GO自研微服务框架-中间件

一.中间件

中间件的作用是给应用添加一些额外的功能，但是并不会影响原有应用的编码方式，想用的时候直接添加，不想用可以很轻松的去除，做到所谓的可插拔。

中间件的实现位置在哪里？

1. 不能耦合在用户的代码中
2. 需要独立存在，但又能拿到上下文，并能做出影响

位置：在处理器的前后

注意：中间件是一个调用链条，所以在处理真正的业务之前，可能会经过多个中间件

1. 定义中间件

type MiddlewareFunc func(handleFunc HandleFunc)HandleFunc

中间件的执行，定义为组级别。

type routerGroup struct {
	name             string
	handleFuncMap    map[string]map[string]HandleFunc
	handlerMethodMap map[string][]string
	treeNode         *treeNode
	preMiddlewares   []MiddlewareFunc //前置中间件
	postMiddlewares  []MiddlewareFunc //后置中间件
}

2. 通用前置中间件

func (r *routerGroup) PreHandle(middlewareFunc ...MiddlewareFunc) {
	r.preMiddlewares = append(r.preMiddlewares, middlewareFunc...)
}

func (r *routerGroup) methodHandle(h HandleFunc, ctx *Context) {
	//前置中间件
	if r.preMiddlewares != nil {
		for _, middlewareFunc := range r.preMiddlewares {
			h = middlewareFunc(h)
		}
	}
	h(ctx)
	//后置中间件
	for _, middlewareFunc := range r.preMiddlewares {
		h = middlewareFunc(h)
	}
}

func (e *Engine) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	e.httpRquestHandler(w, r)
}
func (e *Engine) httpRquestHandler(w http.ResponseWriter, r *http.Request) {
	method := r.Method
	for _, group := range e.routerGroups {
		routerName := SubStringLast(r.RequestURI, "/"+group.name)
		// get/1
		node := group.treeNode.Get(routerName)
		if node != nil && node.isEnd {
			//路由匹配上了
			ctx := &Context{
				W: w,
				R: r,
			}
			handle, ok := group.handleFuncMap[node.routerName][ANY]
			if ok {
				group.methodHandle(handle, ctx)
				handle(ctx)
				return
			}

			handle, ok = group.handleFuncMap[node.routerName][method]
			if ok {
				group.methodHandle(handle, ctx)
				return
			}
			//method 进行匹配
			w.WriteHeader(http.StatusMethodNotAllowed)
			fmt.Fprintf(w, "%s %s not allow\n", r.RequestURI, method)
			return
		}
	}
	w.WriteHeader(http.StatusNotFound)
	fmt.Fprintf(w, "%s not found\n", r.RequestURI)
}

3. 通用后置中间件

func (r *routerGroup) PostHandle(middlewareFunc ...MiddlewareFunc) {
	r.postMiddlewares = append(r.postMiddlewares, middlewareFunc...)
}

func (r *routerGroup) methodHandle(h HandleFunc, ctx *Context) {
	//前置中间件
	if r.preMiddlewares != nil {
		for _, middlewareFunc := range r.preMiddlewares {
			h = middlewareFunc(h)
		}
	}
	h(ctx)
	//后置中间件
	if r.postMiddlewares != nil {
		for _, middlewareFunc := range r.postMiddlewares {
			h = middlewareFunc(h)
		}
	}
	h(ctx)
}

4. 测试

func main() {
	engine := msgo.New()
	g := engine.Group("user")
	//g.Get("/hello", func(ctx *msgo.Context) {
	//	fmt.Fprintf(ctx.W, "%s Get欢迎学习GO自研框架", "lisus2000")
	//})
	g.PreHandle(func(next msgo.HandleFunc) msgo.HandleFunc {
		return func(ctx *msgo.Context) {
			fmt.Println("pre Handle")
			next(ctx)
		}
	})
	g.PostHandle(func(handleFunc msgo.HandleFunc) msgo.HandleFunc {
		return func(ctx *msgo.Context) {
			fmt.Println("post handle")
		}
	})
	g.Get("/hello/get", func(ctx *msgo.Context) {
		fmt.Fprintf(ctx.W, "%s Get欢迎学习GO自研框架", "lisus2000")
	})
	g.Post("/hello", func(ctx *msgo.Context) {
		fmt.Fprintf(ctx.W, "%s Post欢迎学习GO自研框架", "lisus2000")
	})
	g.Post("/info", func(ctx *msgo.Context) {
		fmt.Fprintf(ctx.W, "%s info功能", "lisus2000")
	})
	g.Get("/get/:id", func(ctx *msgo.Context) {
		fmt.Fprintf(ctx.W, "%s get user 路径变量的值", "lisus2000")
	})
	engine.Run()
}

5. 改造后置中间件

中间件的触发是等待用户处理函数的执行，也就是说前置中间件就可以完成后置中间件的功能，所以这里我们去除后置中间件

// 定义路由分组结构
type routerGroup struct {
	name             string
	handleFuncMap    map[string]map[string]HandleFunc
	handlerMethodMap map[string][]string
	treeNode         *treeNode
	middlewares      []MiddlewareFunc
}

func (r *routerGroup) Use(middlewareFunc ...MiddlewareFunc) {
	r.middlewares = append(r.middlewares, middlewareFunc...)
}

func (r *routerGroup) methodHandle(h HandleFunc, ctx *Context) {
   //前置中间件
   if r.middlewares != nil {
      for _, middlewareFunc := range r.middlewares {
         h = middlewareFunc(h)
      }
   }
   h(ctx)
}

测试代码

func main() {
   engine := msgo.New()
   g := engine.Group("user")
   //g.Get("/hello", func(ctx *msgo.Context) {
   // fmt.Fprintf(ctx.W, "%s Get欢迎学习GO自研框架", "lisus2000")
   //})
   g.Use(func(next msgo.HandleFunc) msgo.HandleFunc {
      return func(ctx *msgo.Context) {
         fmt.Println("pre Handle")
         next(ctx)
         fmt.Println("post Handler")
      }
   })
   g.Get("/hello/get", func(ctx *msgo.Context) {
      fmt.Fprintf(ctx.W, "%s Get欢迎学习GO自研框架", "lisus2000")
   })
   g.Post("/hello", func(ctx *msgo.Context) {
      fmt.Fprintf(ctx.W, "%s Post欢迎学习GO自研框架", "lisus2000")
   })
   g.Post("/info", func(ctx *msgo.Context) {
      fmt.Fprintf(ctx.W, "%s info功能", "lisus2000")
   })
   g.Get("/get/:id", func(ctx *msgo.Context) {
      fmt.Fprintf(ctx.W, "%s get user 路径变量的值", "lisus2000")
   })
   engine.Run()
}

6. 路由级别中间件

func (r *routerGroup) methodHandle(name string, mehtod string, h HandleFunc, ctx *Context) {
	//组通用中间件
	if r.middlewares != nil {
		for _, middlewareFunc := range r.middlewares {
			h = middlewareFunc(h)
		}
	}
	//路由级别中间件
	middlewareFuncs := r.middlewaresFuncMap[name][mehtod]
	if middlewareFuncs != nil {
		for _, middlewareFunc := range middlewareFuncs {
			h = middlewareFunc(h)
		}
	}
	h(ctx)
}

func (r *routerGroup) handle(name string, method string, handleFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
	_, ok := r.handleFuncMap[name]
	if !ok {
		r.handleFuncMap[name] = make(map[string]HandleFunc)
		r.middlewaresFuncMap[name] = make(map[string][]MiddlewareFunc)
	}
	_, ok = r.handleFuncMap[name][method]
	if ok {
		panic("有重复的路由")
	}
	r.handleFuncMap[name][method] = handleFunc
	r.middlewaresFuncMap[name][method] = append(r.middlewaresFuncMap[name][method], middlewareFunc...)
	r.treeNode.Put(name)
}

func (r *routerGroup) Any(name string, handleFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
	r.handle(name, ANY, handleFunc, middlewareFunc...)
}
func (r *routerGroup) Get(name string, handleFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
	r.handle(name, http.MethodGet, handleFunc, middlewareFunc...)
}
func (r *routerGroup) Post(name string, handleFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
	r.handle(name, http.MethodPost, handleFunc, middlewareFunc...)
}
func (r *routerGroup) Delete(name string, handlerFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
	r.handle(name, http.MethodDelete, handlerFunc, middlewareFunc...)
}
func (r *routerGroup) Put(name string, handlerFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
	r.handle(name, http.MethodPut, handlerFunc, middlewareFunc...)
}
func (r *routerGroup) Patch(name string, handlerFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
	r.handle(name, http.MethodPatch, handlerFunc, middlewareFunc...)
}
func (r *routerGroup) Options(name string, handlerFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
	r.handle(name, http.MethodOptions, handlerFunc, middlewareFunc...)
}
func (r *routerGroup) Head(name string, handlerFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
	r.handle(name, http.MethodHead, handlerFunc, middlewareFunc...)
}

完整代码如下：

package msgo

import (
   "fmt"
   "log"
   "net/http"
)

const ANY = "ANY"

type HandleFunc func(ctx *Context)

type MiddlewareFunc func(handleFunc HandleFunc) HandleFunc

// 定义路由分组结构
type routerGroup struct {
   name               string
   handleFuncMap      map[string]map[string]HandleFunc
   middlewaresFuncMap map[string]map[string][]MiddlewareFunc
   handlerMethodMap   map[string][]string
   treeNode           *treeNode
   middlewares        []MiddlewareFunc
}

type router struct {
   routerGroups []*routerGroup
}

// Group 分组方法
func (r *router) Group(name string) *routerGroup {
   routerGroup := &routerGroup{
      name:               name,
      handleFuncMap:      make(map[string]map[string]HandleFunc),
      middlewaresFuncMap: make(map[string]map[string][]MiddlewareFunc),
      handlerMethodMap:   make(map[string][]string),
      treeNode:           &treeNode{name: "/", children: make([]*treeNode, 0)},
   }
   r.routerGroups = append(r.routerGroups, routerGroup)
   return routerGroup
}

func (r *routerGroup) Use(middlewareFunc ...MiddlewareFunc) {
   r.middlewares = append(r.middlewares, middlewareFunc...)
}

func (r *routerGroup) methodHandle(name string, mehtod string, h HandleFunc, ctx *Context) {
   //组通用中间件
   if r.middlewares != nil {
      for _, middlewareFunc := range r.middlewares {
         h = middlewareFunc(h)
      }
   }
   //路由级别中间件
   middlewareFuncs := r.middlewaresFuncMap[name][mehtod]
   if middlewareFuncs != nil {
      for _, middlewareFunc := range middlewareFuncs {
         h = middlewareFunc(h)
      }
   }
   h(ctx)
}

func (r *routerGroup) handle(name string, method string, handleFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
   _, ok := r.handleFuncMap[name]
   if !ok {
      r.handleFuncMap[name] = make(map[string]HandleFunc)
      r.middlewaresFuncMap[name] = make(map[string][]MiddlewareFunc)
   }
   _, ok = r.handleFuncMap[name][method]
   if ok {
      panic("有重复的路由")
   }
   r.handleFuncMap[name][method] = handleFunc
   r.middlewaresFuncMap[name][method] = append(r.middlewaresFuncMap[name][method], middlewareFunc...)
   r.treeNode.Put(name)
}

func (r *routerGroup) Any(name string, handleFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
   r.handle(name, ANY, handleFunc, middlewareFunc...)
}
func (r *routerGroup) Get(name string, handleFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
   r.handle(name, http.MethodGet, handleFunc, middlewareFunc...)
}
func (r *routerGroup) Post(name string, handleFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
   r.handle(name, http.MethodPost, handleFunc, middlewareFunc...)
}
func (r *routerGroup) Delete(name string, handlerFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
   r.handle(name, http.MethodDelete, handlerFunc, middlewareFunc...)
}
func (r *routerGroup) Put(name string, handlerFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
   r.handle(name, http.MethodPut, handlerFunc, middlewareFunc...)
}
func (r *routerGroup) Patch(name string, handlerFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
   r.handle(name, http.MethodPatch, handlerFunc, middlewareFunc...)
}
func (r *routerGroup) Options(name string, handlerFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
   r.handle(name, http.MethodOptions, handlerFunc, middlewareFunc...)
}
func (r *routerGroup) Head(name string, handlerFunc HandleFunc, middlewareFunc ...MiddlewareFunc) {
   r.handle(name, http.MethodHead, handlerFunc, middlewareFunc...)
}

type Engine struct {
   router
}

func New() *Engine {
   return &Engine{
      router: router{},
   }
}
func (e *Engine) ServeHTTP(w http.ResponseWriter, r *http.Request) {
   e.httpRquestHandler(w, r)
}
func (e *Engine) Run() {
   http.Handle("/", e)
   err := http.ListenAndServe(":8111", nil)
   if err != nil {
      log.Fatal(err)
   }
}

func (e *Engine) httpRquestHandler(w http.ResponseWriter, r *http.Request) {
   method := r.Method
   for _, group := range e.routerGroups {
      routerName := SubStringLast(r.RequestURI, "/"+group.name)
      // get/1
      node := group.treeNode.Get(routerName)
      if node != nil && node.isEnd {
         //路由匹配上了
         ctx := &Context{
            W: w,
            R: r,
         }
         handle, ok := group.handleFuncMap[node.routerName][ANY]
         if ok {
            group.methodHandle(node.routerName, ANY, handle, ctx)
            handle(ctx)
            return
         }

         handle, ok = group.handleFuncMap[node.routerName][method]
         if ok {
            group.methodHandle(node.routerName, method, handle, ctx)
            return
         }
         //method 进行匹配
         w.WriteHeader(http.StatusMethodNotAllowed)
         fmt.Fprintf(w, "%s %s not allow\n", r.RequestURI, method)
         return
      }
   }
   w.WriteHeader(http.StatusNotFound)
   fmt.Fprintf(w, "%s not found\n", r.RequestURI)
}

路由级别测试代码

package main

import (
   "fmt"
   "msgo"
)

func Log(next msgo.HandleFunc) msgo.HandleFunc {
   return func(ctx *msgo.Context) {
      fmt.Println("打印请求参数")
      next(ctx)
      fmt.Println("返回执行")
   }
}

func main() {
   engine := msgo.New()
   g := engine.Group("user")
   //g.Get("/hello", func(ctx *msgo.Context) {
   // fmt.Fprintf(ctx.W, "%s Get欢迎学习GO自研框架", "lisus2000")
   //})
   g.Use(func(next msgo.HandleFunc) msgo.HandleFunc {
      return func(ctx *msgo.Context) {
         fmt.Println("pre Handle")
         next(ctx)
         fmt.Println("post Handler")
      }
   })
   g.Get("/hello/get", func(ctx *msgo.Context) {
      fmt.Fprintf(ctx.W, "%s Get欢迎学习GO自研框架", "lisus2000")
   }, Log)
   g.Post("/hello", func(ctx *msgo.Context) {
      fmt.Fprintf(ctx.W, "%s Post欢迎学习GO自研框架", "lisus2000")
   })
   g.Post("/info", func(ctx *msgo.Context) {
      fmt.Fprintf(ctx.W, "%s info功能", "lisus2000")
   })
   g.Get("/get/:id", func(ctx *msgo.Context) {
      fmt.Fprintf(ctx.W, "%s get user 路径变量的值", "lisus2000")
   })
   engine.Run()
}