关于golang:浅析Go语言http服务handler对象底层原理

本文来源于: https://gobea.cn/blog/detail/15zqpwrq.html

最简略的http服务

golang

package main
import (
    "fmt"
    "net/http"
)
func main() {
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintf(w, "hello world")
    })
    http.ListenAndServe(":8899", nil)
}

http://127.0.0.1:8899hello world

http服务

golang

HandlerHandlerServeHTTPServeHTTPfunc(w http.ResponseWriter, r *http.Request)http.HandlerFuncHandlerServeMuxpatternHandlerpatternHandlerHandlerServeHTTP

handlerhandlerServeHTTPHandlerFuncServeHTTPhandler

handler对象

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

// HandlerFunc实现了Handler接口
type HandlerFunc func(ResponseWriter, *Request)
func (f HandlerFunc) ServeHTTP(w ResponseWriter, r *Request) {
    f(w, r)
}

handlerhandlerServeHTTPHandlerServeHTTP

func(w http.ResponseWriter, r *http.Requests)HandlerFuncHandlerHandlerFuncHandlerFuncServeHTTPServeHTTP

注册路由ServeMux

type ServeMux struct {
    mu    sync.RWMutex
    m     map[string]muxEntry
    hosts bool 
}

type muxEntry struct {
    explicit bool
    h        Handler
    pattern  string
}

// ServeMux也领有ServeHTTP办法,也就说ServeMux实现了Handler接口,即ServeMuX其实也是一个Handler对象,不过ServeMux的ServeHTTP办法不是用来解决request和respone，而是用来找到路由注册的handler
func (mux *ServeMux) ServeHTTP(w ResponseWriter, r *Request) {
    if r.RequestURI == "*" {
        if r.ProtoAtLeast(1, 1) {
            w.Header().Set("Connection", "close")
        }
        w.WriteHeader(StatusBadRequest)
        return
    }
    h, _ := mux.Handler(r)
    h.ServeHTTP(w, r)
}

ServeMux.mpatternHandlerServeMuxServeHTTPServeMuxHandlerServeMuXHandler

package main

import (
    "fmt"
    "net/http"
)

func main() {
    mux := http.NewServeMux()
    mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintf(w, "hello world")
    })
    mux.HandleFunc("/test", func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintf(w, "hello world")
    })
    http.ListenAndServe(":8899", mux)
}

Server

http.ListenAndServe(":8899",mux)
// 等价于
serv := &http.Server{
        Addr:    ":8899",
        Handler: mux,
    }
serv.ListenAndServe()

http.ListenAndServe源码如下:

func ListenAndServe(addr string, handler Handler) error {
    server := &Server{Addr: addr, Handler: handler}
    return server.ListenAndServe()
}

起源

• https://gobea.cn/blog/detail/…

参考

• https://www.jianshu.com/p/be3…