c# 通过webView2模拟登陆小红书网页版，解析无水印视频图片，以及解决X-s,X-t签名验证【2023年4月15日】

一、c# WebView2简介
1.一开始使用WebBrowser，因为WebBrowser控件使用的是ie内核，经过修改注册表切换为Edge内核后，
发现Edge内核版本较低，加载一些视频网站提示“浏览器版本过低“，”视频无法加载“。

2.WebBrowser内核版本与WebView2比较

WebBrowser内核版本：
内核版本 (Version) Edge 18.9200 兼容 WebKit 537.36 Chrome 70
UserAgent: Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.102 Safari/537.36 Edge/18.9200

当前Edge内核版本：
内核版本 (Version) WebKit 537.36 Chrome 111.0.0.0
UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/111.0.0.0 Safari/537.36 Edg/111.0.1661.54

WebView2内核版本：
内核版本 (Version) WebKit 537.36 Chrome 111.0.0.0
UserAgent:Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/111.0.0.0 Safari/537.36 Edg/111.0.1661.51

可见，WebView2内核版本跟Edge一样，能顺利打开视频网站。WebBrowser内核版本过低。

WebView2加载视频网站

3.WebView2概述
Microsoft Edge WebView2 控件允许在本机应用中嵌入 web 技术(HTML、CSS 以及 JavaScript)。 WebView2 控件使用 Microsoft Edge 作为绘制引擎，以在本机应用中显示 web 内容。
虽说无法跨平台，但是在windows应用下做为原浏览器控件替代品还是不错的。

4.安装webview2
打开NuGet，搜索WebView2，安装之后，可以看到左侧就有了webview2控件，可以直接拖到窗体内。

二、问题分析
1、关于登陆会话的问题
网页端必须打开小红书网站。小红书打开后，在浏览器Cookie里，有一个字段：
web_session=040069b3b3f6625dade26f8d1d364b44f72186
这是记录登陆会话信息的。请求时headers中需要x-s、x-t，cookie中需要有web_session。
经测试，这个web_session会在浏览器保存一段时间，具体多久还有待验证（B站也有个类似的session，是一个月）。其它字段无关紧要。
不使用WebView2打开网站的话，需要到网站申请web_session，这里WebView2已经替我们弄好了。
通过c# WebView2获取cookie信息的方法：

private Dictionary<string, string> mCookies = new Dictionary<string, string>();//保存Cookie到字典中/// <summary>/// WebView2异步获取cookie/// </summary>/// <param name="url">与cookie关联的域名</param>private async void getCookie(string url){List<CoreWebView2Cookie> cookieList = await webView.CoreWebView2.CookieManager.GetCookiesAsync(url);mCookies.Clear();for (int i = 0; i < cookieList.Count; ++i){CoreWebView2Cookie cookie = webView.CoreWebView2.CookieManager.CreateCookieWithSystemNetCookie(cookieList[i].ToSystemNetCookie());mCookies.Add(cookie.Name, cookie.Value);}}/// <summary>/// 提取cookie中的一个字段；/// </summary>/// <param name="url">域名</param>/// <param name="key">关键字，如：web_session</param>/// <param name="t">延时（没用到）</param>/// <returns></returns>public string getCookieEx(string url, string key, int t){getCookie(url);if (mCookies.ContainsKey(key)){string cookies = "";foreach (var cookie in mCookies){cookies += cookie.Key + "=" + cookie.Value + ";";}cookies = key + "=" + mCookies[key];return cookies;}return null;}

2.笔记信息接口

目前笔记信息接口： /api/sns/web/v1/feed
请求时headers中需要x-s、x-t，cookie中需要有web_session。

3.X-S
定位方法很多，可以全局搜 "X-s" 。往上找可以发现该段为 sign 方法，function sign(e, t) {}

全部复制到本地，然后根据报错把缺的方法和环境补一下，比如a0_0x4dee00、a0_0x5c27、a0_0x543e等方法，

然后把常用的navigator、location、document、window加上就好了。

该过程中根据具体错误再调试分析，比如sign方法的 case "6"，修改为var vr = window 、在case "7"中可以手动修改为 dr = ur['sNYMU']
这里已经拿到了function sign(e, t) {}的JavaScript版，需要的+v:byc6352

三、WebView2中C#和JavaScript代码互操作
1.需要创建一个ScriptHost对象，并注册到WebView2中：

    /// <summary>/// 网页调用C#方法/// </summary>[ClassInterface(ClassInterfaceType.AutoDual)][ComVisible(true)]public class ScriptHost

2.在WebView2初始化完成事件中注册ScriptHost对象

        /// <summary>/// CoreWebView2初始化完成/// </summary>/// <param name="sender"></param>/// <param name="e"></param>private void webView_CoreWebView2InitializationCompleted(object sender, CoreWebView2InitializationCompletedEventArgs e){//注册winning，winasync脚本c#互操作webView.CoreWebView2.AddHostObjectToScript("scriptHost", scriptHost);//注册全局变量winning 同步操作；winasync:异步操作；webView.CoreWebView2.AddScriptToExecuteOnDocumentCreatedAsync("var winasync= window.chrome.webview.hostObjects.scriptHost;");webView.CoreWebView2.AddScriptToExecuteOnDocumentCreatedAsync("var winning= window.chrome.webview.hostObjects.sync.scriptHost;");}

3.ScriptHost中暴露的公共方法，都可以在前端JavaScript中调用。

        /// <summary>/// 日志记录（JavaScript前端调用/// </summary>/// <param name="message">JavaScript前端信息</param>public void log(string message){Log.i(message);//记录到文本文件中//MessageBox.Show(message);}
..............................................
winning.log(data);//JavaScript端调用(同步调用)；

四、下载封面及视频


using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Configuration;
using System.Text;
using System.Threading.Tasks;namespace XhsVideo
{/// <summary>/// 下载视频/// </summary>internal class VideoDown{public int id { get; set; }public VideoInfo video { get; set; }public string savedir { get; set; }public string msg { get; set; }public bool success { get; set; }public string headers { get; set; }public VideoDown(int id,VideoInfo video,string savdir,string headers=null) {this.id = id;this.video = video;this.savedir = savdir;if (System.IO.Directory.Exists(savdir)) System.IO.Directory.CreateDirectory(savdir);this.headers = headers;}public void process(){string filename = MakeValidFileName( video.title,"");  //去除文件名中的非法字符string videoname = savedir + "\\" + filename + ".mp4";string covername = savedir + "\\" + filename + ".webp";if (System.IO.File.Exists(covername)) System.IO.File.Delete(covername);if (System.IO.File.Exists(videoname)) System.IO.File.Delete(videoname);Log.i(videoname);Log.i(covername);//NetHelper.downloadfileAsync(video.videoUrl, videoname);NetHelper.downloadfileAsync(video.coverUrl, covername);NetHelper.DownloadFileAsync(video.videoUrl, videoname, showProgress);//显示下载视频的进度}/*** @param text: 原始串* @param replacement: 要替换的字符串*/public static string MakeValidFileName(string text, string replacement = "_"){StringBuilder str = new StringBuilder();var invalidFileNameChars = System.IO.Path.GetInvalidFileNameChars();foreach (var c in text){if (invalidFileNameChars.Contains(c)){str.Append(replacement ?? "");}else{str.Append(c);}}return str.ToString();}/// <summary>/// 下载视频的进度回调函数/// </summary>/// <param name="msg">下载进度信息</param>public void showProgress(string msg){this.msg = msg;Log.i(msg);fMainForm.GetFMainForm().syncContext.Send(fMainForm.GetFMainForm().SetTextSafePost, this);//Post 将信息发送到窗体显示}}/// <summary>/// 视频信息类，由：标题，封面地址，视频地址组成。/// </summary>public class VideoInfo{public string title { get; set; }public string coverUrl { get; set; }public string videoUrl { get; set; }public VideoInfo(string title,string coverUrl,string videoUrl){this.title = title;this.coverUrl = coverUrl;this.videoUrl = videoUrl;}}
}

五、日志记录


using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;namespace XhsVideo
{/// <summary>/// 日志记录 到文本文件/// </summary>internal class Log{private static  Log log;private static string logName;private Log(string filename) {logName = filename;}public static Log GetLog(string filename){if (log == null) { log = new Log(filename); }return log;}public static Log GetLog(){return log;}public static void i(string msg){string now = DateTime.Now.ToString();string[] text = new string[2];text[0] = now;text[1] = msg;try{using (StreamWriter sw = new StreamWriter(logName,true,Encoding.UTF8)){foreach (string s in text){sw.WriteLine(s);}sw.Close();}}catch (Exception e){//Console.WriteLine("Exception: " + e.Message);}finally{//Console.WriteLine("Executing finally block.");}}}
}

六、网络访问组件


using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http.Headers;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using System.Net;
using System.IO;
using System.Windows.Forms;namespace XhsVideo
{/// <summary>/// 网络访问组件/// </summary>internal class NetHelper{#region 文件下载/// <summary>/// 下载文件/// </summary>/// <param name="url">文件下载地址</param>/// <param name="savePath">本地保存路径+名称</param>/// <param name="downloadCallBack">下载回调（总长度,已下载,进度）</param>/// <returns></returns>/// <exception cref="Exception"></exception>public static async Task DownloadFileAsync(string url, string savePath, Action<string> downloadCallBack = null){try{downloadCallBack?.Invoke($"文件【{url}】开始下载！");HttpResponseMessage response = null;using (HttpClient client = new HttpClient())response = await client.GetAsync(url);if (response == null){downloadCallBack?.Invoke("文件获取失败");return;}var total = response.Content.Headers.ContentLength ?? 0;var stream = await response.Content.ReadAsStreamAsync();var file = new FileInfo(savePath);using (var fileStream = file.Create())using (stream){if (downloadCallBack == null){await stream.CopyToAsync(fileStream);downloadCallBack?.Invoke($"文件【{url}】下载完成！");}else{byte[] buffer = new byte[1024];long readLength = 0;int length;double temp = 0;string msg = "";while ((length = await stream.ReadAsync(buffer, 0, buffer.Length)) != 0){// 写入到文件fileStream.Write(buffer, 0, length);//更新进度readLength += length;double progress = Math.Round((double)readLength / total * 100, 2, MidpointRounding.AwayFromZero);//.ToZeroif ((progress % 1) == 0 && (progress % 1) != temp){ msg = $"总大小：【{total}】，已下载：【{readLength}】,进度：【{progress}】";downloadCallBack?.Invoke(msg);}temp = progress % 1;//下载完毕立刻关闭释放文件流if (total == readLength && progress == 100){fileStream.Close();fileStream.Dispose();msg = $"总大小：【{total}】，已下载：【{readLength}】,进度：【{progress}】下载完成。";downloadCallBack?.Invoke(msg);}}}}}catch (Exception ex){downloadCallBack?.Invoke($"下载文件失败：{ex.Message}!");}}#endregion/// <summary>/// 异步下载文件/// </summary>/// <param name="url"></param>/// <param name="filename"></param>public static async void downloadfileAsync(string url,string filename){using (var web = new WebClient()){await web.DownloadFileTaskAsync(url, filename);}}/// <summary>/// 地址重定向/// </summary>/// <param name="url">原地址</param>/// <param name="domain">域名</param>/// <param name="ua">userAgent</param>/// <returns>重定向后的地址</returns>public static string getRedirectedUrl(string url, string domain, string ua){var str = getRedirectedUrl_T(url);return str.Result;}/// <summary>/// 异步地址重定向/// </summary>/// <param name="url"></param>/// <returns></returns>private static async Task<string> getRedirectedUrl_T(string url){try{var handler = new HttpClientHandler(){AllowAutoRedirect = false};var client = new HttpClient(handler);var response = await client.GetAsync(url).ConfigureAwait(continueOnCapturedContext: false);int statuscode = (int)response.StatusCode;if (statuscode == 307){string location = response.Headers.Location.ToString();return location;}if (statuscode == 302){string location = response.Headers.Location.ToString();return location;}else{return "";}}catch (Exception e){System.Diagnostics.Debug.WriteLine("getRedirectedUrl_T：" + e.ToString());return "";}}//---------------------------------------------------------------post---------------------------------------------------------------------/// <summary>/// Post访问/// </summary>/// <param name="url">访问地址</param>/// <param name="args">数据</param>/// <param name="headers">HTTP头</param>/// <returns>返回服务器JSON数据</returns>public static string getPostResult(string url, string args, string headers){var str = getPostResult_T(url, args, headers);return str.Result;}/// <summary>/// 异步post调用/// </summary>/// <param name="url"></param>/// <param name="args"></param>/// <param name="headers"></param>/// <returns></returns>private static async Task<string> getPostResult_T(string url, string args, string headers){try{var handler = new HttpClientHandler() { UseCookies = false };var client = new HttpClient(handler);// { BaseAddress = baseAddress };client.Timeout = TimeSpan.FromSeconds(20);var message = new HttpRequestMessage(HttpMethod.Post, url);message.Content = new StringContent(args);message.Content.Headers.ContentType = new MediaTypeHeaderValue("application/json");//message.Headers;Dictionary<string, string> dictionary = ParseToDictionary(headers);foreach (var pair in dictionary){if (pair.Key.Equals("content-type")) continue;if (pair.Key.Equals("Content-Type")) continue;message.Headers.Add(pair.Key, pair.Value);}var result = await client.SendAsync(message).ConfigureAwait(continueOnCapturedContext: false);result.EnsureSuccessStatusCode();return await result.Content.ReadAsStringAsync();}catch (Exception e){//EventLog.GetEventLogs(e.ToString);System.Diagnostics.Debug.WriteLine("getPostResultEx_T：" + e.ToString());///console.write(e.ToString());return "";}}/// <summary>/// 字符串解析为字典数据/// </summary>/// <param name="str">以回车换行符分割的字符串</param>/// <returns>字典数据</returns>private static Dictionary<string, string> ParseToDictionary(string str){Dictionary<string, string> result = new Dictionary<string, string>();string str1 = str;int i = str1.IndexOf("\r\n");int j = 0;while (i > 0){string str2 = str1.Substring(0, i);j = str2.IndexOf(":");if (j > 0){string str21 = str2.Substring(0, j);string str22 = str2.Substring(j + 1);result.Add(str21, str22);}str1 = str1.Substring(i + 2);i = str1.IndexOf("\r\n");}j = str1.IndexOf(":");if (j > 0){string str21 = str1.Substring(0, j);string str22 = str1.Substring(j + 1);result.Add(str21, str22);}return result;}//-------------------------------------------------------------------GET -------------------------------------------------------------------/// <summary>/// 获取服务器端的HTML代码/// </summary>/// <param name="url"></param>/// <returns></returns>public static string getHtmlCode(string url){var str = getHtmlCode_T(url);return str.Result;}/// <summary>/// 异步获取服务器端的HTML代码/// </summary>/// <param name="url"></param>/// <returns></returns>public static async Task<string> getHtmlCode_T(string url){try{var http = new HttpClient();http.Timeout = TimeSpan.FromSeconds(10);var result = await http.GetStringAsync(url).ConfigureAwait(continueOnCapturedContext: false);return result;}catch (Exception e){//EventLog.GetEventLogs(e.ToString);System.Diagnostics.Debug.WriteLine("错误信息在这儿：" + e.ToString());///console.write(e.ToString());Log.i(e.ToString());return "";}}}
}

因为涉及的技术知识点太多了，一时半会写不完，后续继续完善。需要源码的加。

(未完待续）