golang httprouter

Posted 2022-08-12 lemonzwt

httprouter

httprouter 是一个高性能、可扩展的HTTP路由，上面我们列举的net/http默认路由的不足，都被httprouter 实现，我们先用一个例子，认识下 httprouter 这个强大的 HTTP 路由。

 

安装：

go get -u github.com/julienschmidt/httprouter

在这个例子中，首先通过httprouter.New()生成了一个*Router路由指针,然后使用GET方法注册一个适配/路径的Index函数，最后*Router作为参数传给ListenAndServe函数启动HTTP服务即可。

package main

import (
	"log"
	"net/http"

	"github.com/julienschmidt/httprouter"
)

func Index(w http.ResponseWriter, r *http.Request, _ httprouter.Params) 
	w.Write([]byte("Index"))


func main() 
	router := httprouter.New()
	router.GET("/", Index)
	log.Fatal(http.ListenAndServe(":8080", router))

httprouter 为所有的HTTP Method 提供了快捷的使用方式，只需要调用对应的方法即可。

func (r *Router) GET(path string, handle Handle) 
	r.Handle("GET", path, handle)


func (r *Router) HEAD(path string, handle Handle) 
	r.Handle("HEAD", path, handle)


func (r *Router) OPTIONS(path string, handle Handle) 
	r.Handle("OPTIONS", path, handle)


func (r *Router) POST(path string, handle Handle) 
	r.Handle("POST", path, handle)


func (r *Router) PUT(path string, handle Handle) 
	r.Handle("PUT", path, handle)


func (r *Router) PATCH(path string, handle Handle) 
	r.Handle("PATCH", path, handle)


func (r *Router) DELETE(path string, handle Handle) 
	r.Handle("DELETE", path, handle)

现代的API，基本上都是Restful API，httprouter提供的命名参数的支持，可以很方便的帮助我们开发Restful API。比如我们设计的API/user/flysnow，这这样一个URL，可以查看flysnow这个用户的信息，如果要查看其他用户的，比如zhangsan,我们只需要访问API/user/zhangsan即可。

URL包括两种匹配模式：/user/:name精确匹配、/user/*name匹配所有的模式。

package main

import (
  "github.com/julienschmidt/httprouter"
  "net/http"
  "log"
  "fmt"
)


func main()  
  router:=httprouter.New()
  router.GET("/MainData", func (w http.ResponseWriter,r *http.Request,_ httprouter.Params)  
    w.Write([]byte("default get"))
  )
  router.POST("/MainData",func (w http.ResponseWriter,r *http.Request,_ httprouter.Params)  
    w.Write([]byte("default post"))
  )
  //精确匹配
  router.GET("/user/name",func (w http.ResponseWriter,r *http.Request,p httprouter.Params)  
    w.Write([]byte("user name:"+p.ByName("name")))
  )
  //匹配所有
  router.GET("/employee/*name",func (w http.ResponseWriter,r *http.Request,p httprouter.Params)  
    w.Write([]byte("employee name:"+p.ByName("name")))
  )
  http.ListenAndServe(":8081", router)

Handler处理链处理不同二级域名

package main

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

	"github.com/julienschmidt/httprouter"
)

type HostMap map[string]http.Handler

func (hs HostMap) ServeHTTP(w http.ResponseWriter, r *http.Request) 
	fmt.Println("222")
	//根据域名获取对应的Handler路由，然后调用处理（分发机制）
	if handler := hs[r.Host]; handler != nil 
		handler.ServeHTTP(w, r)
	 else 
		http.Error(w, "Forbidden", 403)
	


func main() 
	userRouter := httprouter.New()
	userRouter.GET("/", func(w http.ResponseWriter, r *http.Request, p httprouter.Params) 
		w.Write([]byte("play"))
	)

	dataRouter := httprouter.New()
	dataRouter.GET("/", func(w http.ResponseWriter, r *http.Request, _ httprouter.Params) 
		w.Write([]byte("tool"))
	)

	//分别用于处理不同的二级域名
	hs := make(HostMap)
	hs["user.localhost:12345"] = userRouter
	hs["data.localhost:12345"] = dataRouter

	log.Fatal(http.ListenAndServe(":12345", hs))

httprouter提供了很方便的静态文件服务，可以把一个目录托管在服务器上，以供访问。

router.ServeFiles("/static/*filepath",http.Dir("./"))

使用ServeFiles需要注意的是，第一个参数路径，必须要以/*filepath，因为要获取我们要访问的路径信息。

func (r *Router) ServeFiles(path string, root http.FileSystem) 
	if len(path) < 10 || path[len(path)-10:] != "/*filepath" 
		panic("path must end with /*filepath in path ‘" + path + "‘")
	

	fileServer := http.FileServer(root)

	r.GET(path, func(w http.ResponseWriter, req *http.Request, ps Params) 
		req.URL.Path = ps.ByName("filepath")
		fileServer.ServeHTTP(w, req)
	)

例子：

package main

import (
	"log"
	"net/http"

	"github.com/julienschmidt/httprouter"
)

func main() 
	router := httprouter.New()
  //访问静态文件
	router.ServeFiles("/static/*filepath", http.Dir("./files"))
	log.Fatal(http.ListenAndServe(":8080", router))

httprouter 异常捕获，httprouter允许使用者，设置PanicHandler用于处理HTTP请求中发生的panic。

package main

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

	"github.com/julienschmidt/httprouter"
)

func Index(w http.ResponseWriter, r *http.Request, _ httprouter.Params) 
	panic("error")


func main() 
	router := httprouter.New()
	router.GET("/", Index)
  //捕获异常
	router.PanicHandler = func(w http.ResponseWriter, r *http.Request, v interface) 
		w.WriteHeader(http.StatusInternalServerError)
		fmt.Fprintf(w, "error:%s", v)
	
	log.Fatal(http.ListenAndServe(":8080", router))

httprouter还有不少有用的小功能，比如对404进行处理，我们通过设置Router.NotFound来实现，我们看看Router这个结构体的配置，可以发现更多有用的功能。

type Router struct 
    //是否通过重定向，给路径自定加斜杠
	RedirectTrailingSlash bool
    //是否通过重定向，自动修复路径，比如双斜杠等自动修复为单斜杠
	RedirectFixedPath bool
    //是否检测当前请求的方法被允许
	HandleMethodNotAllowed bool
	//是否自定答复OPTION请求
	HandleOPTIONS bool
    //404默认处理
	NotFound http.Handler
    //不被允许的方法默认处理
	MethodNotAllowed http.Handler
    //异常统一处理
	PanicHandler func(http.ResponseWriter, *http.Request, interface)