Http Hijack longpolling

hijackclient.go

package main

import (
	"flag"
	"fmt"
	"net"
	"net/http"
	"net/http/httputil"
	"net/url"
	"time"
)

var (
	u = flag.String("url", "http://127.0.0.1:8080/hijack", "Connection URL")
)

func Connect(nurl *url.URL) {
	req := http.Request{
		Method: "GET",
		Header: http.Header{},
		URL:    nurl,
	}
	dial, err := net.Dial("tcp", nurl.Host)
	if err != nil {
		fmt.Println(err)
		return
	}
	clientconn := httputil.NewClientConn(dial, nil)
	clientconn.Do(&req)
	defer clientconn.Close()

	rwc, br := clientconn.Hijack()
	defer rwc.Close()

	for {
		buf := make([]byte, 100)
		s, err := br.Read(buf)
		if err != nil {
			fmt.Println("Read Err: " + err.Error())
		}
		fmt.Printf("size: %d, buf: %s\n", s, string(buf))
		time.Sleep(1 * time.Second)
		buf = nil
	}
	time.Sleep(5 * time.Second)
}

func main() {
	flag.Parse()
	nurl, _ := url.Parse(*u)
	Connect(nurl)
}

hijhackserver.go

package main

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

func main() {
	http.HandleFunc("/", hello)
	http.HandleFunc("/hijack", hijack)
	log.Println("Linsten on: 8080")
	http.ListenAndServe(":8080", nil)
}

func hijack(w http.ResponseWriter, r *http.Request) {
	hj, ok := w.(http.Hijacker)
	if !ok {
		http.Error(w, "webserver doesn't support hijacking", http.StatusInternalServerError)
		return
	}
	rwc, bufrw, err := hj.Hijack()
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	defer rwc.Close()
	if bufrw != nil {
		bufrw.Flush()
	}

	bufrw.WriteRune('\n') // 为什么必须要这句，如果没有client收不到数据

	count := 0
	for {
		count++
		bufrw.WriteString(strconv.Itoa(count))
		bufrw.WriteString(", Now we're speaking raw TCP. Say hi: ")
		bufrw.WriteString(time.Now().String())
		bufrw.Flush()
		time.Sleep(1 * time.Second)
	}
	time.Sleep(10 * time.Second)
}

func hello(w http.ResponseWriter, r *http.Request) {
	w.Write([]byte("hello, world\n"))
	w.Write([]byte(time.Now().String()))
}