SignalR不再起作用，因为升级到.NET CORE 3.1

Question

我有一个最近将.NET Core 2.1升级到3.1的WebSocket Server应用程序，但是从那时起，谈判似乎失败了。 这是我的控制台显示的错误。

我尽力在如何最好地升级到3.1。在下面的代码中，您可以找到我当前C＃服务器的所有软件包。我知道，对于3.1，您不必参考Signalr软件包，因为Microsoft.aspnetcore.app就足够了，但是我在别人的帖子上看到了它帮助了他们，所以我试图将其添加到我的身上（没有运气）。

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.App" />
    <FrameworkReference Include="Microsoft.AspNetCore.App" />
    <PackageReference Include="Microsoft.AspNetCore.SignalR.Core" Version="1.1.0" />
    <PackageReference Include="Microsoft.AspNetCore.SignalR.Client" Version="3.1.24" />
    <PackageReference Include="Microsoft.AspNetCore.Razor.Design" Version="2.1.2" PrivateAssets="All" />
    <PackageReference Include="Microsoft.VisualStudio.Azure.Containers.Tools.Targets" Version="1.0.2105168" />
    <PackageReference Include="RabbitMQ.Client" Version="5.2.0" />
    <PackageReference Include="Microsoft.AspNetCore.Mvc.NewtonsoftJson" Version="3.1.10" />
  </ItemGroup>

这是我启动类的代码：

public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }
        readonly string MyAllowSpecificOrigins = "_myAllowSpecificOrigins";

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.Configure<ConnectionOptions>(Configuration.GetSection("MQConfig"));

            services.AddHostedService<LiveUpdaterService>();

            services.AddCors(options =>
            {
                options.AddPolicy(MyAllowSpecificOrigins,
                builder =>
                {
                    builder
                    .AllowAnyMethod()
                    .AllowAnyHeader()
                    .AllowAnyOrigin()
                    .AllowCredentials();
                });
            });

            //I also tried services.AddSignalR();
            services.AddSignalRCore();  

            services.AddMvc(options => options.EnableEndpointRouting = false)
                .SetCompatibilityVersion(CompatibilityVersion.Version_3_0);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, Microsoft.AspNetCore.Hosting.IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                //app.UseHsts();
            }

            app.UseCors(cors =>
            {
                cors.AllowAnyHeader();
                cors.AllowAnyOrigin();
                cors.AllowAnyMethod();
                cors.AllowCredentials();
            });

            app.UseStaticFiles();
            
            app.UseRouting();
           
            app.UseAuthentication();
            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapHub<LiveUpdateHub>("/liveupdatehub", options =>
                {
                    options.Transports =
                        HttpTransportType.WebSockets |
                        HttpTransportType.LongPolling;
                });
                endpoints.MapControllers();
            });

            app.UseMvc();
            
        }
}

这是我的JavaScript客户端的代码：

import { HubConnectionBuilder, LogLevel } from "@microsoft/signalr";

var connection;
var connected;

export default class LiveDataHub {

    connectWebSocket() {

        connection = new HubConnectionBuilder()
            .withUrl("http://localhost:5003/liveupdatehub")
            .configureLogging(LogLevel.Information)
            .withAutomaticReconnect()
            .build();
        
        //Disable button until connection is established
        document.getElementById("runTestButton").disabled = true;
        
        connection.onclose(function (error) {
            document.getElementById("runTestButton").disabled = true;
            connected = false;
            console.log(error)
            alert("There was a problem connecting to the backend, please try again");
        });
        
        connection
            .start()
            .then(function () {
                document.getElementById("runTestButton").disabled = false;
                console.log(connection);
                connected = true;
            })
            .catch(function (err) {
                alert("No connection could be made to the backend, please refresh: " + err.toString());
                connected = false;
                return console.error(err.toString());
            });
        return connection;
    }

到目前为止，我尝试移动配置和配置方法，因为我知道它们的顺序在3.1中很重要，但是也许有一个位置i弗错过了。我还尝试了添加很多额外的配置方法，这些方法是从其他帖子中读取的，例如（options =＆gt; options.enabledpointreting = false）或addNewtonsoftjson（）。

对于客户，我尝试通过添加以下添加来跳过谈判部分：

connectWebSocket() {
        
        connection = new HubConnectionBuilder()
            .withUrl("ws://localhost:5003/liveupdatehub", {
                    skipNegotiation: true,
                    transport: HttpTransportType.WebSockets
                  })
            .configureLogging(LogLevel.Information)
            .withAutomaticReconnect()
            .build();

，但是控制台错误日志，然后更改为这是这使我相信Signalr是这里的主要问题。

如果有人能帮助我，我将非常感谢！

Answer 1

因此，一段时间后，我发现了基本问题是什么。事实证明，呼叫services.addhostedService（）会导致托管服务在建立SignalR连接之前被调用，并且因为我的LiveUpDaterService依赖Signalr依赖Signalr，所以它崩溃了整个连接。

在评论了该方法之后，谈判与我的其余应用程序（除了LiveUpDaterService）一起工作。如果有人有兴趣，我通过此链接找到了答案： https://github.com/ azure/azure-signalr/essugn/909 。我目前正在尝试为此找到解决方法，但是至少该连接现在正在起作用。

我将其标记为解决，因为AddhostedService更像是一个兼容性问题。希望这可以帮助其他人遇到同样的问题。

我的启动的最终代码：

public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }
        readonly string MyAllowSpecificOrigins = "_myAllowSpecificOrigins";

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddRazorPages();
            services.AddSignalR();
            
            services.Configure<ConnectionOptions>(Configuration.GetSection("MQConfig"));
            services.AddCors(options =>
            {
                options.AddPolicy("AllowSetOrigins",
                builder =>
                {
                    builder
                    .AllowAnyHeader()
                    .AllowAnyMethod()
                    .AllowCredentials()
                    .WithOrigins("http://localhost:5003")
                    .WithOrigins("http://localhost:8080");
                });
            });
            //services.AddHostedService<LiveUpdaterService>();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                // 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.UseHttpsRedirection();
            app.UseStaticFiles();

            app.UseRouting();
            app.UseCors("AllowSetOrigins");
            app.UseAuthorization();
            app.UseAuthentication();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapRazorPages();
                endpoints.MapHub<LiveUpdateHub>("/liveupdatehub");
            });
        }
    }

我的软件包的最终代码：

<ItemGroup>
  <FrameworkReference Include="Microsoft.AspNetCore.App" />
  <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
  <PackageReference Include="RabbitMQ.Client" Version="5.2.0" />
</ItemGroup>