node-red-contrib-hasskit/hasskit/handleTcp.js

hasskit for node-red

const crc16 = function (data) {
    let tmp = 0
    for (let i of data) {
        tmp += i
    }
    return tmp & 0xff
}
const DATA_LENGTH = 8
const fns = {
    switch: require('./Switch'),
    climate: require('./Climate')
}
module.exports = {
    /**
     * 收到tcp数据预处理
     * @param {*} data 
     */
    handleRece: function (data) {
        //大于9个字节超出克伦威尔数据帧取后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
        }
        if (data[0] !== 0xb2 || data[DATA_LENGTH - 1] !== 0x2b)
            return
        var crc = crc16(data.slice(1, -2));
        if (data[DATA_LENGTH - 2] === crc) {
            return data
        }
        return
    },

    handle_write: function (buf) {

        let data = Buffer.from(buf)
        if (data.length < DATA_LENGTH) return
        data[6] = crc16(data.slice(1, -2))
        return data
    },
    getObjToBuf: function (domain) {
        return fns[domain].obj2buf
    },
    getBufToObj: function (domain) {
        return fns[domain].buf2obj
    }

}