装饰器

1. golang装饰器

1.1. 简单timer装饰器

package main

import (
    "fmt"
    "time"
)

func timer(fn func()) func() {
    return func() {
        startTime := time.Now().Unix()
        fn()
        endTime := time.Now().Unix()
        fmt.Println("运行时间: ", endTime-startTime)
    }
}

func testFunc() {
    fmt.Println("运行 testFunc")
    time.Sleep(time.Second * 2)
}

func main() {
    test := timer(testFunc)
    test()
}

1.2. 项目中认证实现

package main

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

type DecoratorHandler func(handlerFunc http.HandlerFunc) http.HandlerFunc

func middlewareHandlerFunc(hp http.HandlerFunc, decors ...DecoratorHandler) http.HandlerFunc {
    for _, fn := range decors {
        dp := fn
        hp = dp(hp)
    }
    return hp
}

func verifyHeader(h http.HandlerFunc) http.HandlerFunc {
    return func(w http.ResponseWriter, request *http.Request) {
        token := request.URL.Query().Get("token")
        if token == "" {
            fmt.Fprintf(w, request.URL.Path+"verifyHeader:token is null")
            return
        }
        h(w, request)
    }
}

func verifyHeader2(h http.HandlerFunc) http.HandlerFunc {
    return func(w http.ResponseWriter, request *http.Request) {
        token := request.URL.Query().Get("token")
        if token != "mimi" {
            fmt.Fprintf(w, request.URL.Path+"verifyHeader:token is mimi")
            return
        }
        h(w, request)
    }
}

func Pong(w http.ResponseWriter, request *http.Request) {
    fmt.Fprintf(w, request.URL.Path+"--> success")
}

func main() {
    http.HandleFunc("/test", middlewareHandlerFunc(Pong, verifyHeader, verifyHeader2))
    err := http.ListenAndServe(":8888", nil)
    if err != nil {
        log.Fatal("ListenAndServe:", err)
    }
}