go 微服务框架kratos使用中间件的方法

type Handler interface {
	ServeHTTP(ResponseWriter, *Request)
}

package main
import (
	"fmt"
	"log"
	"net/http"
)
// 日志记录中间件
func loggingMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		log.Printf("请求处理之前   Request URI: %s\n", r.RequestURI)
		next.ServeHTTP(w, r)
		log.Printf("处理程序之后进行的操作...\n")
	})
}
// handler 处理函数
func SayHello(w http.ResponseWriter, r *http.Request) {
	fmt.Println("Hello world")
}
func main() {
	//创建一个 HTTP 请求路由器
	mux := http.NewServeMux()
	// 使用日志记录中间件
	mux.Handle("/index", loggingMiddleware(http.HandlerFunc(SayHello)))
	//启动服务，使用创建的 ServeMux
	http.ListenAndServe(":8081", mux)
}

func NewHTTPServer(c *conf.Server, logger log.Logger, blog *service.BlogService) *http.Server {
	opts := []http.ServerOption{
		http.Middleware(
			//使用kratos内置中间件
			recovery.Recovery(),
			tracing.Server(),
			logging.Server(logger),
			validate.Validator(),
		),
	}
	if c.Http.Network != "" {
		opts = append(opts, http.Network(c.Http.Network))
	}
	if c.Http.Addr != "" {
		opts = append(opts, http.Address(c.Http.Addr))
	}
	if c.Http.Timeout != nil {
		opts = append(opts, http.Timeout(c.Http.Timeout.AsDuration()))
	}
	//创建 httpServer 
	srv := http.NewServer(opts...)
	v1.RegisterBlogServiceHTTPServer(srv, blog)
	return srv
}

// Handler defines the handler invoked by Middleware.
type Handler func(ctx context.Context, req interface{}) (interface{}, error)
// Middleware is HTTP/gRPC transport middleware.
type Middleware func(Handler) Handler

// auth.go 单元
//自定义 JWT 认证中间件
func JWTAuth(jwtSecret string) middleware.Middleware {
	return func(handler middleware.Handler) middleware.Handler {
		return func(ctx context.Context, req interface{}) (reply interface{}, err error) {
			if tr, ok := transport.FromServerContext(ctx); ok {
				tokenString := tr.RequestHeader().Get("authorization")
				spew.Dump(tokenString)
				//token, err := jwt.ParseWithClaims(tokenString, &jwt.StandardClaims{}, func(token *jwt.Token) (interface{}, error) {
				token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
					// Don't forget to validate the alg is what you expect:
					if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
						return nil, fmt.Errorf("Unexpected signing method: %v", token.Header["alg"])
					}
					// hmacSampleSecret is a []byte containing your secret, e.g. []byte("my_secret_key")
					return []byte(jwtSecret), nil
				})
				if err != nil {
					log.Fatal(err)
				}
				if claims, ok := token.Claims.(jwt.MapClaims); ok {
					fmt.Println(claims["iss"], claims["exp"])
					//fmt.Println(claims.Issuer, claims.ExpiresAt)
				} else {
					fmt.Println(err)
				}
			}
			return handler(ctx, req)
		}
	}
}
// server/http.go 单元
func NewHTTPServer(c *conf.Server, confAuth *conf.Auth, logger log.Logger, blog *service.BlogService) *http.Server {
	opts := []http.ServerOption{
		http.Middleware(
			//自定义中间件 JWTAuth
			auth.JWTAuth(confAuth.JwtSecrect),
		),
	}
	if c.Http.Network != "" {
		opts = append(opts, http.Network(c.Http.Network))
	}
	if c.Http.Addr != "" {
		opts = append(opts, http.Address(c.Http.Addr))
	}
	if c.Http.Timeout != nil {
		opts = append(opts, http.Timeout(c.Http.Timeout.AsDuration()))
	}
	//创建 httpServer 
	srv := http.NewServer(opts...)
	v1.RegisterBlogServiceHTTPServer(srv, blog)
	return srv
}

// server/http.go 单元
// 添加验证白名单
func NewWhiteListMatcher() selector.MatchFunc {
	whiteList := make(map[string]struct{})
	whiteList["/blog.api.v1.Account/Login"] = struct{}{}
	whiteList["/blog.api.v1.Account/Register"] = struct{}{}
	return func(ctx context.Context, operation string) bool {
		if _, ok := whiteList[operation]; ok {
			return false
		}
		return true
	}
}
// server/http.go 单元
func NewHTTPServer(c *conf.Server, confAuth *conf.Auth, logger log.Logger, blog *service.BlogService) *http.Server {
	opts := []http.ServerOption{
		http.Middleware(
			//自定义中间件 JWTAuth
			selector.Server(auth.JWTAuth(confAuth.JwtSecrect)).
				Match(NewWhiteListMatcher()).
				Build(),
		),
	}
	if c.Http.Network != "" {
		opts = append(opts, http.Network(c.Http.Network))
	}
	if c.Http.Addr != "" {
		opts = append(opts, http.Address(c.Http.Addr))
	}
	if c.Http.Timeout != nil {
		opts = append(opts, http.Timeout(c.Http.Timeout.AsDuration()))
	}
	//创建 httpServer 
	srv := http.NewServer(opts...)
	v1.RegisterBlogServiceHTTPServer(srv, blog)
	return srv
}