Proof-of-concept of node require hook to parse ROS messages

demo_poc.js

// Needs to have the messages and /tmp/genjs in NODE_PATH, so here's an sample invocation
//  NODE_PATH=$NODE_PATH:/opt/ros/indigo/share/:/tmp/genjs/ node demo_poc.js
// it also assumes that base_deserialize.js  base_serialize.js  find.js are copied to /tmp/genjs

require('./require_hook');

const stdString = require('std_msgs/msg/String');
console.log(`Loaded message ${stdString} ${stdString.datatype()}`);

const actionlibTutorialAveragingAction = require('actionlib_tutorials/msg/AveragingAction');
console.log(`Loaded message ${actionlibTutorialAveragingAction} ${actionlibTutorialAveragingAction.datatype()}`);

require_hook.js

const childProcess = require('child_process');
const genjsLocation = childProcess.execSync(`rospack find genjs`).toString().trim();
const genjsGeneratedPath = '/tmp/genjs/generated';

const loadRosMessage = function(m, filename) {
    const filenamePieces = filename.split('/');
    const messageName = filenamePieces[filenamePieces.length - 1].split('.')[0];
    const packageName = filenamePieces[filenamePieces.length - 3];
    const packageLocation = childProcess.execSync(`rospack find ${packageName}`).toString().trim();

    console.log(`Package location ${packageLocation}`);
    const includeString = `-I${packageName}:${packageLocation}/msg`;

    const compileCommand = ['python', `${genjsLocation}/scripts/gen_js.py`,
        filename, '-o', `${genjsGeneratedPath}/${packageName}`, '-p', packageName, includeString].join(' ');
    childProcess.execSync(compileCommand);

    return require.extensions['.js'](m, `${genjsGeneratedPath}/${packageName}/${messageName}.js`);
};

require.extensions['.msg'] = loadRosMessage;