pi-rfid-jukebox/player.js

const config = require('./config.json')

const glob = require('glob');
const spawn = require('child_process').spawn;
const tag_reader = spawn(config.tag_reader[0], config.tag_reader.slice(1));
const player = spawn(config.mpg321[0], config.mpg321.slice(1));

const express = require('express');
const logger = require('morgan')
const pug = require('pug');

var app = express();
var server = require('http').createServer();

const WebSocket = require('ws');
const WebSocketServer = WebSocket.Server;
var wss = new WebSocketServer({server: server});

var template = pug.compileFile(__dirname + '/source/templates/homepage.pug'),
    log_tpl = pug.compileFile(__dirname + '/source/templates/log.pug');

var play_log = [];

function exitHandler(options, err) {
  console.log('[player] closing children');
  if (err) console.log(err.stack);
  tag_reader.kill();
  player.kill();
  if (options.exit) {
    process.exit();
  }
}

process.on('exit', exitHandler.bind(null));
process.on('SIGINT', exitHandler.bind(null, {exit:true}));

tag_reader.on('error', function(err) {
  console.log(`[tag_reader] error=${err}`);
});

player.on('error', function(err) {
  console.log(`[mpg321] error=${err}`);
});

tag_reader.on('close', function(code, signal) {
  console.log(`[tag_reader] process closed:code=${code} signal=${signal}`);
});

player.on('close', function(code, signal) {
  console.log(`[mpg321] process closed:code=${code} signal=${signal}`);
});

// player.stdin.write("GAIN 100");

var last_tag = null;
var debounce_until = 0;

function lookup(tag, cb) {
  if (tag === config.stop_id) {
    return cb('STOP');
  }
  if (tag === config.pause_id) {
    return cb('PAUSE', 2);
  }

  glob('media/' + tag + ' - *.mp3', function(er, files) {
    if (files.length > 0) {
      appendLog(files[0]);
      return cb("LOAD " + files[0], 5);
    }
    appendLog(tag);
  });
}

function appendLog(message) {
  if (play_log.length > 10) {
    play_log.pop();
  }

  play_log.unshift(message);

  var data = {
    html: log_tpl({ play_log: play_log }),
    tag: last_tag
  };

  wss.broadcast(JSON.stringify(data));
}

function processLine(data) {
  if (Date.now() / 1000 < debounce_until) {
    return;
  }

  last_tag = String(data).trim();
  console.log("[tag] " + last_tag);

  // min 1 sec debounce
  debounce_until = Date.now() / 1000 + 1;

  lookup(last_tag, function(action, wait_sec) {
    wait_sec = wait_sec || 1;
    debounce_until = Date.now() / 1000 + wait_sec;
    if (action) {
      console.log(`[action] [${action}] for [${last_tag}]`);
      player.stdin.write(action + "\n");
    }
  });
}

tag_reader.stdout.on('data', (data) => {
  var s = data.toString(), lines = s.split(/\n/g);
  for (var i = 0, l = lines.length; i < l; i++) {
    processLine(lines[i]);
  }
});

tag_reader.stderr.on('data', (data) => {
  console.log(`[tag_reader:stderr] ${data}`);
});

player.stderr.on('data', (data) => {
  if (String(data).substr(0, 3) === "@F ") {
    return;
  }
  console.log(`[mpg321] stderr ${data}`);
});

app.use(logger('dev'))
app.use(express.static(__dirname + '/static'))

app.get('/', function (req, res, next) {
  try {
    var html = template({
      title: 'Home'
      , last_tag: last_tag
      , play_log: play_log
      , config: config
    })
    res.send(html)
  } catch (e) {
    next(e)
  }
});

wss.broadcast = function broadcast(data) {
  wss.clients.forEach(function each(client) {
    if (client.readyState === WebSocket.OPEN) {
      client.send(data);
    }
  });
};

wss.on('connection', function (ws) {
  console.log('[websocket] client connected');
  ws.on('close', function () {
    console.log('[websocket] client disconnected');
  });
});

server.on('request', app);

server.listen(config.port, function () {
  console.log('[http] listening on http://localhost:' + config.port)
})

// vim:ts=2 sw=2 et: