容
- Page 页面的加载、资源内容、弹层、截图、打印等相关内容
- DOM 文档DOM的获取、修改、删除、查询等相关内容
- Runtime JavaScript代码的执行，这里面我们可以搞事情~~
编码Tips
- 我们这里不会直接调用Websocket相关的内容来调用chrome的调试命令，而是用chrome-remote-interface 这个封装的库来做，它是基于Promise风格的
- 每一个功能块成为一个单独的
domain,像Network，Page，DOM等都是不同的domain - 几乎每一个个头大的
domain都有enable方法，需要先调用这个方法启用之后再使用 - 各个
domain的接口方法参数都是第一个对象或者说一个Map，不用考虑参数的位置了 - 各个
domain的接口返回值也是一个对象，取对应的key就行 - 参数值和返回值经常是meta信息，经常是各种对象的id信息，而不是具体的对象内容（这里可能需要切一下风格）
编码实例
首先做一个简单的封装，准备API的执行环境，具体可参考前一篇关于工具库的。
const chromeLauncher = require('chrome-launcher');
const chromeRemoteInterface = require('chrome-remote-interface');
const prepareAPI = (config = {}) => {
const {host = 'localhost', port = 9222, autoSelectChrome = true, headless = true} = config;
const wrapperEntry = chromeLauncher.launch({
host,
port,
autoSelectChrome,
additionalFlags: [
'--disable-gpu',
headless ? '--headless' : ''
]
}).then(chromeInstance => {
const remoteInterface = chromeRemoteInterface(config).then(chromeAPI => chromeAPI).catch(err => {
throw err;
});
return Promise.all([chromeInstance, remoteInterface])
}).catch(err => {
throw err
});
return wrapperEntry
};
打开百度，获取页面性能数据，参考 Navigation Timing W3C规范
const wrapper = require('the-wrapper-module');
const performanceParser = (perforceTiming) => {
let timingGather = {};
perforceTiming = perforceTiming || {};
timingGather.redirect = perforceTiming.redirectEnd - perforceTiming.redirectEnd-perforceTiming.redirectStart;
timingGather.dns = perforceTiming.domainLookupEnd - perforceTiming.domainLookupStart;
timingGather.tcp = perforceTiming.connectEnd - perforceTiming.connectStart;
timingGather.request = perforceTiming.responseStart - perforceTiming.requestStart;
timingGather.response = perforceTiming.responseEnd - perforceTiming.responseStart;
timingGather.domReady = perforceTiming.domContentLoadedEventStart - perforceTiming.navigationStart;
timingGather.load = perforceTiming.loadEventStart - perforceTiming.navigationStart;
return timingGather;
};
const showPerformanceInfo = (performanceInfo) => {
performanceInfo = performanceInfo || {};
console.log(`页面重定向耗时:${performanceInfo.redirect}`);
console.log(`DNS查找耗时:${performanceInfo.dns}`);
console.log(`TCP连接耗时:${performanceInfo.tcp}`);
console.log(`请求发送耗时:${performanceInfo.request}`);
console.log(`响应接收耗时:${performanceInfo.response}`);
console.log(`DOMReady耗时:${performanceInfo.domReady}`);
console.log(`页面加载耗时:${performanceInfo.load}`);
};
wrapper.prepareAPI().then(([chromeInstance, remoteInterface]) => {
const {Runtime,Page} = remoteInterface;
Page.loadEventFired(() => {
Runtime.evaluate({
expression:'window.performance.timing.toJSON()',
returnByValue:true //不加这个参数，拿到的是一个对象的meta信息,还需要getProperties
}).then((resultObj) => {
let {result,exceptionDetails} = resultObj;
if(!exceptionDetails){
showPerformanceInfo(performanceParser(result.value))
}else{
throw exceptionDetails;
}
});
});
Page.enable().then(() => {
Page.navigate({
url:'http://www.baidu.com'
})
});
});
打开百度 搜索Web自动化 headless chrome，并爬取首屏结果链接
const wrapper = require('the-wrapper-module');
//有this的地方写成箭头函数要注意，这里会有问题
const buttonClick = function () {
this.click();
};
const setInputValue = () => {
var input = document.getElementById('kw');
input.value = 'Web自动化 headless chrome';
};
const parseSearchResult = () => {
let resultList = [];
const linkBlocks = document.querySelectorAll('div.result.c-container');
for (let block of Array.from(linkBlocks)) {
let targetObj = block.querySelector('h3');
resultList.push({
title: targetObj.textContent,
link: targetObj.querySelector('a').getAttribute('href')
});
}
return resultList;
};
wrapper.prepareAPI({
// headless: false //加上这行代码可以查看浏览器的变化
}).then(([chromeInstance, remoteInterface]) => {
const {Runtime, DOM, Page, Network} = remoteInterface;
let framePointer;
Promise.all([Page.enable(), Network.enable(), DOM.enable(),Page.setAutoAttachToCreatedPages({autoAttach:true})]).then(() => {
Page.domContentEventFired(() => {
console.log('Page.domContentEventFired')
Runtime.evaluate({
expression:`window.location.href`,
returnByValue:true
}).then(result => {
console.log(result)
})
});
Page.frameNavigated(() => {
console.log('Page.frameNavigated')
Runtime.evaluate({
expression:`window.location.href`,
returnByValue:true
}).then(result => {
console.log(result)
})
})
Page.loadEventFired(() => {
console.log('Page.loadEventFired')
Runtime.evaluate({
expression:`window.location.href`,
returnByValue:true
}).then(result => {
console.log(result)
})
DOM.getDocument().then(({root}) => {
//百度首页表单
DOM.querySelector({
nodeId: root.nodeId,
selector: '#form'
}).then(({nodeId}) => {
Promise.all([
//找到 搜索框填入值
DOM.querySelector({
nodeId: nodeId,
selector: '#kw'
}).then((inputNode) => {
Runtime.evaluate({
// 两种写法
// expression:'document.getElementById("kw").value = "Web自动化 headless chrome"',
expression: `(${setInputValue})()`
});
//这段代码不起作用 日狗
// DOM.setNodeValue({
// nodeId:inputNode.nodeId,
// value:'Web自动化 headless chrome'
// });
//上面的代码需求要这么写
// DOM.setAttributeValue({
// nodeId:inputNode.nodeId,
// name:'value',
// value:'headless chrome'
// });
})
//找到 提交按钮setInputValue
, DOM.querySelector({
nodeId,
selector: '#su'
})
]).then(([inputNode, buttonNode]) => {
Runtime.evaluate({
expression: 'document.getElementById("kw").value',
}).then(({result}) => {
console.log(result)
});
return DOM.resolveNode({
nodeId: buttonNode.nodeId
}).then(({object}) => {
const {objectId} = object;
return Runtime.callFunctionOn({
objectId,
functionDeclaration: `${buttonClick}`
})
});
}).then(() => {
setTimeout(() => {
Runtime.evaluate({
expression: `(${parseSearchResult})()`,
returnByValue: true
}).then(({result}) => {
console.log(result.value)
//百度的URL有加密，需要再请求一次拿到真实URL
})
},3e3)
});
})
});
});
Page.navigate({
url: 'http://www.baidu.com'
}).then((frameObj) => {
framePointer = frameObj
});
})
});
