ASP.NET Core MVC如何实现运行时动态定义Controller类型_实用技巧_

 public interface ICompiler { Assembly Compile(string text, params Assembly[] referencedAssemblies); }

 public class Compiler : ICompiler { public Assembly Compile(string text, params Assembly[] referencedAssemblies) { var references = referencedAssemblies.Select(it => MetadataReference.CreateFromFile(it.Location)); var options = new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary); var assemblyName = "_" + Guid.NewGuid().ToString("D"); var syntaxTrees = new SyntaxTree[] { CSharpSyntaxTree.ParseText(text) }; var compilation = CSharpCompilation.Create(assemblyName, syntaxTrees, references, options); using var stream = new MemoryStream(); var compilationResult = compilation.Emit(stream); if (compilationResult.Success) { stream.Seek(0, SeekOrigin.Begin); return Assembly.Load(stream.ToArray()); } throw new InvalidOperationException("Compilation error"); } }

 internal static class ControllerActionDescriptorBuilder { public static IList Build(ApplicationModel application); }

 internal class ApplicationModelFactory { public ApplicationModel CreateApplicationModel(IEnumerable controllerTypes); }

 public class DynamicActionProvider : IActionDescriptorProvider { private readonly List _actions; private readonly Func> _creator; public DynamicActionProvider(IServiceProvider serviceProvider, ICompiler compiler) { _actions = new List(); _creator = CreateActionDescrptors; IEnumerable CreateActionDescrptors(string sourceCode) { var assembly = compiler.Compile(sourceCode, Assembly.Load(new AssemblyName("System.Runtime")), typeof(object).Assembly, typeof(ControllerBase).Assembly, typeof(Controller).Assembly); var controllerTypes = assembly.GetTypes().Where(it => IsController(it)); var applicationModel = CreateApplicationModel(controllerTypes); assembly = Assembly.Load(new AssemblyName("Microsoft.AspNetCore.Mvc.Core")); var typeName = "Microsoft.AspNetCore.Mvc.ApplicationModels.ControllerActionDescriptorBuilder"; var controllerBuilderType = assembly.GetTypes().Single(it => it.FullName == typeName); var buildMethod = controllerBuilderType.GetMethod("Build", BindingFlags.Static | BindingFlags.Public); return (IEnumerable)buildMethod.Invoke(null, new object[] { applicationModel }); } ApplicationModel CreateApplicationModel(IEnumerable controllerTypes) { var assembly = Assembly.Load(new AssemblyName("Microsoft.AspNetCore.Mvc.Core")); var typeName = "Microsoft.AspNetCore.Mvc.ApplicationModels.ApplicationModelFactory"; var factoryType = assembly.GetTypes().Single(it => it.FullName == typeName); var factory = serviceProvider.GetService(factoryType); var method = factoryType.GetMethod("CreateApplicationModel"); var typeInfos = controllerTypes.Select(it => it.GetTypeInfo()); return (ApplicationModel)method.Invoke(factory, new object[] { typeInfos }); } bool IsController(Type typeInfo) { if (!typeInfo.IsClass) return false; if (typeInfo.IsAbstract) return false; if (!typeInfo.IsPublic) return false; if (typeInfo.ContainsGenericParameters) return false; if (typeInfo.IsDefined(typeof(NonControllerAttribute))) return false; if (!typeInfo.Name.EndsWith("Controller", StringComparison.OrdinalIgnoreCase) && !typeInfo.IsDefined(typeof(ControllerAttribute))) return false; return true; } } public int Order => -100; public void OnProvidersExecuted(ActionDescriptorProviderContext context) { } public void OnProvidersExecuting(ActionDescriptorProviderContext context) { foreach (var action in _actions) { context.Results.Add(action); } } public void AddControllers(string sourceCode) => _actions.AddRange(_creator(sourceCode)); }

 public class DynamicChangeTokenProvider : IActionDescriptorChangeProvider { private CancellationTokenSource _source; private CancellationChangeToken _token; public DynamicChangeTokenProvider() { _source = new CancellationTokenSource(); _token = new CancellationChangeToken(_source.Token); } public IChangeToken GetChangeToken() => _token; public void NotifyChanges() { var old = Interlocked.Exchange(ref _source, new CancellationTokenSource()); _token = new CancellationChangeToken(_source.Token); old.Cancel(); } }

 public class Program { public static void Main() { Host.CreateDefaultBuilder() .ConfigureWebHostDefaults(web => web .ConfigureServices(svcs => svcs .AddSingleton() .AddSingleton() .AddSingleton() .AddSingleton(provider => provider.GetRequiredService()) .AddSingleton(provider => provider.GetRequiredService()) .AddRouting().AddControllersWithViews()) .Configure(app => app .UseRouting() .UseEndpoints(endpoints => endpoints.MapControllerRoute( name: default, pattern: "{controller}/{action}" )))) .Build() .Run(); } }

 public class HomeController : Controller { [HttpGet("/")] public IActionResult Index() => View(); [HttpPost("/")] public IActionResult Index( string source, [FromServices]DynamicActionProvider actionProvider, [FromServices] DynamicChangeTokenProvider tokenProvider) { try { actionProvider.AddControllers(source); tokenProvider.NotifyChanges(); return Content("OK"); } catch (Exception ex) { return Content(ex.Message); } } }

Define your controller here...
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