在使用julienschmidt/httprouter时链接中间件的最佳方法是什么?
据我谷歌搜索,http。HandlerFunc 只接受 func (w ResponseWriter, r *Request)
形式的函数,而 httprouter。句柄函数的形式为 func (w http.ResponseWriter, r *http.Request, ps httprouter.Params)
。
如何在不转换 httprouter 的情况下链接中间件。将函数处理到 http 中。汉德汉德?
例如:
我的routes.go是这样的形式,
router := httprouter.New()
router.POST("/api/user/create", middlewares.EscapeStringsMiddleware(User.CreateUser))
log.Fatal(http.ListenAndServe(":8000", router))
如何为上述路由编写中间件函数?
已经尝试过的方法:
1.
func EscapeStringsMiddleware(next http.Handler) httprouter.Handle {
return func (response http.ResponseWriter, request *http.Request, ps httprouter.Params) {
err := request.ParseForm()
if err != nil {
panic(err)
}
for key, values := range request.Form {
for i, value := range values {
value = template.HTMLEscapeString(value)
value = template.JSEscapeString(value)
request.Form[key][i] = value
}
}
next.ServeHTTP(response, request)
}
}
获得的错误:
cannot use User.CreateUser (type func(http.ResponseWriter, *http.Request, httprouter.Params)) as type http.Handler in argument to middlewares.EscapeStringsMiddleware:
func(http.ResponseWriter, *http.Request, httprouter.Params) does not implement http.Handler (missing ServeHTTP method)
阿拉伯数字。
func EscapeStringsMiddleware(next httprouter.Handle) httprouter.Handle {
return func (response http.ResponseWriter, request *http.Request, ps httprouter.Params) {
err := request.ParseForm()
if err != nil {
panic(err)
}
for key, values := range request.Form {
for i, value := range values {
value = template.HTMLEscapeString(value)
value = template.JSEscapeString(value)
request.Form[key][i] = value
}
}
next.ServeHTTP(response, request)
}
}
获得的错误:
next.ServeHTTP undefined (type httprouter.Handle has no field or method ServeHTTP)
另外,如何链接多个中间件?
例如
router.POST("/api/user/create", middlewares.VerifyCSRF(middlewares.EscapeStringsMiddleware(User.CreateUser)))
此问题与中间件处理程序无关。您正在出错User.CreateUser
因为不属于http.Handler
类型。
试试这个模式:
重要的一点是返回一个http.Handler
并用http.HandlerFunc
包装func(w http.ResponseWriter, r *http.Request)
。
func Handler() http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// do stuff
})
}
去源 :
// The HandlerFunc type is an adapter to allow the use of
// ordinary functions as HTTP handlers. If f is a function
// with the appropriate signature, HandlerFunc(f) is a
// Handler that calls f.
type HandlerFunc func(ResponseWriter, *Request)
// ServeHTTP calls f(w, r).
func (f HandlerFunc) ServeHTTP(w ResponseWriter, r *Request) {
f(w, r)
}
根据您的反馈:
httprouter.Handle
不实现ServeHTTP
。它被直接调用。例如:next(w, r, ps)
下面您将找到中间件处理程序的示例。
// Middleware without "github.com/julienschmidt/httprouter"
func StdToStdMiddleware(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// do stuff
next.ServeHTTP(w, r)
})
}
// Middleware for a standard handler returning a "github.com/julienschmidt/httprouter" Handle
func StdToJulienMiddleware(next http.Handler) httprouter.Handle {
return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
// do stuff
next.ServeHTTP(w, r)
}
}
// Pure "github.com/julienschmidt/httprouter" middleware
func JulienToJulienMiddleware(next httprouter.Handle) httprouter.Handle {
return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
// do stuff
next(w, r, ps)
}
}
func JulienHandler() httprouter.Handle {
return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
// do stuff
}
}
func StdHandler() http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// do stuff
})
}
func main() {
router := httprouter.New()
router.POST("/api/user/create", StdToJulienMiddleware(StdHandler()))
router.GET("/api/user/create", JulienToJulienMiddleware(JulienHandler()))
log.Fatal(http.ListenAndServe(":8000", router))
}
来自 https://github.com/cnvrtly/adaptr lib,其中适配器也被添加到链请求中间件函数中。
func compatibleHandler(h http.Handler, httprParamsCtxKey interface{}) httprouter.Handle {
return toHttpRouterHandle(h, httprParamsCtxKey)
}
func toHttpRouterHandle(h http.Handler, httprParamsCtxKey interface{}) func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
if httprParamsCtxKey != nil {
r = SetCtxValue(r, httprParamsCtxKey, p)
}
h.ServeHTTP(w, r)
}
}
如果您正在寻找如何定义路由的示例/想法:https://github.com/cnvrtly/golang-appengine-seed