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@hellojukay
Last active May 12, 2022 08:39
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A http(s) proxy server
package main
import (
"bytes"
"fmt"
"io"
"log"
"net"
"regexp"
"strings"
"sync"
"time"
)
var (
// 主要为了降低 GC 压力
bytesPool = sync.Pool{
New: func() interface{} {
var buffer = bytes.NewBuffer(make([]byte, 2048))
return buffer
},
}
)
func NewBufferFromPool() *bytes.Buffer {
return bytesPool.Get().(*bytes.Buffer) // 通过Get来获得一个
}
func main() {
l, err := net.Listen("tcp4", ":8080")
if err != nil {
log.Print(err)
return
}
for {
conn, err := l.Accept()
if err != nil {
log.Print(err)
continue
}
var method = make([]byte, 20)
var path = make([]byte, 2048)
var protocol = make([]byte, 10)
_, err = fmt.Fscanf(conn, "%s%s%s", &method, &path, &protocol)
if err != nil {
log.Print(err)
continue
}
firstLine := fmt.Sprintf("%s %s %s", string(method), string(path), string(protocol))
log.Print(firstLine)
targetHost, targetPort := parseHost(string(path))
go proxy(conn, targetHost, targetPort, firstLine, string(method))
}
}
func parseHost(path string) (string, string) {
if !strings.HasPrefix(path, "http") {
hostPath := strings.Split(path, ":")
return hostPath[0], hostPath[1]
}
re := regexp.MustCompile("/+")
hostPath := re.Split(path, -1)[1]
tmp := strings.Split(hostPath, ":")
if len(tmp) < 2 {
return tmp[0], "80"
}
return tmp[0], tmp[1]
}
func proxy(conn net.Conn, host string, port string, firstLine string, method string) {
s, err := net.DialTimeout("tcp4", fmt.Sprintf("%s:%s", host, port), time.Duration(1)*time.Second)
if err != nil {
log.Print(err)
return
}
if method != "CONNECT" {
s.Write([]byte(firstLine))
} else {
var buffer = make([]byte, 1024)
_, err := conn.Read(buffer)
if err != nil {
log.Print(err)
}
conn.Write([]byte("HTTP/1.1 200 Connection Established\r\n"))
conn.Write([]byte("Proxy-agent: golang\r\n"))
conn.Write([]byte("\r\n"))
}
var clientBuffer = NewBufferFromPool().Bytes()
var serverBuffer = NewBufferFromPool().Bytes()
go func() {
defer s.Close()
defer log.Printf("%s finished", firstLine)
var n int
for {
n, err = s.Read(serverBuffer)
if err == io.EOF {
break
}
if n == 0 {
time.Sleep(time.Millisecond * time.Duration(100))
continue
}
conn.Write(serverBuffer[:n])
}
}()
go func() {
defer conn.Close()
var n int
for {
n, err = conn.Read(clientBuffer)
if err == io.EOF {
break
}
if n == 0 {
time.Sleep(time.Millisecond * time.Duration(100))
continue
}
s.Write(clientBuffer[:n])
}
}()
}
@hellojukay
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@yidigo 你是对的

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