HttpContext.Session is null in ASP.NET Core 2.2

Question

您好，我正在尝试将.Net Framework 4.6应用程序迁移到 asp.net 核心2.2，并且我无法使用HttpContext.Session。

我可以调用 SetString 方法，但在第二个请求中，GetString 始终返回空值。

我尝试了在 Stackoverflow 和官方文档上找到的不同答案，但没有一个适用于我的情况

    public void ConfigureServices(IServiceCollection services)
    {
        var appConfiguration = new AppConfigurationManager(Configuration);
        var allowedOrigins = appConfiguration.AllowedOrigins.Split(',').Select(s => s.Trim()).ToArray();
        services.AddSingleton(Configuration); // Config
        services.AddCors(o => o.AddPolicy("default", builder =>
        {
            builder.WithOrigins(allowedOrigins)
                   .AllowAnyMethod()
                   .AllowAnyHeader()
                   .AllowCredentials();
        })); // CORS
        TokenVerifier.ControlToken(services, "secretToken");
        services.AddSignalR();
        services.Configure<CookiePolicyOptions>(options =>
        {
            // This lambda determines whether user consent for non-essential cookies is needed for a given request.
            options.CheckConsentNeeded = context => false;
            options.MinimumSameSitePolicy = SameSiteMode.None;
        });
        services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
        services.AddDistributedMemoryCache();
        services.AddMvc().AddSessionStateTempDataProvider();
        services.AddSession(options =>
        {
            options.Cookie.Name = "MySession";
            options.IdleTimeout = TimeSpan.FromDays(1);
        });
        services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>(); 
        ...
    }
    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
            app.UseDatabaseErrorPage();
        }
        else
        {
            // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
            app.UseHsts();
        }
        app.UseCors("default");
        //app.UseHttpsRedirection();
        app.UseAuthentication();
        app.UseSignalR(routes =>
        {
            routes.MapHub<MindHub>("/myapp");
        });
        app.UseMiddleware<ExceptionMiddleware>();
        app.UseSession();
        app.UseMvc();
    }

请注意，JWT 身份验证、CORS 和 Signalr 正在工作(可能对你们中的一些人有所帮助(

Answer 1

这是我的最终工作示例代码，可能对你们中的一些人有用。

注意比顺序非常重要。

    // This method gets called by the runtime. Use this method to add services to the container.
    // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
    public void ConfigureServices(IServiceCollection services)
    {
        string[] allowedOrigins = new string[]; // put your allowed origins here
        services.AddSingleton(Configuration); // Config
        services.AddCors(o => o.AddPolicy("default", builder =>
        {
            builder.WithOrigins(allowedOrigins)
                   .AllowAnyMethod()
                   .AllowAnyHeader()
                   .AllowCredentials();
        }));
        TokenVerifier.ControlToken(services, "secretToken");
        services.AddSignalR();
        services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
        services.Configure<FormOptions>(x =>
        {
            x.ValueLengthLimit = int.MaxValue;
            x.MultipartBodyLengthLimit = long.MaxValue; // In case of multipart
        });
        services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>(); // HttpContext into ASP.NET Core
        // Register your stuff here
    }
    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
            app.UseDatabaseErrorPage();
        }
        else
        {
            // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
            app.UseHsts();
        }
        app.UseCors("default");
        app.UseAuthentication();
        app.UseSignalR(routes =>
        {
            routes.MapHub<YourHub>("/hubName");
        });
        app.UseMiddleware<ExceptionMiddleware>();
        app.UseHttpsRedirection();
        app.UseMvc();
    }