gosora/common/ws_user.go

package common

import (
	"errors"
	"sync"
	"time"

	"github.com/gorilla/websocket"
)

var ErrNoneOnPage = errors.New("This user isn't on that page")
var ErrInvalidSocket = errors.New("That's not a valid WebSocket Connection")

type WSUser struct {
	User    *User
	Sockets []*WSUserSocket
	sync.Mutex
}

type WSUserSocket struct {
	conn *websocket.Conn
	Page string
}

func (u *WSUser) Ping() error {
	var sockets []*WSUserSocket
	var del int
	func() {
		u.Lock()
		defer u.Unlock()
		for i, s := range u.Sockets {
			if s == nil || s.conn == nil {
				del++
				u.Sockets[i] = u.Sockets[len(u.Sockets)-del]
				continue
			}
			sockets = append(sockets, s)
		}
	}()
	if del > 0 {
		// TODO: Resize the capacity to release memory more eagerly?
		u.Sockets = u.Sockets[:len(u.Sockets)-del]
	}

	for _, s := range sockets {
		_ = s.conn.SetWriteDeadline(time.Now().Add(time.Minute))
		e := s.conn.WriteMessage(websocket.PingMessage, nil)
		if e != nil {
			s.conn.Close()
			u.Lock()
			s.conn = nil
			u.Unlock()
		}
	}

	return nil
}

func (u *WSUser) WriteAll(msg string) error {
	msgbytes := []byte(msg)
	for _, socket := range u.Sockets {
		if socket == nil {
			continue
		}
		w, e := socket.conn.NextWriter(websocket.TextMessage)
		if e != nil {
			return e
		}
		_, _ = w.Write(msgbytes)
		w.Close()
	}
	return nil
}

func (u *WSUser) WriteToPage(msg, page string) error {
	return u.WriteToPageBytes([]byte(msg), page)
}

// Inefficient as it looks for sockets for a page even if there are none
func (u *WSUser) WriteToPageBytes(msg []byte, page string) error {
	var success bool
	for _, socket := range u.Sockets {
		if socket == nil {
			continue
		}
		if socket.Page != page {
			continue
		}
		w, e := socket.conn.NextWriter(websocket.TextMessage)
		if e != nil {
			continue // Skip dead sockets, a dedicated goroutine handles those
		}
		_, _ = w.Write(msg)
		w.Close()
		success = true
	}
	if !success {
		return ErrNoneOnPage
	}
	return nil
}

// Inefficient as it looks for sockets for a page even if there are none
func (u *WSUser) WriteToPageBytesMulti(msgs [][]byte, page string) error {
	var success bool
	for _, socket := range u.Sockets {
		if socket == nil {
			continue
		}
		if socket.Page != page {
			continue
		}
		w, e := socket.conn.NextWriter(websocket.TextMessage)
		if e != nil {
			continue // Skip dead sockets, a dedicated goroutine handles those
		}
		for _, msg := range msgs {
			_, _ = w.Write(msg)
		}
		w.Close()
		success = true
	}
	if !success {
		return ErrNoneOnPage
	}
	return nil
}

func (u *WSUser) CountSockets() int {
	u.Lock()
	defer u.Unlock()
	return len(u.Sockets)
}

func (u *WSUser) AddSocket(conn *websocket.Conn, page string) {
	u.Lock()
	// If the number of the sockets is small, then we can keep the size of the slice mostly static and just walk through it looking for empty slots
	/*if len(u.Sockets) < 6 {
		for i, socket := range u.Sockets {
			if socket == nil {
				u.Sockets[i] = &WSUserSocket{conn, page}
				u.Unlock()
				//fmt.Printf("%+v\n", u.Sockets)
				return
			}
		}
	}*/
	u.Sockets = append(u.Sockets, &WSUserSocket{conn, page})
	//fmt.Printf("%+v\n", u.Sockets)
	u.Unlock()
}

func (u *WSUser) RemoveSocket(conn *websocket.Conn) {
	var del int
	u.Lock()
	defer u.Unlock()
	for i, socket := range u.Sockets {
		if socket == nil || socket.conn == nil {
			del++
			u.Sockets[i] = u.Sockets[len(u.Sockets)-del]
		} else if socket.conn == conn {
			del++
			u.Sockets[i] = u.Sockets[len(u.Sockets)-del]
			//break
		}
	}
	//Logf("%+v\n", u.Sockets)
	//Log("del: ", del)
	if del > 0 {
		// TODO: Resize the capacity to release memory more eagerly?
		u.Sockets = u.Sockets[:len(u.Sockets)-del]
	}
	//Logf("%+v\n", u.Sockets)
	return

	if len(u.Sockets) < 6 {
		for i, socket := range u.Sockets {
			if socket == nil {
				continue
			}
			if socket.conn == conn {
				u.Sockets[i] = nil
				//fmt.Printf("%+v\n", wsUser.Sockets)
				return
			}
		}
	}

	var key int
	for i, socket := range u.Sockets {
		if socket.conn == conn {
			key = i
			break
		}
	}
	u.Sockets = append(u.Sockets[:key], u.Sockets[key+1:]...)
	//fmt.Printf("%+v\n", u.Sockets)
}

func (u *WSUser) SetPageForSocket(conn *websocket.Conn, page string) error {
	if conn == nil {
		return ErrInvalidSocket
	}

	u.Lock()
	for _, socket := range u.Sockets {
		if socket == nil {
			continue
		}
		if socket.conn == conn {
			socket.Page = page
		}
	}
	u.Unlock()

	return nil
}

func (u *WSUser) InPage(page string) bool {
	u.Lock()
	defer u.Unlock()
	for _, socket := range u.Sockets {
		if socket == nil {
			continue
		}
		if socket.Page == page {
			return true
		}
	}
	return false
}

func (u *WSUser) FinalizePage(page string, h func()) {
	u.Lock()
	defer u.Unlock()
	for _, socket := range u.Sockets {
		if socket == nil {
			continue
		}
		if socket.Page == page {
			return
		}
	}
	h()
}