net/http workshop

01_ListenAndServe.go

package main

import (
	"fmt"
	"io"
	"log"
	"net/http"
)

func Handler(w http.ResponseWriter, req *http.Request) {
	str := fmt.Sprintln(req)
	io.WriteString(w, str)
}

func main() {
	http.HandleFunc("/", Handler)
	err := http.ListenAndServe(":8000", nil)
	if err != nil {
		log.Fatal("ListenAndServe: ", err)
	}
}

02_Serve.go

package main

import (
	"fmt"
	"io"
	"log"
	"net"
	"net/http"
)

func Handler(w http.ResponseWriter, req *http.Request) {
	str := fmt.Sprintln(req)
	io.WriteString(w, str)
}

func main() {
	http.HandleFunc("/", Handler)

	listener, err := net.Listen("tcp", ":8001")
	err = http.Serve(listener, nil)
	if err != nil {
		log.Fatal("ListenAndServe: ", err)
	}
}

03_01_Handler.go

package main

import (
	"fmt"
	"io"
	"log"
	"net/http"
)

type MyHandler int64

func (h MyHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	h++
	io.WriteString(w, fmt.Sprintf("counter = %d", h))
}

func main() {
	handler := MyHandler(0)
	err := http.ListenAndServe(":8002", handler)
	if err != nil {
		log.Fatal("ListenAndServe: ", err)
	}
}

03_Handler.go

package main

import (
	"fmt"
	"io"
	"log"
	"net/http"
)

type MyHandler int64

func (h *MyHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	//log.Println(req.URL.Path)
	*h++
	io.WriteString(w, fmt.Sprintf("counter = %d", *h))
}

func main() {
	handler := MyHandler(0)
	err := http.ListenAndServe(":8002", &handler)
	if err != nil {
		log.Fatal("ListenAndServe: ", err)
	}
}

04_ServeMux.go

package main

import (
	"fmt"
	"io"
	"log"
	"net/http"
)

var counter int64

type MyIncrementer struct {
}

func (c *MyIncrementer) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	//log.Println(req.URL.Path)
	counter++
	io.WriteString(w, fmt.Sprintf("counter = %d", counter))
}

type MyDecrementer struct {
}

func (d *MyDecrementer) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	//log.Println(req.URL.Path)
	counter--
	io.WriteString(w, fmt.Sprintf("counter = %d", counter))
}

type MyThrough struct {
}

func (d *MyThrough) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	//log.Println(req.URL.Path)
	// do nothing
	io.WriteString(w, fmt.Sprintf("counter = %d", counter))
}

func main() {
	incr := &MyIncrementer{}
	decr := &MyDecrementer{}
	through := &MyThrough{}
	mux := http.NewServeMux()
	mux.Handle("/", decr) // 人生は減点法です
	mux.Handle("/incr", incr)
	mux.Handle("/decr", decr)
	//mux.Handle("/favicon.ico", through)

	err := http.ListenAndServe(":8003", mux)
	if err != nil {
		log.Fatal("ListenAndServe: ", err)
	}
}