golang利用不到20行代码实现路由调度详解

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

type application struct {
 routes map[string]interface{}
}

func New() *application {
 return &application{
  routes: make(map[string]interface{}),
 }
}

func (p *application) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 controllerName := r.URL.Query().Get("c")
 actionName := r.URL.Query().Get("a")
 if controllerName == "" || actionName == "" {
  http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
  return
 }
 route, ok := p.routes[controllerName]
 if !ok {
  http.Error(w, "Controller Not Found", http.StatusNotFound)
  return
 }
 ele := reflect.ValueOf(route).Elem()
 ele.FieldByName("Request").Set(reflect.ValueOf(r))
 ele.FieldByName("Response").Set(reflect.ValueOf(w))
 ele.MethodByName(actionName).Call([]reflect.Value{})
}

func (p *application) printRoutes() {
 for route, controller := range p.routes {
  ele := reflect.ValueOf(controller).Type().String()
  fmt.Printf("%s %s\n", route, ele)
 }
}

func (p *application) Get(route string, controller interface{}) {
 p.routes[route] = controller
}

func (p *application) Run(addr string) error {
 p.printRoutes()
 fmt.Printf("listen on %s\n", addr)
 return http.ListenAndServe(addr, p)
}

package app

import "net/http"

type Controller struct {
 Response http.ResponseWriter
 Request *http.Request
}

package controllers

import (
 "fmt"
 "app"
)

type SiteController struct {
 app.Controller
}

func (p SiteController) Index() {
 fmt.Fprint(p.Response, p.Request.RequestURI)
}

package main

import (
 _ "github.com/go-sql-driver/mysql"
 "app"
 "controllers"
)

func main() {
 application := app.New()
 application.Get("site", &controllers.SiteController{})
 application.Run(":8080")
}