domotz-remote-pawn/src/network_tools/fingJamDevices.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 Iacopo Papalini <iacopo@domotz.com> on 08/09/16.
 *
 * You need fing installed on the device in order to enable the device
 * network jamming
 */
const JAMMED_FILE_NAME = "jammed.txt";
const LOG_PREFIX = "FING_JAM_DEVICES - ";

var jamDevicesFileManager = function (macListFile) {
    "use strict";
    var fs = require('fs');
    var previousMacAddresses = [];

    function listChanged(macAddresses) {
        if (macAddresses.length !== previousMacAddresses.length) {
            return true;
        }
        else {
            for (var i = macAddresses.length; i-- > 0;) {
                if (macAddresses[i] !== previousMacAddresses[i]) {
                    return true;
                }
            }
        }
        return false;
    }

    function writeFile(contents) {
        console.debug(LOG_PREFIX + 'Synchronously writing file %s', macListFile);
        try {
            fs.writeFileSync(macListFile, contents + '\n');
            console.debug(LOG_PREFIX + 'File written %s (%s)', macListFile, JSON.stringify(contents));
            return contents.length > 0;
        } catch (e) {
            console.error("Cannot write file %s, killing fing", macListFile);
            return false;
        }
    }

    function writeFileIfListChanged(macAddresses) {
        /**
         * Using the macAddresses list, writes its contents in the macListFile.
         * @returns boolean true if the fing process should run after the update
         */
        if (listChanged(macAddresses)) {
            console.info(LOG_PREFIX + "Jammed device list changed");
        } else {
            return macAddresses.length > 0;
        }
        previousMacAddresses = macAddresses;

        var contents = macAddresses.join('\n');
        return writeFile(contents);
    }

    return {
        write: writeFileIfListChanged
    };
};


var fingProcessManager = function (fingCommand, macListFile, childProcess) {
    "use strict";
    var fingProcess = null;
    var fingParameters = ["--kickout", '-', '--kocfg', macListFile].join(' ');

    function isFingRunning() {
        if (fingProcess !== null) {
            console.debug(LOG_PREFIX + "Fing process is running");
            return true;
        } else {
            console.debug(LOG_PREFIX + "Fing process not existing");
            return false;
        }
    }

    function assureFingIsRunning() {
        if (!isFingRunning()) {
            console.info(LOG_PREFIX + 'Starting fing');
            fingProcess = childProcess.exec(fingCommand + " " + fingParameters + " " + " >/dev/null");
            fingProcess.on('exit', function (code, signal) {
                fingProcess = null;
                console.info(LOG_PREFIX + "Fing process exited with %s", code || signal);
            });
        } else {
            console.debug(LOG_PREFIX + "Fing already running, not executed");
        }
    }

    function assureFingIsNotRunning() {
        if (isFingRunning()) {
            console.info(LOG_PREFIX + 'Killing fing');
            fingProcess.kill();
        } else {
            console.info(LOG_PREFIX + "Fing not running, not killing it");
        }
    }

    return {
        assureFingIsRunning: assureFingIsRunning,
        assureFingIsNotRunning: assureFingIsNotRunning
    };
};


var fingWrapper = function (childProcess, engineRequest) {
    "use strict";
    var env = process.env;
    var macListFile = (env.DOMOTZ_ROOT_DIR || '/opt/domotz') + "/etc/" + JAMMED_FILE_NAME;
    var fingCommand = (env.FING_BINARY_FULL_PATH || '/usr/bin/fing');
    var fileWriter = jamDevicesFileManager(macListFile);
    var processManager = fingProcessManager(fingCommand, macListFile, childProcess);

    function handleServerResponse(data) {
        var shouldRun = fileWriter.write(data);
        if (shouldRun) {
            processManager.assureFingIsRunning();
        }
        else {
            processManager.assureFingIsNotRunning();
        }
    }

    return {
        updateMacAddresses: function () {
            console.info(LOG_PREFIX + "Updating mac addresses list");

            engineRequest.sendWithPromise('/device/jammed', 'GET').
                then(function (data) {
                    handleServerResponse(data);
                }).
                catch(function () {
                    console.error(LOG_PREFIX + 'Cannot update list, assuming no device to jam');
                    handleServerResponse([]);
                });
        }
    };
};

module.exports.fingWrapper = fingWrapper;

// For testing purposes only
module.exports._fileManager = jamDevicesFileManager;
module.exports._fingProcessManager = fingProcessManager;