Go編程基礎4-Http服務器

一、http服務器

package main
import(
    "net/http"
    "log"
)
func main(){//註冊某個函數專門響應某個路由"/"，函數簽名符合
    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

瀏覽器打開訪問：http://localhost:4000/

瀏覽器打開訪問：http://localhost:4000/bye

如何使用mux自定義ServeHTTP，實現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

瀏覽器打開訪問：http://localhost:4000/

瀏覽器打開訪問：http://localhost:4000/bye

瀏覽器打開訪問：http://localhost:4000/abcdef 默認也匹配到這裏

全部未匹配到的路由都會匹配到跟 "/" 路由

package main
import(
    "net/http"
    "log"
)
func main(){
    mux := http.NewServeMux()
    mux.Handle("/",&myHandler{}) //全部未匹配到的路由都會匹配到跟路由
    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

瀏覽器打開訪問：http://localhost:4000/nihao 默認也匹配到/這裏

如何自定義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{}) //全部未匹配到的路由都會匹配到跟路由
    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
瀏覽器打開訪問：http://localhost:4000 訪問正常

客戶端能夠主動斷開

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{}) //全部未匹配到的路由都會匹配到跟路由
    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 
此時暫停程序，ctrl+c
2018/07/09 20:54:01 Server closed under request
2018/07/09 20:54:01 Server exit

如何實現不一樣的路由轉發呢？

package main

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

//建立一個map，進行路由的轉發
var mux map[string]func(http.ResponseWriter, *http.Request)

func main() {
    server := http.Server{
        Addr:        ":8090",
        Handler:     &myHandler{},
        ReadTimeout: 5 * time.Second,
    }
    //經過路由註冊，/hello 和 /bye 是不一樣的錄用，調用不一樣的func
    mux = make(map[string]func(http.ResponseWriter, *http.Request)) //分配點內存空間
    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，判斷有沒有註冊路由，若是有，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
瀏覽器訪問：http://localhost:8090/hello
返回：Hello,this is version 3!
瀏覽器訪問：http://localhost:8090/bye
返回：Bye,this is version 4!