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

hasskit for node-red

const crc16 = require("./crc16");
const DATA_LENGTH = 9
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
        }
        var crc = crc16(data.slice(0, -3));
        if (data.readUInt16LE(data.length - 3, data) === crc) {
            return data
        }
    },

    handle_write: function (buf) {
        let data = Buffer.from(buf)
        if (data.length < DATA_LENGTH - 3) {
            return
        }
        var buffer = Buffer.alloc(data.length + 3);
        for (let i = 0; i < data.length; i++) {
            buffer[i] = data[i]
        }
        buffer.writeUInt16LE(crc16(data), data.length)
        buffer[buffer.length - 1] = 0xaa
        return buffer
    },
    getObjToBuf: function (domain) {
        return fns[domain].obj2buf
    },
    getBufToObj: function (domain) {
        return fns[domain].buf2obj
    }
}