func main() {
   // 對(duì)8080端口進(jìn)行監(jiān)聽(tīng)
   l, _ := net.Listen("tcp", ":8080")
   // 獲取和端口8080完成三次握手的tcp連接
   conn, _ := l.Accept()
   // 此時(shí)便能夠使用該連接和客戶端進(jìn)行通信
   data := make([]byte, 4096)
   // 可以從conn讀取數(shù)據(jù)緩沖區(qū)當(dāng)中
   conn.Read(data)
   // 將緩沖區(qū)的數(shù)據(jù)打印處理
   print(string(data))
}

type Conn interface {
   // Read reads data from the connection.
   // Read can be made to time out and return an error after a fixed
   // time limit; see SetDeadline and SetReadDeadline.
   Read(b []byte) (n int, err error)

   // Write writes data to the connection.
   // Write can be made to time out and return an error after a fixed
   // time limit; see SetDeadline and SetWriteDeadline.
   Write(b []byte) (n int, err error)

   // Close closes the connection.
   // Any blocked Read or Write operations will be unblocked and return errors.
   Close() error
}

type Conn struct {
   rwc     net.Conn
   // bufio.Reader 提供了緩存的功能，以及一些函數(shù)，方便我們解析HTTP請(qǐng)求體
   br      *bufio.Reader
   bw      *bufio.Writer
   // 是否已經(jīng)寫入響應(yīng)頭
   wroteHaeder bool
 }
 func NewConn(rwc net.Conn) *Conn {
   return &Conn{
      rwc:     rwc,
      br:      bufio.NewReader(rwc),
      bw:      bufio.NewWriter(rwc),
   }
}

type Request struct {
   // 存儲(chǔ)請(qǐng)求方法,上面例子便是GET 
   method string
   // 用于存儲(chǔ)請(qǐng)求的uri
   uri    string
   // 用于存儲(chǔ)http版本
   proto  string
   // http首部字段
   Header map[string]string
}

func (c *Conn) readRequest() (*Request, error) {
   req := NewRequest()
   // 現(xiàn)在只支持Get請(qǐng)求，讀取第一行內(nèi)容
   // GET /ping HTTP1.1
   line, err := c.br.ReadBytes('\n')
   if err != nil {
      return req, err
   }
   var f []string
   // 按空格來(lái)進(jìn)行分割,將請(qǐng)求行分割為三部分
   if f = strings.Split(string(line), " "); len(f) != 3 {
      return req, errors.New("http Header error")
   }
   // 獲取到GET, /ping, HTTP/1.1
   req.method, req.url, req.proto = f[0], f[1], f[2]
   // 解析請(qǐng)求體首部字段
   for {   
      line, err = c.br.ReadBytes('\n')
      if err != nil {
         return nil, err
      }
      // 當(dāng)讀取到空行時(shí)，說(shuō)明已經(jīng)首部字段已經(jīng)讀取完了
      if len(strings.TrimSpace(string(line))) == 0 {
         break
      }
      //舉例，讀取connection: keep-alive,獲取第一個(gè)空格的下標(biāo)
      i := bytes.IndexByte(line, ' ')
      if i == -1 {
         return nil, errors.New("header is error")
      }
      // 此時(shí)獲取到請(qǐng)求首部key，為connection
      key := string(line[:i-1])
      // 讀取到對(duì)應(yīng)的值，這里讀取到keep-alive
      value := strings.TrimSpace(string(line[i:]))
      // 簡(jiǎn)單讀取頭部字段即可
      req.Header[key] = value
   }
}

func main() {
   // 對(duì)8080端口進(jìn)行監(jiān)聽(tīng)
   l, _ := net.Listen("tcp", ":8080")
   // 獲取和端口8080完成三次握手的tcp連接
   conn, _ := l.Accept()
   // 獲取到conn連接
   c := NewConn(conn, handler)
   // 讀取到請(qǐng)求體
   req, _ := c.readRequest()
   if request.uri == "/hello" {
     ....
   }else{
     .... 
   }
 }

const (
   StatusOK = 200
)
var statusText = map[int]string{
   StatusOK:                   "OK",
}

// 返回響應(yīng)行
// 構(gòu)造響應(yīng)行 HTTP/1.1 200 OK
func (c *Conn) writeHeader(status int) error {
   if c.wroteHeader {
      return errors.New("code has been set")
   }
   c.wroteHeader = true
   var proto string
   //GET /hello HTTP/1.1
   proto = "HTTP/1.1"
   // 獲取文本描述,這里為OK
   text, ok := statusText[status]
   if !ok {
      text = "status code " + strconv.Itoa(status)
   }
   // 寫入數(shù)據(jù) HTTP1.1 200 OK\r\n
   c.bw.WriteString(proto + " " + strconv.Itoa(status) + " " + text + "\r\n")
   // 寫入空行
   c.bw.Write("\r\n")
   return nil
}
// 寫入響應(yīng)數(shù)據(jù)
func (c *Conn) WriteData(data []byte) error {
   // 還沒(méi)寫入請(qǐng)求頭 
   if !c.wroteHeader {
       //默認(rèn)狀態(tài)碼是200 OK
       c.writeHeader(StatusOK)
   }
   c.bw.Write(data)
   return nil
}

func main() {
   // 對(duì)8080端口進(jìn)行監(jiān)聽(tīng)
   l, _ := net.Listen("tcp", ":8080")
   // 獲取和端口8080完成三次握手的tcp連接
   conn, _ := l.Accept()
   // 獲取到conn連接
   c := NewConn(conn)
   // 讀取到請(qǐng)求體
   req, _ := c.readRequest()
   if request.uri == "hello" {
      c.WriteData("hello")
   }else{
      c.WriteData("hello world")
   }
   // 在最后,需要將緩沖區(qū)的數(shù)據(jù)進(jìn)行清空
   c.bw.Flush()
   // 因?yàn)轫憫?yīng)沒(méi)有設(shè)置content-length,所以只有連接斷開(kāi)后，
   // 瀏覽器才知道數(shù)據(jù)讀取完成了,此處需要斷開(kāi)連接
   c.rwc.Close()
 }