Go编程基础4-Http服务器

1、http服务器

package main
import(
    "net/http"
    "log"
)
func main(){//注册某个函数专门响应某个路由"/"，函数签名符合
    http.HandleFunc("/",func(w http.ResponseWriter,r *http.Request){ 
        w.Write([]byte("Hello,this is version 1!"))
    })
    http.HandleFunc("/bye",sayBye)
    log.Println("Starting server ... v1")
    log.Fatal(http.ListenAndServe(":4000",nil))
}
func sayBye( w http.ResponseWriter,r *http.Request){
    w.Write([]byte("Bye bye,this is version 1!"))
}
go run test.go
2018/07/09 14:32:08 Starting server ... v1

浏览器打开访问：http://localhost:4000/

浏览器打开访问：http://localhost:4000/bye

如何使用mux自定义ServeHTTP，实现http server呢？

package main
import(
    "net/http"
    "log"
)
func main(){
    mux := http.NewServeMux()
    mux.Handle("/",&myHandler{})
    mux.HandleFunc("bye",sayBye)

    log.Println("Starting server ... v2")
    log.Fatal(http.ListenAndServe(":4000",mux))
}
type myHandler struct {}
func (*myHandler) ServeHTTP(w http.ResponseWriter,r *http.Request){
    w.Write([]byte("Hello,this is version 2!"))
}
func sayBye(w http.ResponseWriter,r *http.Request){
    w.Write([]byte("Bye bye,this is version 2!"))
}
go run test.go
2018/07/09 15:37:35 Starting server ... v2

浏览器打开访问：http://localhost:4000/

浏览器打开访问：http://localhost:4000/bye

浏览器打开访问：http://localhost:4000/abcdef 默认也匹配到这里

所有未匹配到的路由都会匹配到跟 "/" 路由

package main
import(
    "net/http"
    "log"
)
func main(){
    mux := http.NewServeMux()
    mux.Handle("/",&myHandler{}) //所有未匹配到的路由都会匹配到跟路由
    mux.HandleFunc("bye",sayBye)

    log.Println("Starting server ... v2")
    log.Fatal(http.ListenAndServe(":4000",mux))
}
type myHandler struct {}
func (*myHandler) ServeHTTP(w http.ResponseWriter,r *http.Request){
    w.Write([]byte("Hello v2,the request url is:"+ r.URL.String()))
}
func sayBye(w http.ResponseWriter,r *http.Request){
    w.Write([]byte("Bye bye,this is version 2!"))
}
go run test.go
2018/07/09 15:50:23 Starting server ... v2

浏览器打开访问：http://localhost:4000/nihao 默认也匹配到/这里

如何自定义server信息呢？

import(
    "net/http"
    "log"
    "time"
)
func main(){
    server :=&http.Server{
        Addr: ":4000",
        WriteTimeout:2 * time.Second,
    }
    mux := http.NewServeMux()
    mux.Handle("/",&myHandler{}) //所有未匹配到的路由都会匹配到跟路由
    mux.HandleFunc("bye",sayBye)
    server.Handler=mux

    log.Println("Starting server ... v2")
    log.Fatal(server.ListenAndServe)
}
type myHandler struct {}
func (*myHandler) ServeHTTP(w http.ResponseWriter,r *http.Request){
    w.Write([]byte("Hello v2,the request url is:"+ r.URL.String()))
}
func sayBye(w http.ResponseWriter,r *http.Request){
    w.Write([]byte("Bye bye,this is version 2!"))
}
go run test.go
2018/07/09 15:57:46 Starting server ... v2
2018/07/09 15:57:46 0x120ef70
浏览器打开访问：http://localhost:4000 访问正常

客户端可以主动断开

package main
import(
    "net/http"
    "log"
    "time"
    "os"
    "os/signal"
)
func main(){
    server :=&http.Server{
        Addr: ":4000",
        WriteTimeout:4 * time.Second,
    }

    quit := make(chan os.Signal)
    signal.Notify(quit,os.Interrupt)

    mux := http.NewServeMux()
    mux.Handle("/",&myHandler{}) //所有未匹配到的路由都会匹配到跟路由
    mux.HandleFunc("bye",sayBye)
    server.Handler=mux

    go func(){
        <-quit
        if err:=server.Close(); err != nil {
            log.Fatal("Close server:",err)
        }
    }()

    log.Println("Starting server ... v3")
    err := server.ListenAndServe()
    if err !=nil{
        if err == http.ErrServerClosed{
            log.Print("Server closed under request")
        }else{
            log.Fatal("Server closed unexpected")
        }
    }
    log.Println("Server exit")
}
type myHandler struct {}
func (*myHandler) ServeHTTP(w http.ResponseWriter,r *http.Request){
    w.Write([]byte("Hello v2,the request url is:"+ r.URL.String()))
}
func sayBye(w http.ResponseWriter,r *http.Request){
    time.Sleep(3*time.Second)
    w.Write([]byte("Bye bye,this is version 2!"))
}
2018/07/09 20:53:41 Starting server ... v3 
此时暂停程序，ctrl+c
2018/07/09 20:54:01 Server closed under request
2018/07/09 20:54:01 Server exit

如何实现不同的路由转发呢？

package main

import (
    "log"
    "net/http"
    "time"
)

//创建一个map，进行路由的转发
var mux map[string]func(http.ResponseWriter, *http.Request)

func main() {
    server := http.Server{
        Addr:        ":8090",
        Handler:     &myHandler{},
        ReadTimeout: 5 * time.Second,
    }
    //通过路由注册，/hello 和 /bye 是不同的录用，调用不同的func
    mux = make(map[string]func(http.ResponseWriter, *http.Request)) //分配点内存空间
    mux["/hello"] = sayHello
    mux["/bye"] = sayBye
    err := server.ListenAndServe()
    if err != nil {
        log.Fatal(err)
    }
}

type myHandler struct{}

func (*myHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    if h, ok := mux[r.URL.String()]; ok { //map的妙用，判断有没有注册路由，如果有，找到，ok=true
        h(w, r)
        return
    }
}
func sayHello(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("Hello,this is version 3!"))
}
func sayBye(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("Bye,this is version 4!"))
}

go run test.go
浏览器访问：http://localhost:8090/hello
返回：Hello,this is version 3!
浏览器访问：http://localhost:8090/bye
返回：Bye,this is version 4!