HTTP server challenge entry

server.go

package main
import (
  "net"
  "regexp"
  "fmt"
  "bufio"
  "bytes"
)
func main() {
  get_parser := regexp.MustCompile("[\\?&]value=([^& ]+)*")
  sock, _ := net.ListenTCP("tcp",&net.TCPAddr{net.ParseIP("127.0.0.1"),8040})
  fmt.Println("Listening")
  for {
    connection,er := sock.AcceptTCP()
    if er == nil { 
      go handler(connection, get_parser) 
    }
  }
}
func handler(conn net.Conn, re *regexp.Regexp) {
  get_match := []byte("GET")
  buf := bufio.NewReader(conn)
  defer conn.Close()
  read := true
  for read {
    ln, _, er := buf.ReadLine()
    read = er == nil
    
    if !bytes.Equal(ln[:3],get_match) { 
      continue 
    }
    
    match := re.FindSubmatch([]uint8(ln))
    var response, entity []byte
    if len(match) > 0 {
      response = []byte(fmt.Sprintf("HTTP/1.1 200 OK\r\nContent-length: %v\r\n\r\n",len(match[1])))
      entity = match[1]
    } else {
      response = []byte("HTTP/1.1 400 Bad Request\r\nContent-length: 5\r\n\r\n")
      entity = []byte("error")
    }
    conn.Write(response)
    conn.Write(entity)
  }
}