Question

如果在这个问题上花了很多时间，我发现了很多不同的策略，但是没有一个对我有用。（此代码只是课程概念的证明。）

我使用Asp.net core 2.1（在.Net Framwork 4.7.2上）具有以下设置：

我已经制作了一个信号发送器中枢，它具有一种发送号码的方法：

using System.Threading.Tasks;
using Microsoft.AspNetCore.SignalR;


namespace TestRandomNumberSignalR
{
    public class TestHub : Hub
    {
        public async Task SendRandomNumber(int number)
        {
            await Clients.All.SendAsync("ReceiveRandomBumber", number);
        }
    }
}

我还提出了一类更新的随机数每3秒，并加入它作为一个单：

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

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

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddSingleton(new UpdateRandomNumber());
            services.AddSignalR();
            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
        }

        // 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.UseMvc();
            app.UseSignalR(routes =>
            {
                routes.MapHub<TestHub>("/testHub");
            });
        }
    }
}

下面是随机数类：

using System;
using System.Threading;
using System.Threading.Tasks;

namespace TestRandomNumberSignalR
{
    public class UpdateRandomNumber
    {
        private bool _continue = true;

        public UpdateRandomNumber()
        {
            var task = new Task(() => RandomNumberLoop(),
                                TaskCreationOptions.LongRunning);
            task.Start();
        }

        private void RandomNumberLoop()
        {
            Random r = new Random();

            while (_continue)
            {
                Thread.Sleep(3000);
                int number = r.Next(0, 100);
                Console.WriteLine("The random number is now " + number);

                // Send new random number to connected subscribers here
                // Something like TestHub.SendRandomNumber(number);

            }
        }

        public void Stop()
        {
            _continue = false;
        }
    }
}

现在从此类（如我在评论中所述）开始，我想使用SignalR发送新的随机数。只有如何让枢纽背景在那里呢？

我还希望能够从控制器内部访问类的Stop（）方法，我该如何访问呢？

我现在这是一个经过充分讨论的主题，但仍然找不到任何可行的解决方案。希望你能帮助我。

编辑

问题1

虽然随机循环现在开始（非常感谢rasharasha），但仍然存在一些问题。我现在无法注射合适的UpdateRandomNumber到控制器。可以说我希望能够停止调用UpdateRandomNumber.Stop（）方法的循环，如何将UpdateRandomNumber单例注入到控制器中。我尝试创建一个界面：

public interface IUpdateRandomNumber
{
    void Stop();
}

更改RandomNumber方法以实现此目的：

public class UpdateRandomNumber : IUpdateRandomNumber
{
    private bool _continue = true;

    private IHubContext<TestHub> testHub;

    public UpdateRandomNumber(IHubContext<TestHub> testHub)        
    {
        this.testHub = testHub;

        var task = new Task(() => RandomNumberLoop(),
                            TaskCreationOptions.LongRunning);
        task.Start();
    }

    private void RandomNumberLoop()
    {
        Random r = new Random();

        while (_continue)
        {

            Thread.Sleep(3000);
            int number = r.Next(0, 100);
            Console.WriteLine("The random number is now " + number);

            // Send new random number to connected subscribers here
            // Something like TestHub.SendRandomNumber(number);

        }
    }

    public void Stop()
    {
        _continue = false;
    }
}

并更改添加单例方法，使其可以使用以下接口：

        services.AddSingleton<IUpdateRandomNumber>(provider =>
        {
            var hubContext = provider.GetService<IHubContext<TestHub>>();
            var updateRandomNumber = new UpdateRandomNumber(hubContext);
            return updateRandomNumber;
        });

我现在可以使用一种方法来创建一个控制器来停止randomnumber循环：

[Route("api/[controller]")]
[ApiController]
public class RandomController : ControllerBase
{
    private readonly IUpdateRandomNumber _updateRandomNumber;

    public RandomController(IUpdateRandomNumber updateRandomNumber)
    {
        _updateRandomNumber = updateRandomNumber;
    }

    // POST api/random
    [HttpPost]
    public void Post()
    {
        _updateRandomNumber.Stop();
    }

但是，这种实现将防止循环再次开始。那么如何从控制器访问rondomnumber单例呢？

问题2

现在可以从我的UpdateRandomNumber类调用：

testHub.Clients.All.SendAsync("ReceiveRandomBumber", number);

可是为什么我做的方法，我testhub：

    public async Task SendRandomNumber(int number)
    {
        await Clients.All.SendAsync("ReceiveRandomBumber", number);
    }

在中心中创建方法并直接调用它们会更方便。能做到吗？

Answer 1

您可以使用构造函数注入将TestHub注入控制器。由于它已经在DI容器中注册。

public class UpdateRandomNumber
{
    private bool _continue = true;
    private IHubContext<TestHub> testHub;
    private Task randomNumberTask;
    public UpdateRandomNumber(IHubContext<TestHub> testHub)
    {
        this.testHub=testHub;
        randomNumberTask = new Task(() => RandomNumberLoop(),
            TaskCreationOptions.LongRunning);
        randomNumberTask.Start();
    }
    private async void RandomNumberLoop()
    {
        Random r = new Random();

        while (_continue)
        {
            Thread.Sleep(3000);
            int number = r.Next(0, 100);
            Console.WriteLine("The random number is now " + number);

            // Send new random number to connected subscribers here
             await testHub.Clients.All.SendAsync($"ReceiveRandomNumber", number);

        }
    }

    public void Stop()
    {
        _continue = false;
    }
}
public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {

        services.AddSignalR();
        services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
        services.AddSingleton(provider =>
        {
            var hubContext = provider.GetService<IHubContext<TestHub>>();
            var updateRandomNumber = new UpdateRandomNumber(hubContext);
            return updateRandomNumber;
        });

    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        var updateRandonNumber = app.ApplicationServices.GetService<UpdateRandomNumber>();
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }

        app.UseMvc();
        app.UseSignalR(routes =>
        {
            routes.MapHub<TestHub>("/testHub");
        });
    }
}

ASP.NET核心SignalR存取权限枢纽方法在任何地方

1 个答案: