为什么这里只调用了 H1
的 ServeHTTP
方法,而 H2
和 H3
似乎是被忽略了?
alice似乎是一个不错的中间件链接,在这里我尝试将它与 httprouter 一起使用,但只有外部/最后一个中间件被调用:
package main
import (
"fmt"
"github.com/julienschmidt/httprouter"
"github.com/justinas/alice"
"net/http"
"log"
"time"
)
func main() {
fmt.Println("started ", time.Now())
c := alice.New(S1, S2, S3).Then(nil)
router := httprouter.New()
router.Handler("GET", "/app", c)
http.ListenAndServe(":27007", router)
}
func S1(h http.Handler) http.Handler {
var x H1
return &x
}
func S2(h http.Handler) http.Handler {
var x H2
return &x
}
func S3(h http.Handler) http.Handler {
var x H3
return &x
}
type H1 struct{}
func (h *H1) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
log.Println("H1", time.Now())
}
type H2 struct{}
func (h *H2) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
log.Println("H2")
}
type H3 struct{}
func (h *H3) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
log.Println("H3")
}
最佳答案
您的中间件处理程序需要在准备就绪时调用下一个处理程序。未经测试的例子:
func S1(h http.Handler) http.Handler {
return &H1{next: h}
}
type H1 struct{
next http.Handler
}
func (h *H1) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
log.Println("H1", time.Now())
h.next.ServeHTTP(rw, req)
}
或者:
func S1(next http.Handler) http.Handler {
return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
log.Println("H1", time.Now())
next(rw, req)
})
}
看http://golang.org/src/net/http/server.go?s=37638:37688#L1280中间件的另一个例子。
关于web-applications - `alice` 未调用中间件,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/28676536/