第一個go websocket程式，使用github.com/gorilla/websocket框架

命令匯入：go get github.com/gorilla/websocket

具體程式碼幾乎都是拷貝網友的，東拼西湊的，先跑起來，具體再慢慢研究

package main
import (
   "fmt"
   "github.com/gorilla/websocket"
   "net/http"
   _ "net/http"
)
var upgrader = websocket.Upgrader{
   CheckOrigin: func(r *http.Request) bool{
      return true
 
   },
}

func main() {
   http.HandleFunc("/echo", func(w http.ResponseWriter, r *http.Request) {
      c, err := upgrader.Upgrade(w, r, nil)
      if err != nil {
         fmt.Print("upgrade:", err)
         return
      }
      for {
         mt, message, err := c.ReadMessage()
         if err != nil {
            fmt.Println("read:", err)
 
            break
         }
         fmt.Printf("recv: %s", message)
         err = c.WriteMessage(mt, message)
         if err != nil {
            fmt.Println("write:", err)
            break
         }
      }
   })

   http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
      http.ServeFile(w, r, "websockets.html") //自己建立個html
 
   })

   http.ListenAndServe(":8011", nil)
}