moleculer/src/serializers/protobuf.js

Fast & powerful microservices framework for Node.JS

/*
 * moleculer
 * Copyright (c) 2017 Ice Services (https://github.com/ice-services/moleculer)
 * MIT Licensed
 */


"use strict";

const BaseSerializer = require("./base");
const P = require("../packets");

/**
 * Protocol Buffer Serializer for Moleculer
 * 
 * https://github.com/google/protobuf
 * 
 * @class ProtoBufSerializer
 */
class ProtoBufSerializer extends BaseSerializer {

	/**
	 * Initialize Serializer
	 * 
	 * @param {any} broker
	 * 
	 * @memberOf Serializer
	 */
	init(broker) {
		super.init(broker);

		try {
			require("protobufjs/minimal");
		} catch(err) {
			/* istanbul ignore next */
			this.broker.fatal("The 'protobufjs' package is missing! Please install it with 'npm install protobufjs --save' command!", err, true);
		}

		this.packets = require("./proto/packets.proto.js").packets;		
	}	

	getPacketFromType(type) {
		switch(type) {
		case P.PACKET_EVENT: return this.packets.PacketEvent;
		case P.PACKET_REQUEST: return this.packets.PacketRequest;
		case P.PACKET_RESPONSE: return this.packets.PacketResponse;
		case P.PACKET_DISCOVER: return this.packets.PacketDiscover;
		case P.PACKET_INFO: return this.packets.PacketInfo;
		case P.PACKET_DISCONNECT: return this.packets.PacketDisconnect;
		case P.PACKET_HEARTBEAT: return this.packets.PacketHeartbeat;
		}
	}

	/**
	 * Serializer a JS object to string or Buffer
	 * 
	 * @param {Object} obj
	 * @param {String} type of packet
	 * @returns {String|Buffer}
	 * 
	 * @memberOf Serializer
	 */
	serialize(obj, type) {
		const p = this.getPacketFromType(type);	
		if (!p)
			/* istanbul ignore next */
			throw new Error("Invalid packet type!");

		const buf = p.encode(obj).finish();
		return buf.toString("binary");
	}

	/**
	 * Deserialize string/Buffer to JS object
	 * 
	 * @param {String|Buffer} str
	 * @param {String} type of packet
	 * @returns {Object}
	 * 
	 * @memberOf Serializer
	 */
	deserialize(str, type) {
		const p = this.getPacketFromType(type);	
		if (!p)
			/* istanbul ignore next */
			throw new Error("Invalid packet type!");

		const buf = Buffer.from(str, "binary");
		return p.decode(buf);
	}
}

module.exports = ProtoBufSerializer;