C# Playwright使用Cookies跳过登录报错求助

一、处理'JSON解析起始值无效'错误 #

• 问题根源：userCookies.json格式不符合Playwright要求，要么文件为空、有语法错误，要么不是标准的Cookies数组结构。
• 解决步骤：
  1. 验证文件格式：打开userCookies.json，确认是数组结构（开头[，结尾]），每个元素包含name、value、domain等必要字段，示例结构：

     [
       {"name": "session_id", "value": "abc123", "domain": ".your-site.com", "path": "/", "expires": 1720000000, "httpOnly": true, "secure": true}
     ]
     

  2. 检查文件编码：读取文件时用UTF-8编码，避免乱码导致解析失败，C#代码示例：

     var cookiesJson = File.ReadAllText("userCookies.json", Encoding.UTF8);
     

  3. 清理JS导出的冗余内容：如果是从JavaScript Playwright导出的文件，删掉可能存在的尾逗号（C# JSON序列化器不允许这种语法）。

二、处理'Microsoft.Playwright.IBrowser接口无法解析'错误 #

• 问题根源：Playwright依赖未正确安装，或者初始化Browser的方式错误。
• 解决步骤：
  1. 确认依赖安装：确保已安装Microsoft.Playwright NuGet包，并且运行过playwright install命令（安装浏览器驱动）。
  2. 正确初始化Browser：必须通过Playwright实例的浏览器类型（Chromium/Firefox/WebKit）启动，不能直接实例化IBrowser，示例代码：

     using var playwright = await Playwright.CreateAsync();
     await using var browser = await playwright.Chromium.LaunchAsync(new BrowserTypeLaunchOptions
     {
         Headless = false
     });
     

  3. 依赖注入场景：如果用DI，先注册Playwright服务，再通过构造函数注入IPlaywright和IBrowserType来启动浏览器：

     // 注册服务
     services.AddPlaywright();
     // 构造函数注入
     public YourService(IPlaywright playwright, IBrowserType browserType)
     {
         _browser = await browserType.LaunchAsync();
     }
     

完整的加载Cookies示例代码 #

using Microsoft.Playwright;
using System.Text.Json;
using System.Text;

// 初始化Playwright与浏览器
using var playwright = await Playwright.CreateAsync();
await using var browser = await playwright.Chromium.LaunchAsync(new BrowserTypeLaunchOptions
{
    Headless = false
});

// 读取并解析Cookies文件
var cookiesJson = File.ReadAllText("userCookies.json", Encoding.UTF8);
var cookies = JsonSerializer.Deserialize<List<Cookie>>(cookiesJson);

// 创建上下文并加载Cookies
var context = await browser.NewContextAsync();
await context.AddCookiesAsync(cookies);

// 打开目标页面，已自动处于登录状态
var page = await context.NewPageAsync();
await page.GotoAsync("https://your-target-site.com");

内容的提问来源于stack exchange，提问作者ramiro