knxultimate/src/protocol/KNXConnectResponse.ts

KNX IP protocol implementation for Node. This is the ENGINE of Node-Red KNX-Ultimate node.

/**
 * Parses KNX connect response frames.
 *
 * Written in Italy with love, sun and passion, by Massimo Saccani.
 *
 * Released under the MIT License.
 * Use at your own risk; the author assumes no liability for damages.
 */

import CRD from './CRD'
import HPAI from './HPAI'
import { KNX_CONSTANTS } from './KNXConstants'
import KNXPacket from './KNXPacket'

export default class KNXConnectResponse extends KNXPacket {
	channelID: number

	status: number

	hpai: HPAI | null

	crd: CRD | null

	constructor(
		channelID: number,
		status: number,
		hpai: HPAI | null,
		crd: CRD | null,
	) {
		super(
			KNX_CONSTANTS.CONNECT_RESPONSE,
			hpai == null ? 2 : 2 + hpai.length + crd.length,
		)
		this.channelID = channelID
		this.status = status
		this.hpai = hpai
		this.crd = crd
	}

	static createFromBuffer(
		buffer: Buffer,
		offset: number = 0,
	): KNXConnectResponse {
		if (offset + 2 > buffer.length) {
			throw new Error('Buffer too short')
		}
		const channelID = buffer.readUInt8(offset++)
		const status = buffer.readUInt8(offset++)
		let hpai: HPAI | null
		let crd: CRD | null
		if (offset < buffer.length) {
			hpai = HPAI.createFromBuffer(buffer, offset)
			offset += hpai.length
			crd = CRD.createFromBuffer(buffer, offset)
		}
		return new KNXConnectResponse(channelID, status, hpai, crd)
	}

	static statusToString(status: number): string {
		switch (status) {
			case KNX_CONSTANTS.E_SEQUENCE_NUMBER:
				return 'Invalid Sequence Number'
			case KNX_CONSTANTS.E_CONNECTION_TYPE:
				return 'Invalid Connection Type'
			case KNX_CONSTANTS.E_CONNECTION_OPTION:
				return 'Invalid Connection Option'
			case KNX_CONSTANTS.E_NO_MORE_CONNECTIONS:
				return 'No More Connections'
			case KNX_CONSTANTS.E_NO_MORE_UNIQUE_CONNECTIONS:
				return 'No More Unique Connections'
			case KNX_CONSTANTS.E_DATA_CONNECTION:
				return 'Invalid Data Connection'
			case KNX_CONSTANTS.E_KNX_CONNECTION:
				return 'Invalid KNX Connection'
			case KNX_CONSTANTS.E_TUNNELING_LAYER:
				return 'Invalid Tunneling Layer'
			default:
				return `Unknown error ${status}`
		}
	}

	toBuffer(): Buffer {
		const buffer = Buffer.alloc(2)
		buffer.writeUInt8(this.channelID, 0)
		buffer.writeUInt8(this.status, 1)
		if (this.hpai == null) {
			return buffer
		}
		return Buffer.concat([
			buffer,
			this.hpai.toBuffer(),
			this.crd.toBuffer(),
		])
	}
}