domotz-remote-pawn/src/commands/tcpRequest.js

Domotz Agent

/** This file is part of Domotz Agent.
 * Copyright (C) 2016  Domotz Ltd
 *
 * Domotz Agent is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Domotz Agent is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Domotz Agent.  If not, see <http://www.gnu.org/licenses/>.
 **/
/**
 * Created by Georgi Tsatsev <gtsatsev@domotz.com> on 26/07/16.
 *
 */

const messageSizeLimit = Math.pow(2, 20);

var tcpRequest = function (message, resourceLocator) {
    var tcp = resourceLocator.net;
    var cmdUtils = resourceLocator.utils.command;

    var payload = message.payload;
    var host = payload.host;
    var port = payload.port;
    var msg = payload.message;
    var timeout = payload.timeout;
    var encoding = payload.encoding;
    var keepAlive = payload.await_timeout || payload.keepAlive;
    var entireMessage = '';
    var myConsole = resourceLocator.log.decorateLogs();

    return {
        execute: function (callback) {
            var id;
            var connection = tcp.createConnection(port, host, function () {
                connection.write(msg, encoding);
                myConsole.verbose('Message %s with encoding: %s, sent to %s:%d', msg.toString(encoding), encoding, host, port);
            });

            connection.on('close', function () {
                myConsole.debug('TCP connection to host %s closed', host);
            });

            connection.on('data', function (msg) {
                if (keepAlive === true) {
                    var msgLength = msg.length;
                    var entireMessageLength = entireMessage.length;
                    myConsole.debug('Received %d bytes', msgLength);
                    if (entireMessageLength + msgLength < messageSizeLimit) {
                        entireMessage += msg;
                        myConsole.debug('Keep alive, await more messages');
                    } else {
                        myConsole.error('Message overflow! Entire message becomes %d bytes.', entireMessageLength);
                        callback(
                            cmdUtils.getResponse(
                                null,
                                'Message limit of ' +
                                    messageSizeLimit +
                                    ' bytes was exceeded with ' +
                                    (entireMessageLength + msgLength - messageSizeLimit) +
                                    ' bytes.'
                            )
                        );
                        clearTimeout(id);
                        connection.destroy();
                    }
                } else {
                    myConsole.debug('Received %d bytes', msg.length);
                    myConsole.verbose('Message: %s', msg.toString(encoding));
                    callback(cmdUtils.getResponse(msg.toString(encoding), null));
                    clearTimeout(id);
                    connection.destroy();
                }
            });

            connection.on('error', function (error) {
                myConsole.error('TCP error - Error: {}' + error.message);
                myConsole.error(error.stack);
                callback(cmdUtils.getResponse(null, error));
                connection.destroy();
            });

            id = setTimeout(function () {
                if (keepAlive === true) {
                    myConsole.debug('Timeout expired');
                    callback(cmdUtils.getResponse(entireMessage.toString(encoding), null));
                } else {
                    myConsole.debug('TIMEOUT - Closed TCP connection after ' + timeout + ' milliseconds');
                    callback(cmdUtils.getResponse(null, 'Timeout'));
                }
                connection.destroy();
            }, timeout);
        },
        describe: function () {
            return message.correlationId + ' - tcpRequest - ' + host + ':' + port + ' - ' + message.length + ' packets';
        },
    };
};

module.exports.command = tcpRequest;