Golang高性能HTTP路由处理库httprouter使用指南

httprouter是一个轻量级、高性能的HTTP请求路由器（也称为多路复用器），专为Go语言设计。它比标准库的net/http路由器更快，支持参数化路由，并且内存占用极低。

安装

go get github.com/julienschmidt/httprouter

基本使用

package main

import (
	"fmt"
	"log"
	"net/http"
	"github.com/julienschmidt/httprouter"
)

func Index(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
	fmt.Fprint(w, "Welcome!\n")
}

func Hello(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
	fmt.Fprintf(w, "hello, %s!\n", ps.ByName("name"))
}

func main() {
	router := httprouter.New()
	router.GET("/", Index)
	router.GET("/hello/:name", Hello)

	log.Fatal(http.ListenAndServe(":8080", router))
}

核心特性

1. 参数化路由

httprouter支持在路径中定义参数：

router.GET("/user/:name", func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
    name := ps.ByName("name")
    fmt.Fprintf(w, "Hello %s", name)
})

2. 通配符路由

使用*可以匹配任意路径：

router.GET("/static/*filepath", func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
    filepath := ps.ByName("filepath")
    fmt.Fprintf(w, "Requested file: %s", filepath)
})

3. 路由优先级

httprouter有明确的路由优先级规则：

1. 静态路径优先于参数化路径
2. 参数化路径优先于通配符路径

4. 自动处理OPTIONS请求和405错误

httprouter会自动处理OPTIONS请求，并返回405 Method Not Allowed错误。

高级用法

1. 自定义Panic处理

router.PanicHandler = func(w http.ResponseWriter, r *http.Request, err interface{}) {
    log.Printf("Panic: %v", err)
    http.Error(w, "Internal Server Error", http.StatusInternalServerError)
}

2. 自定义NotFound处理

router.NotFound = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    w.WriteHeader(http.StatusNotFound)
    fmt.Fprintf(w, "404 Not Found")
})

3. 自定义MethodNotAllowed处理

router.MethodNotAllowed = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    w.WriteHeader(http.StatusMethodNotAllowed)
    fmt.Fprintf(w, "405 Method Not Allowed")
})

4. 中间件支持

虽然httprouter本身不直接支持中间件，但可以很容易地包装处理函数：

func Logger(fn httprouter.Handle) httprouter.Handle {
    return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
        start := time.Now()
        fn(w, r, ps)
        log.Printf("%s %s %v", r.Method, r.URL.Path, time.Since(start))
    }
}

// 使用中间件
router.GET("/protected", Logger(ProtectedHandler))

性能优化技巧

1. 避免在热路径中分配内存：在路由处理函数中避免不必要的内存分配
2. 重用参数：如果可能，重用httprouter.Params对象
3. 减少路由数量：合并相似的路由，使用参数化路由
4. 使用sync.Pool：对于频繁创建的对象，考虑使用sync.Pool

与标准库对比

httprouter相比标准库net/http的ServeMux有以下优势：

• 更快的路由查找
• 支持路径参数
• 明确的路由优先级
• 更少的内存占用
• 自动处理OPTIONS和405

完整示例

package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"github.com/julienschmidt/httprouter"
)

type User struct {
	ID   string `json:"id"`
	Name string `json:"name"`
}

var users = map[string]User{
	"1": {ID: "1", Name: "Alice"},
	"2": {ID: "2", Name: "Bob"},
}

func GetUser(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
	id := ps.ByName("id")
	user, exists := users[id]
	if !exists {
		w.WriteHeader(http.StatusNotFound)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(user)
}

func CreateUser(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
	var user User
	err := json.NewDecoder(r.Body).Decode(&user)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	users[user.ID] = user
	w.WriteHeader(http.StatusCreated)
}

func main() {
	router := httprouter.New()
	
	// 设置自定义处理器
	router.NotFound = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(404)
		fmt.Fprint(w, "Custom 404 Page")
	})
	
	// 路由定义
	router.GET("/users/:id", GetUser)
	router.POST("/users", CreateUser)
	
	// 静态文件服务
	router.ServeFiles("/static/*filepath", http.Dir("./public"))
	
	log.Println("Server started on :8080")
	log.Fatal(http.ListenAndServe(":8080", router))
}

httprouter是构建高性能HTTP服务的优秀选择，特别适合需要高效路由和参数化路径的应用程序。