golang httprouter

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{})
}

原文链接：https://www.cnblogs.com/lemonzwt/p/11391755.html

golang httprouter

httprouter

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