How to use middlewares when using julienschmidt/httprouter in goLang?

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英文:

How to use middlewares when using julienschmidt/httprouter in goLang?

问题

使用julienschmidt/httprouter时,如何以最佳方式链接中间件?

根据我搜索的结果,http.HandlerFunc只接受形式为func (w ResponseWriter, r *Request)的函数,而httprouter.Handle函数的形式为func (w http.ResponseWriter, r *http.Request, ps httprouter.Params)

如何在不将httprouter.Handle函数转换为http.HandlerFunc的情况下链接中间件?

例如:
我的routes.go文件的形式如下:

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?

已尝试的方法:

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:

无法将User.CreateUser(类型为func(http.ResponseWriter, *http.Request, httprouter.Params))作为middlewares.EscapeStringsMiddleware的参数类型http.Handler:
func(http.ResponseWriter, *http.Request, httprouter.Params)未实现http.Handler(缺少ServeHTTP方法)

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未定义(类型httprouter.Handle没有ServeHTTP字段或方法)

另外,如何链接多个中间件?

例如:

router.POST("/api/user/create", middlewares.VerifyCSRF(middlewares.EscapeStringsMiddleware(User.CreateUser)))
英文:

What's the best way to chain middlewares while using julienschmidt/httprouter?

As far as I have googled, http.HandlerFunc accepts functions only in the form func (w ResponseWriter, r *Request) whereas httprouter.Handle functions are of the form func (w http.ResponseWriter, r *http.Request, ps httprouter.Params).

How to I chain middlewares without converting the httprouter.Handle function into http.HandlerFunc?

For example:
My routes.go is of the form,

router	:=	httprouter.New()
router.POST("/api/user/create", middlewares.EscapeStringsMiddleware(User.CreateUser))
log.Fatal(http.ListenAndServe(":8000",	router))

How do I write middleware functions for the above mentioned route?

Already tried methods:

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)
	}
}

Error obtained:

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)

2.

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)
	}
}

Error obtained:

next.ServeHTTP undefined (type httprouter.Handle has no field or method ServeHTTP)

Also how do I chain multiple middleware?

For example,

router.POST("/api/user/create", middlewares.VerifyCSRF(middlewares.EscapeStringsMiddleware(User.CreateUser)))

答案1

得分: 17

这个问题与你的中间件处理程序无关。你之所以出错是因为User.CreateUser不是http.Handler类型。

尝试使用以下模式:

重要的部分是返回一个http.Handler,并使用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
    })
}

根据你的反馈:

httprouter.Handle没有实现ServeHTTP。它直接被调用。例如:next(w, r, ps)

以下是中间件处理程序的示例:

// 无需 "github.com/julienschmidt/httprouter" 的中间件
func StdToStdMiddleware(next http.Handler) http.Handler {

    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        // do stuff
        next.ServeHTTP(w, r)
    })
}

// 用于返回 "github.com/julienschmidt/httprouter" Handle 的标准处理程序的中间件
func StdToJulienMiddleware(next http.Handler) httprouter.Handle {

    return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
        // do stuff
        next.ServeHTTP(w, r)
    }
}

// 纯粹的 "github.com/julienschmidt/httprouter" 中间件
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))
}

希望对你有帮助!

英文:

This issue is not with your middleware handler. You are getting errs because User.CreateUser is not of type http.Handler.

Try this pattern :

The important bit is to return a http.Handler and wrap func(w http.ResponseWriter, r *http.Request) with http.HandlerFunc.

func Handler() http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// do stuff
})
}

go source :

// 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)
}

Based on your feedback:

httprouter.Handle does not implement ServeHTTP. It is called directly. For example : next(w, r, ps)

Below you will find examples of middleware handlers.

// 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))
}

答案2

得分: 0

https://github.com/cnvrtly/adaptr 库中,适配器也被添加到链式请求中间件函数中。

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)
	}
}

如果你正在寻找如何定义路由的示例/想法,请参考 https://github.com/cnvrtly/golang-appengine-seed

英文:

From https://github.com/cnvrtly/adaptr lib where adapters are also added to chain request middleware functions.

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)
}
}

If you are looking for example/idea how to define routes: https://github.com/cnvrtly/golang-appengine-seed

huangapple
  • 本文由 发表于 2017年5月14日 21:31:25
  • 转载请务必保留本文链接:https://go.coder-hub.com/43964461.html
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