Gorilla mux自定义中间件

Question

我正在使用gorilla mux来管理路由。我缺少的是在每个请求之间集成一个中间件。

例如

package main

import (
    "fmt"
    "github.com/gorilla/mux"
    "log"
    "net/http"
    "strconv"
)

func HomeHandler(response http.ResponseWriter, request *http.Request) {

    fmt.Fprintf(response, "Hello home")
}

func main() {

    port := 3000
    portstring := strconv.Itoa(port)

    r := mux.NewRouter()
    r.HandleFunc("/", HomeHandler)
    http.Handle("/", r)

    log.Print("Listening on port " + portstring + " ... ")
    err := http.ListenAndServe(":"+portstring, nil)
    if err != nil {
        log.Fatal("ListenAndServe error: ", err)
    }
}

每个传入的请求都应该通过中间件。我如何在这里集成中间件？

更新

我将把它与gorilla/session结合使用，他们会说：

重要提示:如果你没有使用gorilla/mux，你需要用context.ClearHandler包装你的处理程序，否则你会泄漏内存！一种简单的方法是在调用http.ListenAndServe时包装顶级多路复用器：

我如何防止这种情况发生？

Answer 1

只需创建一个包装器，这在Go中相当简单：

func HomeHandler(response http.ResponseWriter, request *http.Request) {

    fmt.Fprintf(response, "Hello home")
}

func Middleware(h http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        log.Println("middleware", r.URL)
        h.ServeHTTP(w, r)
    })
}
func main() {
    r := mux.NewRouter()
    r.HandleFunc("/", HomeHandler)
    http.Handle("/", Middleware(r))
}

Answer 2

func Middleware(h http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        // do stuff
        h.ServeHTTP(w, r)
    })
}
func Middleware2(s string) mux.MiddlewareFunc {
    return func(h http.Handler) http.Handler {
        return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
            // do stuff
            fmt.Println(s)
            h.ServeHTTP(w, r)
        })
    }
}
func main() {
    router := mux.NewRouter()


    router.Use(Middleware)
    //you can apply it to a sub-router too
    subRouter := router.PathPrefix("/sub_router/").Subrouter()
    subRouter.Use(Middleware2("somePrams"))
    // Add more middleware if you need call router.Use Again
    // router.Use(Middleware3, Middleware4, Middleware5)

    _ = http.ListenAndServe(":80", router)
}

the official doc on the mux website

Answer 3

我不确定为什么@OneOfOne选择将路由器链接到中间件中，我认为这是一个稍微好一点的方法：

func main() {
    r.Handle("/",Middleware(http.HandlerFunc(homeHandler)))
    http.Handle("/", r)
}

func Middleware(h http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    h.ServeHTTP(w, r)
})}