conn.go

package websocket

import (
	"encoding/json"
	"github.com/gobwas/ws"
	"net"
	"net/url"
	"sync"
	"time"
)

// Conn websocket connection
type Conn struct {
	id     string
	conn   net.Conn
	params url.Values
	done   chan bool
	mu     sync.Mutex
}

var pingHeader = ws.Header{
	Fin:    true,
	OpCode: ws.OpPing,
	Masked: false,
	Length: 0,
}

var PingInterval = time.Second * 5

const TextMessage = false

// ID return an connection identifier (could be not unique)
func (c *Conn) ID() string {
	return c.id
}

// Emit message to connection.
func (c *Conn) Emit(name string, data interface{}) error {
	var msg = struct {
		Name string      `json:"name"`
		Data interface{} `json:"data"`
	}{
		Name: name,
		Data: data,
	}

	b, err := json.Marshal(msg)
	if err != nil {
		return err
	}

	opCode := ws.OpBinary
	if TextMessage {
		opCode = ws.OpText
	}
	h := ws.Header{
		Fin:    true,
		OpCode: opCode,
		Masked: false,
		Length: int64(len(b)),
	}

	return c.Write(h, b)
}

// Write byte array to connection.
func (c *Conn) Write(h ws.Header, b []byte) error {
	c.mu.Lock()
	defer c.mu.Unlock()

	_ = c.conn.SetWriteDeadline(time.Now().Add(15000 * time.Millisecond))
	err := ws.WriteHeader(c.conn, h)
	if err != nil {
		return err
	}

	_, err = c.conn.Write(b)
	return err
}

// Send data to connection.
func (c *Conn) Send(data any) error {
	var b []byte

	switch data.(type) {
	case []byte:
		b = data.([]byte)
	default:
		b, _ = json.Marshal(data)
	}

	opCode := ws.OpBinary
	if TextMessage {
		opCode = ws.OpText
	}
	h := ws.Header{
		Fin:    true,
		OpCode: opCode,
		Masked: false,
		Length: int64(len(b)),
	}

	return c.Write(h, b)
}

// Close closing websocket connection.
func (c *Conn) Close() error {
	c.mu.Lock()
	defer c.mu.Unlock()

	if c.conn == nil {
		return nil
	}

	c.done <- true

	err := c.conn.Close()
	c.conn = nil

	return err
}

// Param gets the value from url params.
// If there are no values associated with the key, Get returns
// the empty string. To access multiple values, use the map
// directly.
func (c *Conn) Param(key string) string {
	return c.params.Get(key)
}

func (c *Conn) startPing() {
	ticker := time.NewTicker(PingInterval)

	go func() {
		for {
			select {
			case <-ticker.C:
				if err := c.Write(pingHeader, nil); err != nil {
					_ = c.Close()
				}
			case <-c.done:
				ticker.Stop()
				return
			}
		}
	}()
}