netcore mvc 的简单实现

• 实现的功能

  • 简单的路由系统
  • 支持中间件
  • 简单Filter支持
  • 只支持HttpPost、HttpGet
  • 使用Dotliquid做为视图渲染引擎

• 核心实现

  • HttpChannel

    • 复制监听Tcp请求，并按照Http协议将tcp数据传输解析为HttpRequest数据实例，解析完调用HttpHandler继续下一步处理

  • HttpRequest

    • 单次Http请求信息，包含 HttpMethod、Version、Url、HttpHeader、Cookies等信息

  • HttpResponse

    • Http响应信息

  • DefaultHttpHandler

    • 实现IHttpHandler，负责Middleware责任链的创建、执行

    •   private IMiddleware BuildMiddlewareChain()
        {
            var builder = new MiddlewareChainBuilder();
            builder.Use(new StaticFileMiddleware());
            builder.Use(new MvcMiddleware(route));
            return builder.Build();
        }
      
        public async Task<HttpResponse> ProcessAsync(HttpRequest httpRequest)
        {
            var chain = BuildMiddlewareChain();
            return await chain.Invoke(httpRequest);
        }
      

  • MvcMiddleware

    • 内置的中间件，mvc功能具体实现[FIlter模式实现]

    • public override async Task<HttpResponse> Invoke(HttpRequest httpRequest)
      {
          try
          {
              var context = new ActionExecuteContext
              {
                  HttpRequest = httpRequest
              };
      
              var (controller, methodInfo, parameter) = route.Route(httpRequest);
              if (controller == null)
              {
                  return await HttpResponseHelper.CreateNotFoundResponseAsync();
              }
      
              context.Controller = controller;
              context.Action = methodInfo;
              ((ControllerBase)controller).Request = httpRequest;
      
              var filterList = GetFilters(controller, methodInfo);
              var stack = new Stack<IFilter>();
              for (var i = 0; i < filterList.Count; i++)
              {
                  var filter = filterList[i];
                  await filter.OnActionExecutingAsync(context);
                  if (context.Final)
                  {
                      return context.HttpResponse;
                  }
                  stack.Push(filter);
              }
      
              await controller.OnActionExecutingAsync(context);
      
              if (context.Final)
              {
                  return context.HttpResponse;
              }
      
              var parameters = new List<object>();
              if (parameter != null)
              {
                  parameters.Add(parameter);
              }
      
              if (methodInfo.ReturnType.IsGenericType) //Task<IActionResult>
              {
                  var actionResult = await (methodInfo.Invoke(controller, parameters.ToArray()) as Task<IActionResult>);
                  context.HttpResponse = await actionResult.ExecuteResultAsync();
              }
              else
              {
                  var actionResult = methodInfo.Invoke(controller, parameters.ToArray()) as IActionResult;
                  context.HttpResponse = await actionResult.ExecuteResultAsync();
              }
      
              context.HttpResponse.Cookies.AddRange(controller.ResponseCookie);
      
              await controller.OnActionExecutedAsync(context);
      
              if (context.Final)
              {
                  return context.HttpResponse;
              }
      
              while (stack.Count != 0)
              {
                  var filter = stack.Pop();
                  await filter.OnActionExecutedAsync(context);
      
                  if (context.Final)
                  {
                      return context.HttpResponse;
                  }
              }
              return context.HttpResponse;
          }
          catch (Exception e)
          {
              return await HttpResponseHelper.CreateDefaultErrorResponseAsync(e);
          }
      }
      

  • EasyRoute

    • 实现最简单的路由解析【URL---> IController/Method】

    • Controller实例化使用netcore自带的IOC框架实现

    • public (IController, MethodInfo, object) Route(HttpRequest request)
      {
          var path = request.AbsolutePath;
          Type controllerType;
          MethodInfo methodInfo;
          switch (request.HttpMethod)
          {
              case HttpMethod.Get:
                  if (httpGetRoutes.ContainsKey(path))
                  {
                      (controllerType, methodInfo) = httpGetRoutes[path];
                  }
                  else
                  {
                      return (null, null, null);
                  }
                  break;
              case HttpMethod.Post:
                  if (httpPostRoutes.ContainsKey(path))
                  {
                      (controllerType, methodInfo) = httpPostRoutes[path];
                  }
                  else
                  {
                      return (null, null, null);
                  }
                  break;
              default://Unsupport httpmethod
                  return (null, null, null);
          }
          var controllerObj = ServiceLocator.Instance.GetService(controllerType) as IController;
          //var controllerObj = Activator.CreateInstance(controllerType) as IController;
          object parameter = null;
          var parameterType = methodInfo.GetParameters().SingleOrDefault()?.ParameterType;
          if (parameterType != null)
          {
              parameter = ResolveParameter(parameterType, request);
          }
      
          return (controllerObj, methodInfo, parameter);
      }
      

  • IActionResult

    • 执行结果的抽象，类比MVC的IActionResult

    • 内置类型

      • HttpStatusCodeResult：只返回特定StatusCode，没有具体内容

      • JsonResult：返回JSON结果，content-type：application/json

      • RedirectResult：返回302

      • ViewResult：使用DotLiquid作为视图渲染引擎

        public async Task<HttpResponse> ExecuteResultAsync()
        {
            var absoluteName = $"Views/{ViewName}";
            Template template;
            if (viewCache.ContainsKey(absoluteName))
            {
                template = viewCache[absoluteName];
            }
            else
            {
                var templateStr = Template.FileSystem.ReadTemplateFile(new Context(CultureInfo.CurrentCulture), absoluteName);
                template = Template.Parse(templateStr);
                viewCache.Add(absoluteName, template);
            }
            var content = template.Render(Hash.FromAnonymousObject(ViewData));
        
            var res = new HttpResponse();
        
            await res.WriteBodyAsync(Constants.DefaultEncoding.GetBytes(content));
        
            return res;
        }
        

  • IController

    • mvc控制器接口

  • HttpCookie

    • cookie操作类

  • IFilter

    • 过滤器接口

       public interface IFilter
       {
           int Order { get; set; }
           Task OnActionExecutingAsync(ActionExecuteContext context);
           Task OnActionExecutedAsync(ActionExecuteContext context);
       }
      

• 其他

  • 本项目只为学习使用，如有错误，请指出
  • 本项目为另一个项目 EasyProxy 的附属产物，所以没有独立的github仓库，具体目录为 HttpServer