前言

在进行某些爬虫任务的时候，我们经常会遇到仅用Http协议难以攻破的情况，比如协议中带有加密参数，破解需要花费大量时间，那这时候就会用Selenium去模拟浏览器进行页面上的元素抓取

大多数情况下我们用Selenium只是爬取一下页面上可见的元素信息或者做一些模拟人工的操作，但页面可见元素的数据字段毕竟有限，有许多有用的字段隐藏在接口响应中的，但是要如何拿到接口响应内容呢？

在网上搜索Selenium如何获取Chrome中Network数据包响应结果，大多数的文章都是Python或者Java，C#的资源少之又少，虽然知道原理，但每个语言之间SDK代码实现相差很大，C#的SDK真的有点魔改，需要自己慢慢摸索

探索

通过寻找资料，大致就2种方案

方案1：通过Selenium指定本地一个代理去截取所有请求，类似于常见抓包工具的原理，但是C#是没有这种插件，也有可能是我没找到，比如Python和Java有一个叫Browsermob-Proxy的插件，可以和Selenium深度结合实现代理抓包。我利用FiddlerCore做了一个本地代理工具，但是并不好用，不能和Selenium进行深度绑定使用，会导致Selenium爬取过程和请求截取是异步进行的，强行用代码实现同步又很难受，达不到我想要的要求

方案2：Selenium通过chromedriver开启浏览器的性能日志功能，记录类型为Performance的日志，该功能在Selenium中叫做 PerformanceLoggingPreferences。网页加载完成后，可以通过Selenium拿到浏览器Performance Logs摘要信息，再利用Log中的RequestId调用Chrome CDP命令去浏览器端获取日志的完整内容。Selenium封装的CDP，本质上还是Http请求，只是带着驱动窗口的SessionId和Chrome的API做交互

方案1参考资料：

https://blog.csdn.net/qq_32502511/article/details/101536325  （Python + Browsermob-Proxy）

https://blog.csdn.net/fontcolor0/article/details/103297635/  （Java + Browsermob-Proxy）

https://www.cnblogs.com/airoot/articles/14888284.html  (C# + FiddlerCore)

方案2参考资料：

https://chromedevtools.github.io/devtools-protocol/  （Chrome DevTools Protocol 介绍）

https://www.jianshu.com/p/615e3c0140a5  （Python + 开启PerfLoggingPref）

https://blog.csdn.net/weixin_49855251/article/details/112281901  (不同日志类型的介绍)

https://blog.csdn.net/bigcarp/article/details/115065730  （Java + 原生CDP协议获取日志内容）

上手

启用Logging：

C#伪代码示例：

首先需要安装最新的Nuget包：OpenQA.Selenium

var option = new ChromeOptions();
option.SetLoggingPreference("performance",OpenQA.Selenium.LogLevel.Info); //启用performance日志，等级为Info即可
option.PerformanceLoggingPreferences = new ChromiumPerformanceLoggingPreferences() {
 IsCollectingNetworkEvents = true //采集网络请求事件
};
using (ChromeDriver driver = new ChromeDriver(driverPath,option,TimeSpan.FromSeconds(5))) {
 driver.Navigate().GoToUrl("https://item.m.jd.com/product/10052422060501.html");
 Thread.Sleep(3 * 1000); //等待页面加载完成
 　　 var logs = driver.Manage().Logs.GetLog("performance"); //获取所有performance日志
}

顺便放个Python代码做个对比：

caps = {
 'browserName': 'chrome',
 'loggingPrefs': {
 'performance': 'Info', //启用performance日志，等级为Info即可 
 },
 'goog:chromeOptions': {
 'perfLoggingPrefs': {
 'enableNetwork': True, //采集网络请求事件
 },
 'w3c': False, 
 },
}
driver = webdriver.Chrome(desired_capabilities=caps)
//TODO 获取日志//.....

分析Logging：

 我们从返回的日志列表里随便挑一个看看原始内容：

{[2022-08-03T08:47:31Z] [Info] {"message":{"method":"Network.responseReceived","params":{"frameId":"78D9BC6F0CBE162DA6779F410AA1500C","hasExtraInfo":true,"loaderId":"33814E6BD702343CF0A2A38C976C772F","requestId":"33814E6BD702343CF0A2A38C976C772F","response":{"connectionId":242,"connectionReused":false,"encodedDataLength":546,"fromDiskCache":false,"fromPrefetchCache":false,"fromServiceWorker":false,"headers":{"access-control-allow-credentials":"true","access-control-allow-headers":"Origin, X-Requested-With, Content-Type, multipart/form-data, Accept, Authorization","access-control-allow-methods":"POST, GET, PATCH, DELETE, PUT, OPTIONS","access-control-allow-origin":"*","access-control-max-age":"3600","cache-control":"no-cache,no-store","content-encoding":"gzip","content-language":"zh-CN","content-type":"text/html;charset=UTF-8","date":"Wed, 03 Aug 2022 08:47:33 GMT","hit":"bj-9153118133147527","server":"jfe","strict-transport-security":"max-age=86400","vary":"Accept-Encoding"},"mimeType":"text/html","protocol":"h2","remoteIPAddress":"106.39.169.120","remotePort":443,"responseTime":1.659516451658764e+12,"securityDetails":{"certificateId":0,"certificateTransparencyCompliance":"compliant","cipher":"AES_256_GCM","issuer":"GlobalSign RSA OV SSL CA 2018","keyExchange":"","keyExchangeGroup":"X25519","protocol":"TLS 1.3","sanList":["*.jd.com","*.360buy.com","*.360buyimg.com","*.3.cn","*.7fresh.com","*.baitiao.com","*.chinabank.com.cn","*.e.jd.com","*.jd.co.th","*.jddglobal.com","*.jd.hk","*.jd.id","*.jdpay.com","*.jd.ru","*.jdworldwide.com","*.jdx.com","*.joybuy.com","*.joybuy.es","*.jr.jd.com","*.k.jd.com","*.m.jd.com","*.m.yhd.com","*.shop.jd.com","*.wangyin.com","*.yhd.com","*.yiyaojd.com","360buy.com","360buyimg.com","3.cn","7fresh.com","baitiao.com","chinabank.com.cn","jd.co.th","jddglobal.com","jd.hk","jd.id","jdpay.com","jd.ru","jdworldwide.com","jdx.com","joybuy.com","joybuy.es","wangyin.com","yhd.com","yiyaojd.com","jd.com"],"signedCertificateTimestampList":[{"hashAlgorithm":"SHA-256","logDescription":"Sectigo 'Mammoth' CT log","logId":"6F5376AC31F03119D89900A45115FF77151C11D902C10029068DB2089A37D913","origin":"Embedded in certificate","signatureAlgorithm":"ECDSA","signatureData":"3045022017A2AC492303F50786758D0B4B63EEB8D031850832031FC5A43139C0CDA5EB4F0221009063F884220327718857A6897B87ED5D9F785FFC97F23BD45C84975A11DE721E","status":"Verified","timestamp":1.634109209345e+12},{"hashAlgorithm":"SHA-256","logDescription":"Google 'Argon2022' log","logId":"2979BEF09E393921F056739F63A577E5BE577D9C600AF8F94D5D265C255DC784","origin":"Embedded in certificate","signatureAlgorithm":"ECDSA","signatureData":"3045022071D6D51A59CAA1764E478598AA8EE34B628C8F856B09CDB8382E090CF5D6D97D022100A8FE17E028BB6D439387721974ED3629B9CC44C90AC524B505B9B2375C75CBB9","status":"Verified","timestamp":1.634109210136e+12},{"hashAlgorithm":"SHA-256","logDescription":"Sectigo 'Sabre' CT log","logId":"5581D4C2169036014AEA0B9B573C53F0C0E43878702508172FA3AA1D0713D30C","origin":"Embedded in certificate","signatureAlgorithm":"ECDSA","signatureData":"3045022015D94080264A3FCA83C0F3DE2B85A703384BB678FEBBE5408B4FF7D30BD40900022100DFBAB7992EE99420724CA35A5C2C252298B750994B0EAA98ACB22992F97D545E","status":"Verified","timestamp":1.634109209393e+12}],"subjectName":"*.jd.com","validFrom":1634109205,"validTo":1668410005},"securityState":"secure","status":200,"statusText":"","timing":{"connectEnd":96.834,"connectStart":19.521,"dnsEnd":19.521,"dnsStart":0,"proxyEnd":-1,"proxyStart":-1,"pushEnd":0,"pushStart":0,"receiveHeadersEnd":217.707,"requestTime":2272960.91089,"sendEnd":97.25,"sendStart":97.03,"sslEnd":96.829,"sslStart":55.726,"workerFetchStart":-1,"workerReady":-1,"workerRespondWithSettled":-1,"workerStart":-1},"url":"https://item.m.jd.com/product/10052422060501.html"},"timestamp":2272961.1294,"type":"Document"}},"webview":"78D9BC6F0CBE162DA6779F410AA1500C"}}

我们格式化一下，可以发现日志里已经包含了请求的大部分描述信息，我们需要遍历过滤出method为Network.responseReceived的日志，当然你也可以再根据其他的一些参数过滤出你要的请求

每个日志都有一个requestId，我们再通过该值调CDP命令[Network.getResponseBody]换取具体内容

{
 "message": {
 "method": "Network.responseReceived",
 "params": {
 "frameId": "78D9BC6F0CBE162DA6779F410AA1500C",
 "hasExtraInfo": true,
 "loaderId": "33814E6BD702343CF0A2A38C976C772F",
 "requestId": "33814E6BD702343CF0A2A38C976C772F",
 "response": {
 "connectionId": 242,
 "connectionReused": false,
 "encodedDataLength": 546,
 "fromDiskCache": false,
 "fromPrefetchCache": false,
 "fromServiceWorker": false,
 "headers": {
 "access-control-allow-credentials": "true",
 "access-control-allow-headers": "Origin, X-Requested-With, Content-Type, multipart/form-data, Accept, Authorization",
 "access-control-allow-methods": "POST, GET, PATCH, DELETE, PUT, OPTIONS",
 "access-control-allow-origin": "*",
 "access-control-max-age": "3600",
 "cache-control": "no-cache,no-store",
 "content-encoding": "gzip",
 "content-language": "zh-CN",
 "content-type": "text/html;charset=UTF-8",
 "date": "Wed, 03 Aug 2022 08:47:33 GMT",
 "hit": "bj-9153118133147527",
 "server": "jfe",
 "strict-transport-security": "max-age=86400",
 "vary": "Accept-Encoding"
 },
 "mimeType": "text/html",
 "protocol": "h2",
 "remoteIPAddress": "106.39.169.120",
 "remotePort": 443,
 "responseTime": 1.659516451658764e+12,
 "securityDetails": {
 "certificateId": 0,
 "certificateTransparencyCompliance": "compliant",
 "cipher": "AES_256_GCM",
 "issuer": "GlobalSign RSA OV SSL CA 2018",
 "keyExchange": "",
 "keyExchangeGroup": "X25519",
 "protocol": "TLS 1.3",
 "sanList": ["*.jd.com", "*.360buy.com", "*.360buyimg.com", "*.3.cn", "*.7fresh.com", "*.baitiao.com", "*.chinabank.com.cn", "*.e.jd.com", "*.jd.co.th", "*.jddglobal.com", "*.jd.hk", "*.jd.id", "*.jdpay.com", "*.jd.ru", "*.jdworldwide.com", "*.jdx.com", "*.joybuy.com", "*.joybuy.es", "*.jr.jd.com", "*.k.jd.com", "*.m.jd.com", "*.m.yhd.com", "*.shop.jd.com", "*.wangyin.com", "*.yhd.com", "*.yiyaojd.com", "360buy.com", "360buyimg.com", "3.cn", "7fresh.com", "baitiao.com", "chinabank.com.cn", "jd.co.th", "jddglobal.com", "jd.hk", "jd.id", "jdpay.com", "jd.ru", "jdworldwide.com", "jdx.com", "joybuy.com", "joybuy.es", "wangyin.com", "yhd.com", "yiyaojd.com", "jd.com"],
 "signedCertificateTimestampList": [{
 "hashAlgorithm": "SHA-256",
 "logDescription": "Sectigo 'Mammoth' CT log",
 "logId": "6F5376AC31F03119D89900A45115FF77151C11D902C10029068DB2089A37D913",
 "origin": "Embedded in certificate",
 "signatureAlgorithm": "ECDSA",
 "signatureData": "3045022017A2AC492303F50786758D0B4B63EEB8D031850832031FC5A43139C0CDA5EB4F0221009063F884220327718857A6897B87ED5D9F785FFC97F23BD45C84975A11DE721E",
 "status": "Verified",
 "timestamp": 1.634109209345e+12
 }, {
 "hashAlgorithm": "SHA-256",
 "logDescription": "Google 'Argon2022' log",
 "logId": "2979BEF09E393921F056739F63A577E5BE577D9C600AF8F94D5D265C255DC784",
 "origin": "Embedded in certificate",
 "signatureAlgorithm": "ECDSA",
 "signatureData": "3045022071D6D51A59CAA1764E478598AA8EE34B628C8F856B09CDB8382E090CF5D6D97D022100A8FE17E028BB6D439387721974ED3629B9CC44C90AC524B505B9B2375C75CBB9",
 "status": "Verified",
 "timestamp": 1.634109210136e+12
 }, {
 "hashAlgorithm": "SHA-256",
 "logDescription": "Sectigo 'Sabre' CT log",
 "logId": "5581D4C2169036014AEA0B9B573C53F0C0E43878702508172FA3AA1D0713D30C",
 "origin": "Embedded in certificate",
 "signatureAlgorithm": "ECDSA",
 "signatureData": "3045022015D94080264A3FCA83C0F3DE2B85A703384BB678FEBBE5408B4FF7D30BD40900022100DFBAB7992EE99420724CA35A5C2C252298B750994B0EAA98ACB22992F97D545E",
 "status": "Verified",
 "timestamp": 1.634109209393e+12
 }],
 "subjectName": "*.jd.com",
 "validFrom": 1634109205,
 "validTo": 1668410005
 },
 "securityState": "secure",
 "status": 200,
 "statusText": "",
 "timing": {
 "connectEnd": 96.834,
 "connectStart": 19.521,
 "dnsEnd": 19.521,
 "dnsStart": 0,
 "proxyEnd": -1,
 "proxyStart": -1,
 "pushEnd": 0,
 "pushStart": 0,
 "receiveHeadersEnd": 217.707,
 "requestTime": 2272960.91089,
 "sendEnd": 97.25,
 "sendStart": 97.03,
 "sslEnd": 96.829,
 "sslStart": 55.726,
 "workerFetchStart": -1,
 "workerReady": -1,
 "workerRespondWithSettled": -1,
 "workerStart": -1
 },
 "url": "https://item.m.jd.com/product/10052422060501.html"
 },
 "timestamp": 2272961.1294,
 "type": "Document"
 }
 },
 "webview": "78D9BC6F0CBE162DA6779F410AA1500C"
}

完整代码：

var option = new ChromeOptions();
option.SetLoggingPreference("performance",OpenQA.Selenium.LogLevel.Info); //启用performance日志，等级为Info即可
option.PerformanceLoggingPreferences = new ChromiumPerformanceLoggingPreferences() {
 IsCollectingNetworkEvents = true //采集网络请求事件
};
using (ChromeDriver driver = new ChromeDriver(driverPath,option,TimeSpan.FromSeconds(5))) {
 driver.Navigate().GoToUrl("https://item.m.jd.com/product/10052422060501.html");
 Thread.Sleep(3 * 1000); //等待页面加载完成
 var logs = driver.Manage().Logs.GetLog("performance").Where(o => o.Message.Contains("\"Network.responseReceived\""))；//获取所有performance日志，并过滤出所有类型为Network.responseReceived的日志
　　　foreach (var log in logs) {
　　　　　　//日志找不到就会抛出异常，必须要捕获异常
　　　　　　try {
　　　　　　　　var json = JObject.Parse(log.Message);
　　　　　　　　var url = json["message"]["params"]["response"]["url"].ToString(); //请求url，可通过url过滤出你要的请求
　　　　　　　　var requestId = json["message"]["params"]["requestId"].ToString();
　　　　　　　　//利用RequestId做为参数，执行CDP命令获取日志详细内容。 踩坑警告：返回的是一个字典，需要转换为Dictionary<string,object>
　　　　　　　　var response = driver.ExecuteCdpCommand("Network.getResponseBody",new Dictionary<string,object>() {{ "requestId",requestId }}) as Dictionary<string,object>;
　　　　　　　　if (response.TryGetValue("body",out object? bodyObj) && bodyObj != null) {
　　　　　　　　　　string body = bodyObj.ToString();
　　　　　　　　　　Console.WriteLine($"输出Body内容：{body}");
　　　　　　　　}
　　　　　　} catch(Exception ex){
　　　　　　　　//记录错误日志
　　　　　　}
　　　}
}

 封装

为了以后方便复用，我封装了一个类

其中过滤条件的入参，可以根据实际情况自行修改，如果不需要对body内容进行过滤可以去掉这个参数，这样就不用每次等待拿到结果再过滤，性能会好很多

　　 /// <summary>
 /// Selenium网络请求日志帮助类
 /// </summary>
 public class NetworkLoggingHelper
 {
 static readonly Logger logger = NlogProvider.GetLogger();
 /// <summary>
 /// 开启网络请求日志
 /// </summary>
 /// <param name="option"></param>
 public static void OpenNetworkPerformanceLogging(ref ChromeOptions option)
 {
 option.SetLoggingPreference("performance",OpenQA.Selenium.LogLevel.Info);
 option.PerformanceLoggingPreferences = new ChromiumPerformanceLoggingPreferences() {
 IsCollectingNetworkEvents = true
 };
 }
 /// <summary>
 /// 获取网络请求数据
 /// </summary>
 /// <param name="driver"></param>
 /// <param name="filter">过滤条件 入参1：请求的url | 入参2：请求的mimeType | 入参3：请求的body</param>
 /// <returns></returns>
 public static Dictionary<string,string> GetNetworkApiDatas(ChromeDriver driver,Func<string,string,string,bool> filter)
 {
 Dictionary<string,string> datas = new Dictionary<string,string>();
 try {
 var logs = driver.Manage().Logs.GetLog("performance")?.Where(o => o.Message.Contains("\"Network.responseReceived\""));
 foreach (var log in logs) {
 try {
 var json = JObject.Parse(log.Message);
 if (json["message"]["params"] == null || json["message"]["params"]["response"] == null) {
 continue;
 }
 var url = json["message"]["params"]["response"]["url"].ToString();
 var mimeType = json["message"]["params"]["response"]["mimeType"].ToString();
 var requestId = json["message"]["params"]["requestId"].ToString();
 var response = driver.ExecuteCdpCommand("Network.getResponseBody",new Dictionary<string,object>() {
 { "requestId",requestId }
 }) as Dictionary<string,object>;
 if (response != null && response.Count > 0) {
 //是否base64编码
 var isBase64Encode = false;
 if (response.TryGetValue("base64Encoded",out object? base64Encoded) && base64Encoded != null) {
 isBase64Encode = (bool)base64Encoded;
 }
 //获取响应内容
 string body = string.Empty;
 if (response.TryGetValue("body",out object? bodyObj) && bodyObj != null) {
 body = bodyObj.ToString();
 if (isBase64Encode) {
 body = body.DecodeBase64(Encoding.UTF8);
 }
 }
 //根据条件过滤，如果不需要body内容参与过滤条件判断，这个if语句可以移到获取response的上面，性能会好很多
 if (filter.Invoke(url,mimeType,body)) {
 datas.Add(url,body);
 }
 }
 } catch (Exception ex) {
 logger.Error(ex.Message);
 }
 }
 } catch (Exception ex) {
 logger.Error($"获取日志失败：{ex.Message}");
 }
 return datas;
 }
 }

调用示例：

var option = new ChromeOptions();
NetworkLoggingHelper.OpenNetworkPerformanceLogging(ref option); //开启日志
using (ChromeDriver driver = new ChromeDriver(driverPath,option,TimeSpan.FromSeconds(5))) {
 driver.Navigate().GoToUrl("https://item.m.jd.com/product/10052422060501.html");
 Thread.Sleep(3 * 1000); //等待页面加载完成
 
 var datas = NetworkLoggingHelper.GetNetworkApiDatas(driver,(url,mimeType,body) => {
 return url.Contains("//item.m.jd.com/product/") || mimeType.Contains("application/json") || body.Contains("windows.itemInfo");
 });
 Console.WriteLine(datas.Count);
}

Selenium工作原理

叙述一下selenium工作的过程

1.selenium client(python等语言编写的自动化测试脚本)初始化一个service服务，通过Webdriver启动浏览器驱动程序chromedriver.exe

2.通过RemoteWebDriver向浏览器驱动程序发送HTTP请求，浏览器驱动程序解析请求，打开浏览器，并获得sessionid，如果再次对浏览器操作需携带此id

3.打开浏览器，绑定特定的端口，把启动后的浏览器作为webdriver的remote server

3.打开浏览器后，所有的selenium的操作(访问地址，查找元素等)均通过RemoteConnection链接到remote server，然后使用execute方法调用_request方法通过urlib3向remote server发送请求

4.浏览器通过请求的内容执行对应动作

5.浏览器再把执行的动作结果通过浏览器驱动程序返回给测试脚本

6.  webdriver.是 w3c 的标准协议。提供一组接口,用于发现和操作web文档中的DOM元素。

     webdriver.是一系列的API.它给测试代码提供了定位和操作 wEB元素的能力。不同的开发语言有相应的wsbdriver.

↑↑↑↑ 该部分内容来自：https://www.cnblogs.com/xrxc/p/14776895.html

作者：Harry

原文出处：https://www.cnblogs.com/simendancer/articles/16546199.html

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