public void ConfigureServices(IServiceCollection services)
{
    services.AddCors(options =>
    {
        options.AddPolicy("CorsPolicy", builder => builder
            .WithOrigins("http://example.com") // 允许的源
            .AllowAnyMethod()
            .AllowAnyHeader()
            .AllowCredentials()); // 允许凭据
    });
    
    services.AddSignalR();
}

public void Configure(IApplicationBuilder app)
{
    app.UseCors("CorsPolicy");
    app.UseSignalR(routes =>
    {
        routes.MapHub<ChatHub>("/chatHub");
    });
}

// Startup.cs
services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
    .AddCookie(options =>
    {
        options.Cookie.HttpOnly = true;
        options.Cookie.SecurePolicy = CookieSecurePolicy.Always;
    });

// 在 Hub 中使用
[Authorize]
public class ChatHub : Hub
{
    public async Task SendMessage(string user, string message)
    {
        await Clients.All.SendAsync("ReceiveMessage", user, message);
    }
}

// Startup.cs
services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
    .AddJwtBearer(options =>
    {
        options.TokenValidationParameters = new TokenValidationParameters
        {
            ValidateIssuer = true,
            ValidateAudience = true,
            ValidateLifetime = true,
            ValidateIssuerSigningKey = true,
            ValidIssuer = Configuration["Jwt:Issuer"],
            ValidAudience = Configuration["Jwt:Audience"],
            IssuerSigningKey = new SymmetricSecurityKey(
                Encoding.UTF8.GetBytes(Configuration["Jwt:Key"]))
        };
        
        // SignalR 的 JWT 配置
        options.Events = new JwtBearerEvents
        {
            OnMessageReceived = context =>
            {
                var accessToken = context.Request.Query["access_token"];
                var path = context.HttpContext.Request.Path;
                if (!string.IsNullOrEmpty(accessToken) && 
                    path.StartsWithSegments("/chatHub"))
                {
                    context.Token = accessToken;
                }
                return Task.CompletedTask;
            }
        };
    });

const connection = new signalR.HubConnectionBuilder()
    .withUrl("http://yourdomain.com/chatHub", {
        accessTokenFactory: () => {
            // 返回你的 token (从 cookie 或 localStorage 获取)
            return localStorage.getItem('token');
        },
        transport: signalR.HttpTransportType.WebSockets
    })
    .configureLogging(signalR.LogLevel.Information)
    .build();

connection.start().then(() => {
    console.log("连接成功");
}).catch(err => {
    console.error(err.toString());
});