ASP.Net Core 在运行时注册控制器 [英] ASP.Net Core register Controller at runtime

问题描述

我在问自己是否可以在运行时加载带有 Controller 的 DLL 并使用它.

I am asking myself if it is possible to load a DLL with Controllers in it at runtime and use it.

我发现的唯一解决方案是通过 ApplicationPart 在 StartUp 上添加程序集:

The only solution I've found is to add an assembly via ApplicationPart on the StartUp:

var builder = services.AddMvc();
builder.AddApplicationPart(
    AssemblyLoadContext.Default.LoadFromAssemblyPath(
        @"PATHExternalControllers.dll"
));

有谁知道是否可以随时注册Controller，因为该解决方案的问题是，您必须在需要时重新启动WebService添加另一个带有 Controller 的 DLL.如果您可以随时添加它们并在应用程序中随时注册它们，那就太好了.

Do anyone know if it is possible to register Controller at any time, because the issue with that solution is, that you have to restart the WebService when you want to add another DLL with Controllers in it. It would be nice when you just can add them at any time and register them at any time in the application.

推荐答案

现在可以在 .net core 2.0+ 上实现

This is possible now on .net core 2.0+

请看代码 ActionDescriptorCollectionProvider.cs:

    public ActionDescriptorCollectionProvider(
        IEnumerable<IActionDescriptorProvider> actionDescriptorProviders,
        IEnumerable<IActionDescriptorChangeProvider> actionDescriptorChangeProviders)
    {
        _actionDescriptorProviders = actionDescriptorProviders
            .OrderBy(p => p.Order)
            .ToArray();

        _actionDescriptorChangeProviders = actionDescriptorChangeProviders.ToArray();

        ChangeToken.OnChange(
            GetCompositeChangeToken,
            UpdateCollection);
    }

第 1 步:实施 IActionDescriptorChangeProvider 类:

Step 1:Implement IActionDescriptorChangeProvider class:

public class MyActionDescriptorChangeProvider : IActionDescriptorChangeProvider
{
    public static MyActionDescriptorChangeProvider Instance { get; } = new MyActionDescriptorChangeProvider();

    public CancellationTokenSource TokenSource { get; private set; }

    public bool HasChanged { get; set; }

    public IChangeToken GetChangeToken()
    {
        TokenSource = new CancellationTokenSource();
        return new CancellationChangeToken(TokenSource.Token);
    }
}

第 2 步:在 Startup.ConfigureServices() 上添加单例:

Step 2:AddSingleton on Startup.ConfigureServices():

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc();
    services.AddSingleton<IActionDescriptorChangeProvider>(MyActionDescriptorChangeProvider.Instance);
    services.AddSingleton(MyActionDescriptorChangeProvider.Instance);
}

第 3 步:在运行时注册控制器:

Step 3: Register controller at runtime:

public class TestController : Controller
{
    private readonly ApplicationPartManager _partManager;
    private readonly IHostingEnvironment _hostingEnvironment;
    public TestController(
        ApplicationPartManager partManager,
        IHostingEnvironment env)
    {
        _partManager = partManager;
        _hostingEnvironment = env;
    }
    public IActionResult RegisterControllerAtRuntime()
    {
        string assemblyPath = @"PATHExternalControllers.dll";
        var assembly = AssemblyLoadContext.Default.LoadFromAssemblyPath(assemblyPath);
        if (assembly != null)
        {
            _partManager.ApplicationParts.Add(new AssemblyPart(assembly));
            // Notify change
            MyActionDescriptorChangeProvider.Instance.HasChanged = true;
            MyActionDescriptorChangeProvider.Instance.TokenSource.Cancel();
            return Content("1");
        }
        return Content("0");
    }
}

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