goProject/trunk/goutil/websocketUtil/model.go

package websocketUtil

import (
	"fmt"
	"time"

	"github.com/gorilla/websocket"
)

const (
	//  最大重试次数
	send_max_retry_num int = 60
	//  发送错误计数次数
	send_error_num int32 = 3
)

type model struct {
	wsurl   string
	msgChan chan *sendModel
	con     *websocket.Conn
	isclose bool
}

type sendModel struct {
	data     []byte
	sendType int
}

// 构造请求对象
func newModel(wsurl string) (*model, error) {
	result := &model{}
	result.wsurl = wsurl
	result.msgChan = make(chan *sendModel, 1000)

	// 创建连接
	err := result.createCon()
	if err != nil {
		return nil, err
	}

	go result.sendhandler()

	return result, nil
}

// 发送消息
func (this *model) send(st int, d []byte) {
	sm := &sendModel{
		data:     d,
		sendType: st,
	}
	this.msgChan <- sm
}

// 发送处理器
func (this *model) sendhandler() {
	defer func() {
		if rerr := recover(); rerr != nil {
			errLog("url:%s sendhandler recover:%s", this.wsurl, rerr)
		}
	}()

	//  下面逻辑需要考虑这些情况：
	//  1.对端重启 -> 需要尽可能保证消息投递成功
	//  2.对端永久关闭 -> 需要尽快释放channel里面的消息，以免堵塞channel，增加内占用
	var err error
	var errCount int32
	for {
		if this.isclose {
			return
		}

		sm := <-this.msgChan
		isOk := false
		for i := 0; i < send_max_retry_num; i++ {
			if this.isclose {
				return
			}

			if this.checkcon() == false {
				time.Sleep(time.Second * 1)
				debugLog("url:%s channel msgchen 数量达到%v", this.wsurl, len(this.msgChan))
				continue
			}

			err = this.con.WriteMessage(sm.sendType, sm.data)
			if err == nil {
				isOk = true
				break
			}

			//  记录错误日志
			errLog(fmt.Sprintf("wsurl:%s 发送数据错误 err:%s", this.wsurl, err))
			this.con = nil

			//  如果错误计数到达闸值，则不再重试
			if errCount >= send_error_num {
				break
			} else {
				time.Sleep(time.Second)
				continue
			}
		}

		//  修改错误计数
		if isOk == false {
			errCount = errCount + 1
		} else {
			errCount = 0
		}
	}
}

func (this *model) closeHandler(code int, text string) error {
	debugLog("websocketUtil.model 连接关闭 wsurl:%s  code:%v text:%s", this.wsurl, code, text)
	this.con = nil
	return nil
}

// 创建ws连接
func (this *model) createCon() error {
	dd := &websocket.Dialer{
		Proxy:            websocket.DefaultDialer.Proxy,
		HandshakeTimeout: 3 * time.Second,
	}
	ws, _, err := dd.Dial(this.wsurl, nil)
	if err != nil {
		return err
	}

	ws.SetCloseHandler(this.closeHandler)
	this.con = ws

	return nil
}

// 校验con是否可用
func (this *model) checkcon() bool {
	if this.con == nil {
		if err := this.createCon(); err != nil {
			errLog("wsurl:%s checkcon err:%s", this.wsurl, err)
			return false
		}
	}

	return true
}

//	close
//	@Description: 关闭连接
//	@receiver this *model
func (this *model) close() {
	close(this.msgChan)
	this.isclose = true
	debugLog("websocketUtil.model close wsurl:%s", this.wsurl)
}