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

huangapple
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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：

  1. router := httprouter.New()
  2. router.POST("/api/user/create", middlewares.EscapeStringsMiddleware(User.CreateUser))
  3. 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：

  1. func EscapeStringsMiddleware(next http.Handler) httprouter.Handle {
  2.     return func(response http.ResponseWriter, request *http.Request, ps httprouter.Params) {
  3.         err := request.ParseForm()
  4.         if err != nil {
  5.             panic(err)
  6.         }
  8.         for key, values := range request.Form {
  9.             for i, value := range values {
  10.                 value = template.HTMLEscapeString(value)
  11.                 value = template.JSEscapeString(value)
  12.                 request.Form[key][i] = value
  13.             }
  14.         }
  15.         next.ServeHTTP(response, request)
  16.     }
  17. }

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）

  1. func EscapeStringsMiddleware(next httprouter.Handle) httprouter.Handle {
  2.     return func(response http.ResponseWriter, request *http.Request, ps httprouter.Params) {
  3.         err := request.ParseForm()
  4.         if err != nil {
  5.             panic(err)
  6.         }
  8.         for key, values := range request.Form {
  9.             for i, value := range values {
  10.                 value = template.HTMLEscapeString(value)
  11.                 value = template.JSEscapeString(value)
  12.                 request.Form[key][i] = value
  13.             }
  14.         }
  15.         next.ServeHTTP(response, request)
  16.     }
  17. }

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：

  1. 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,

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

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

Already tried methods:

1.

  1. func EscapeStringsMiddleware(next http.Handler) httprouter.Handle {
  2. 	
  3. 	return func (response http.ResponseWriter, request *http.Request, ps httprouter.Params) {
  4. 		err := request.ParseForm()
  5. 		if err != nil {
  6. 			panic(err)
  7. 		}
  9. 		for key, values := range request.Form {
  10. 			for i, value := range values {
  11. 				value = template.HTMLEscapeString(value)
  12. 				value = template.JSEscapeString(value)
  13. 				request.Form[key][i] = value
  14. 			}
  15. 		}
  16. 		next.ServeHTTP(response, request)
  17. 	}
  18. }

Error obtained:

  1. cannot use User.CreateUser (type func(http.ResponseWriter, *http.Request, httprouter.Params)) as type http.Handler in argument to middlewares.EscapeStringsMiddleware:
  2. func(http.ResponseWriter, *http.Request, httprouter.Params) does not implement http.Handler (missing ServeHTTP method)

2.

  1. func EscapeStringsMiddleware(next httprouter.Handle) httprouter.Handle {
  2. 	
  3. 	return func (response http.ResponseWriter, request *http.Request, ps httprouter.Params) {
  4. 		err := request.ParseForm()
  5. 		if err != nil {
  6. 			panic(err)
  7. 		}
  9. 		for key, values := range request.Form {
  10. 			for i, value := range values {
  11. 				value = template.HTMLEscapeString(value)
  12. 				value = template.JSEscapeString(value)
  13. 				request.Form[key][i] = value
  14. 			}
  15. 		}
  16. 		next.ServeHTTP(response, request)
  17. 	}
  18. }

Error obtained:

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

Also how do I chain multiple middleware?

For example,

  1. 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)。

  1. func Handler() http.Handler {
  2.     return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  3.         // do stuff
  4.     })
  5. }

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：

  1. // 无需 "github.com/julienschmidt/httprouter" 的中间件
  2. func StdToStdMiddleware(next http.Handler) http.Handler {
  4.     return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  5.         // do stuff
  6.         next.ServeHTTP(w, r)
  7.     })
  8. }
  10. // 用于返回 "github.com/julienschmidt/httprouter" Handle 的标准处理程序的中间件
  11. func StdToJulienMiddleware(next http.Handler) httprouter.Handle {
  13.     return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
  14.         // do stuff
  15.         next.ServeHTTP(w, r)
  16.     }
  17. }
  19. // 纯粹的 "github.com/julienschmidt/httprouter" 中间件
  20. func JulienToJulienMiddleware(next httprouter.Handle) httprouter.Handle {
  22.     return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
  23.         // do stuff
  24.         next(w, r, ps)
  25.     }
  26. }
  28. func JulienHandler() httprouter.Handle {
  29.     return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
  30.         // do stuff
  31.     }
  32. }
  34. func StdHandler() http.Handler {
  35.     return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  36.         // do stuff
  37.     })
  38. }
  40. func main() {
  41.     router := httprouter.New()
  42.     router.POST("/api/user/create", StdToJulienMiddleware(StdHandler()))
  43.     router.GET("/api/user/create", JulienToJulienMiddleware(JulienHandler()))
  44.     log.Fatal(http.ListenAndServe(":8000", router))
  45. }

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.

  1. func Handler() http.Handler {
  2. return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  3. // do stuff
  4. })
  5. }

go source :

  1. // The HandlerFunc type is an adapter to allow the use of
  2. // ordinary functions as HTTP handlers. If f is a function
  3. // with the appropriate signature, HandlerFunc(f) is a
  4. // Handler that calls f.
  5. type HandlerFunc func(ResponseWriter, *Request)
  6. // ServeHTTP calls f(w, r).
  7. func (f HandlerFunc) ServeHTTP(w ResponseWriter, r *Request) {
  8. f(w, r)
  9. }

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.

  1. // Middleware without "github.com/julienschmidt/httprouter"
  2. func StdToStdMiddleware(next http.Handler) http.Handler {
  3. return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  4. // do stuff
  5. next.ServeHTTP(w, r)
  6. })
  7. }
  8. // Middleware for a standard handler returning a "github.com/julienschmidt/httprouter" Handle
  9. func StdToJulienMiddleware(next http.Handler) httprouter.Handle {
  10. return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
  11. // do stuff
  12. next.ServeHTTP(w, r)
  13. }
  14. }
  15. // Pure "github.com/julienschmidt/httprouter" middleware
  16. func JulienToJulienMiddleware(next httprouter.Handle) httprouter.Handle {
  17. return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
  18. // do stuff
  19. next(w, r, ps)
  20. }
  21. }
  22. func JulienHandler() httprouter.Handle {
  23. return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
  24. // do stuff
  25. }
  26. }
  27. func StdHandler() http.Handler {
  28. return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  29. // do stuff
  30. })
  31. }
  32. func main() {
  33. router := httprouter.New()
  34. router.POST("/api/user/create", StdToJulienMiddleware(StdHandler()))
  35. router.GET("/api/user/create", JulienToJulienMiddleware(JulienHandler()))
  36. log.Fatal(http.ListenAndServe(":8000", router))
  37. }

答案2

得分: 0

从 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。

  1. func compatibleHandler(h http.Handler, httprParamsCtxKey interface{}) httprouter.Handle {
  2. 	return toHttpRouterHandle(h, httprParamsCtxKey)
  3. }
  5. func toHttpRouterHandle(h http.Handler, httprParamsCtxKey interface{}) func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
  6. 	return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
  7. 		if httprParamsCtxKey != nil {
  8. 			r = SetCtxValue(r, httprParamsCtxKey, p)
  9. 		}
  10. 		h.ServeHTTP(w, r)
  11. 	}
  12. }

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.

  1. func compatibleHandler(h http.Handler, httprParamsCtxKey interface{}) httprouter.Handle {
  2. return toHttpRouterHandle(h, httprParamsCtxKey)
  3. }
  4. func toHttpRouterHandle(h http.Handler, httprParamsCtxKey interface{}) func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
  5. return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
  6. if httprParamsCtxKey != nil {
  7. r = SetCtxValue(r, httprParamsCtxKey, p)
  8. }
  9. h.ServeHTTP(w, r)
  10. }
  11. }

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
  • go
  • middleware
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