在 Gorilla mux 处理后运行中间件

Question

我正在尝试使用 Golang 中间件在处理 Gorilla Mux 路由之后运行，以更改每个请求的响应。

代码示例见下文。目前它返回'run before，run test'，目标是使用runsafter中间件返回'run before，run test，run after'。

Gorilla Mux 可以实现类似的功能吗？

package main

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

func runsbefore(h http.Handler) http.Handler {
    fn := func(w http.ResponseWriter, r *http.Request) {
        w.Write([]byte("run before, "))
        h.ServeHTTP(w, r)
    }

    return http.HandlerFunc(fn)
}

func runsafter(h http.Handler) http.Handler {
    fn := func(w http.ResponseWriter, r *http.Request) {
        w.Write([]byte("run after, "))
        h.ServeHTTP(w, r)
    }

    return http.HandlerFunc(fn)
}

func runtest(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("run test, "))
}

func main() {
    fmt.Println("Server starting on port 8000")
    r := mux.NewRouter()
    r.HandleFunc("/", runtest).Methods("GET")
    http.ListenAndServe(":8000", runsbefore(r))
    // something like: http.ListenAndServe(":8000", runsbefore(r(runsafter)))
}

Answer 1

使用

http.ListenAndServe(":8000", runsAfter(runsbefore(r)))

并修复runsAfter中的错误：

func runsafter(h http.Handler) http.Handler {
  fn := func(w http.ResponseWriter, r *http.Request) {
    h.ServeHTTP(w, r)
    w.Write([]byte("run after, "))
  }

  return http.HandlerFunc(fn)
}