Golang HTTP connection reuse method

Time:2019-12-6

Server terminal

Golang httpserver enables the keepalive connection reuse option by default

The handler function needs to read the body data completely and construct the return message. Otherwise, when the data cannot be sent at one time, the connection multiplexing will fail.

Examples are as follows


package main
 
import (
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"strconv"
	"strings"
	"time"
)
 
func connHandler(w http.ResponseWriter, r *http.Request) {
	// parse
	r.ParseForm()
	response_time := r.Header.Get("sleep-time")
	// <= NOTE
	if _, err := ioutil.ReadAll(r.Body); err != nil {
		http.Error(w, err.Error(), 500)
		return
	}
	defer r.Body.Close()
	// sleep for some time
	resp_time := 1
	if response_time != "" {
		ms, _ := strconv.ParseFloat(response_time, 64)
		resp_time = (int)(ms * 1000)
	}
	time.Sleep(time.Duration(resp_time) * time.Millisecond)
	// parepare response
	status := 200
	body := ""
	w.Header().Set("Content-Type", "text/plain")
	w.Header().Set("Content-Length", strconv.Itoa(len(body)))
	w.WriteHeader(status)
	w.Write([]byte(body))
}
 
func main() {
	http.HandleFunc("/", connHandler)
	if err := http.ListenAndServe(":server_port", nil); err != nil {
		log.Fatal("ListenAndServe: ", err)
	}
}

Client terminal

The client needs to build a global client, read the response body completely, and close the body


package main

import (
  "bytes"
  "fmt"
  "io"
  "io/ioutil"
  "log"
  "net/http"
  "time"
)

var (
  httpClient *http.Client
)

const (
  MaxIdleConnections int = 20
  RequestTimeout   int = 30
)

// init HTTPClient
func init() {
  httpClient = createHTTPClient()
}

// createHTTPClient for connection re-use
func createHTTPClient() *http.Client {
  client := &http.Client{
   Transport: &http.Transport{
      MaxIdle  ConnsPerHost: MaxIdleConnections,
 },
 Timeout: time.Duration(RequestTimeout) * time.Second,
  }
  return client
}

func conn_reuse_post(conn_reuse_times int) {
  var endPoint string = "http://server_ip:server_port/"
  data := []byte{}
  // fill data 
  for i := 0; i < conn_reuse_times; i++ {
 // use global httpClient to send request
 resp, err := httpClient.Post(endPoint, "application/x-www-form-urlencoded", bytes.NewBuffer([]byte(data)))
 fmt.Println(resp)
 if err != nil {
   log.Println("err", err)
   return
 }
 io.Copy(ioutil.Discard, resp.Body) // <= NOTE
 resp.Body.Close()  // <= NOTE
  }
}

func main() {
  conn_reuse_post(5)
}

The above gorang HTTP connection reuse method is all that Xiaobian has shared with you. I hope it can give you a reference, and I hope you can support developepaer more.