node-red-contrib-symi/lib/protocols/lf.js

Node-RED nodes for smart home device communication with Home Assistant integration, supporting HassKit, Clowire, Alive, LF and complete Symi protocols

/**
 * LF协议处理器
 * 另一种工业设备通信协议
 */

const DATA_LENGTH = 8

const fns = {
    switch: require('./lf/Switch'),
    climate: require('./lf/Climate')
}

module.exports = {
    /**
     * 收到tcp数据预处理
     * @param {Buffer} data 
     */
    handleRece: function (data) {
        // 大于8个字节超出LF数据帧取后8位,小于8位无效丢弃
        if (data.length > DATA_LENGTH) {
            data = data.slice(-DATA_LENGTH)
        } else if (data.length < DATA_LENGTH) {
            return
        }
        
        // LF协议简单校验
        if (data[0] === 0xFF && data[DATA_LENGTH - 1] === 0xFE) {
            return data
        }
    },

    /**
     * 处理写入数据
     * @param {Buffer|Array} buf 
     */
    handle_write: function (buf) {
        let data = Buffer.from(buf)
        if (data.length < DATA_LENGTH) return
        
        // LF协议添加帧头帧尾
        data[0] = 0xFF
        data[DATA_LENGTH - 1] = 0xFE
        return data
    },
    
    /**
     * 获取对象转缓冲区函数
     * @param {string} domain 
     */
    getObjToBuf: function (domain) {
        return fns[domain] ? fns[domain].obj2buf : null
    },
    
    /**
     * 获取缓冲区转对象函数
     * @param {string} domain 
     */
    getBufToObj: function (domain) {
        return fns[domain] ? fns[domain].buf2obj : null
    }
};