Question

我来自node express，我能够传入尽可能多的中间件，例如：routes.use('/*', ensureAuth, logImportant, ... n);

使用r.GET("/", HomeIndex)时如何做类似的事情？

我是否被迫做EnsureAuth(HomeIndex)之类的事情？因为我可以让它工作。不幸的是，我不确定在不将函数链接在一起的情况下添加尽可能多的中间件会是什么好方法。

是否有更优雅的方式，所以我可以某种方式使用可变参数类型函数来r.GET("/", applyMiddleware(HomeIndex, m1, m2, m3, m4)？我现在正在尝试，但我觉得有更好的方法来做到这一点。

我看过httprouter问题页面，找不到任何东西:(

谢谢！

Answer 1

以下是我如何做到的示例：

package main

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

    "github.com/julienschmidt/httprouter"
    "github.com/justinas/alice"
)

// m1 is middleware 1
func m1(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        //do something with m1
        log.Println("m1 start here")
        next.ServeHTTP(w, r)
        log.Println("m1 end here")
    })
}

// m2 is middleware 2
func m2(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        //do something with m2
        log.Println("m2 start here")
        next.ServeHTTP(w, r)
        log.Println("m2 end here")
    })
}

func index(w http.ResponseWriter, r *http.Request) {
    // get httprouter.Params from request context
    ps := r.Context().Value("params").(httprouter.Params)
    fmt.Fprintf(w, "Hello, %s", ps.ByName("name"))
}

// wrapper wraps http.Handler and returns httprouter.Handle
func wrapper(next http.Handler) httprouter.Handle {
    return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
        //pass httprouter.Params to request context
        ctx := context.WithValue(r.Context(), "params", ps)
        //call next middleware with new context
        next.ServeHTTP(w, r.WithContext(ctx))
    }
}

func main() {
    router := httprouter.New()

    chain := alice.New(m1, m2)

    //need to wrap http.Handler to be compatible with httprouter.Handle
    router.GET("/user/:name", wrapper(chain.ThenFunc(index)))

    log.Fatal(http.ListenAndServe(":9000", router))
}

代码链接（不能从play.golang.org运行）：https://play.golang.org/p/BOCt97xcoY

httprouter传递了许多中间件函数

1 个答案: