Golang基于httprouter的依赖注入中间件路由插件库nchi使用指南

nchi是一个基于httprouter构建的轻量级路由库，它提供了依赖注入和中间件支持，非常适合构建RESTful API服务。下面我将详细介绍nchi的使用方法。

安装nchi

go get github.com/muir/nchi

基本使用

package main

import (
	"fmt"
	"net/http"
	
	"github.com/muir/nchi"
)

func main() {
	router := nchi.NewRouter()
	
	router.Get("/", func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprint(w, "Hello, World!")
	})
	
	http.ListenAndServe(":8080", router)
}

中间件支持

nchi支持中间件链式调用：

func logger(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		fmt.Printf("Request: %s %s\n", r.Method, r.URL.Path)
		next.ServeHTTP(w, r)
	})
}

func auth(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		token := r.Header.Get("Authorization")
		if token != "secret" {
			http.Error(w, "Unauthorized", http.StatusUnauthorized)
			return
		}
		next.ServeHTTP(w, r)
	})
}

func main() {
	router := nchi.NewRouter()
	
	// 全局中间件
	router.Use(logger)
	
	// 路由组中间件
	api := router.Group("/api")
	api.Use(auth)
	
	api.Get("/users", func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprint(w, "User list")
	})
	
	http.ListenAndServe(":8080", router)
}

依赖注入

nchi支持依赖注入，可以将服务注入到处理器中：

type UserService struct {
	// 模拟用户服务
}

func (s *UserService) GetUsers() []string {
	return []string{"Alice", "Bob", "Charlie"}
}

func main() {
	userService := &UserService{}
	
	router := nchi.NewRouter()
	
	// 注入服务到处理器
	router.Get("/users", func(w http.ResponseWriter, r *http.Request, s *UserService) {
		users := s.GetUsers()
		fmt.Fprintf(w, "Users: %v", users)
	}).Inject(userService)
	
	http.ListenAndServe(":8080", router)
}

路由参数

nchi继承了httprouter的路由参数特性：

func main() {
	router := nchi.NewRouter()
	
	router.Get("/users/:id", func(w http.ResponseWriter, r *http.Request) {
		id := nchi.URLParam(r, "id")
		fmt.Fprintf(w, "User ID: %s", id)
	})
	
	http.ListenAndServe(":8080", router)
}

错误处理

可以自定义错误处理器：

func main() {
	router := nchi.NewRouter()
	
	// 自定义404处理器
	router.NotFound = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusNotFound)
		fmt.Fprint(w, "Custom 404 page")
	})
	
	// 自定义方法不允许处理器
	router.MethodNotAllowed = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusMethodNotAllowed)
		fmt.Fprint(w, "Method not allowed")
	})
	
	http.ListenAndServe(":8080", router)
}

完整示例

package main

import (
	"fmt"
	"log"
	"net/http"
	
	"github.com/muir/nchi"
)

type Database struct {
	// 模拟数据库
}

func (db *Database) GetUserName(id string) string {
	// 模拟数据库查询
	return "User_" + id
}

func authMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Header.Get("X-API-Key") != "secret" {
			http.Error(w, "Unauthorized", http.StatusUnauthorized)
			return
		}
		next.ServeHTTP(w, r)
	})
}

func main() {
	db := &Database{}
	router := nchi.NewRouter()
	
	// 全局中间件
	router.Use(authMiddleware)
	
	// 用户路由组
	userRouter := router.Group("/users")
	{
		userRouter.Get("/:id", func(w http.ResponseWriter, r *http.Request, db *Database) {
			id := nchi.URLParam(r, "id")
			name := db.GetUserName(id)
			fmt.Fprintf(w, "User: %s", name)
		}).Inject(db)
		
		userRouter.Post("/", func(w http.ResponseWriter, r *http.Request) {
			// 创建用户逻辑
			w.WriteHeader(http.StatusCreated)
			fmt.Fprint(w, "User created")
		})
	}
	
	// 健康检查
	router.Get("/health", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		fmt.Fprint(w, "OK")
	})
	
	log.Println("Server started on :8080")
	log.Fatal(http.ListenAndServe(":8080", router))
}

总结

nchi结合了httprouter的高性能和依赖注入的便利性，主要特点包括：

1. 基于httprouter，性能优异
2. 支持中间件链
3. 依赖注入支持
4. 简洁的API设计
5. 支持路由参数和通配符

对于需要构建高性能API且希望简化依赖管理的项目，nchi是一个很好的选择。