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

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

/**
 * Alive协议处理器
 * 基于Clowire协议的变种
 */

const crc16 = require("../crc16");
const DATA_LENGTH = 9

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

module.exports = {
    /**
     * 收到tcp数据预处理
     * @param {Buffer} data 
     */
    handleRece: function (data) {
        // 大于9个字节超出alive数据帧取后9位,小于9位无效丢弃
        if (data.length > DATA_LENGTH) {
            data = data.slice(-DATA_LENGTH)
        } else if (data.length < DATA_LENGTH) {
            return
        }
        
        // Alive协议特殊标识检查
        if (data[0] !== 0xAA) return
        
        var crc = crc16(data.slice(1, -2));
        if (data.readUInt16LE(data.length - 2) === crc) {
            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 - 2) {
            return
        }
        
        var buffer = Buffer.alloc(data.length + 2);
        buffer[0] = 0xAA; // Alive协议标识
        for (let i = 0; i < data.length; i++) {
            buffer[i + 1] = data[i]
        }
        buffer.writeUInt16LE(crc16(data), data.length + 1)
        return buffer
    },
    
    /**
     * 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
    }
};