app.js

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
var ffmpeg = require('ffmpeg');
var childProcess = require('child_process');

var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');

var multer  = require('multer')
var upload = multer({ dest: 'public/images/uploads/', limits: { fileSize: 15000000}})

var app = express();

function runScript(req, callback) {

  // keep track of whether callback has been invoked to prevent multiple invocations
  var invoked = false;

  var process = childProcess.fork('squish.js', [`--file=${req.file.filename}`, `--type=${req.file.mimetype}`]);

  // listen for errors as they may prevent the exit event from firing
  process.on('error', function (err) {
      if (invoked) return;
      invoked = true;
      callback(err);
  });

  // execute the callback once the process has finished running
  process.on('exit', function (code) {
      if (invoked) return;
      invoked = true;
      var err = code === 0 ? null : new Error('exit code ' + code);
      callback(err);
  });

}

app.post('/upload', upload.single('file'), function (req, res, next) {
  runScript(req, function (err) {
    if (err) throw err;
    console.log('finished squishing!');
    var type = req.file.mimetype
    if (type == 'image/jpeg') {
      filetype = 'jpg'
    }
    if (type == 'image/png') {
      filetype = 'png'
    }
    if (type == 'image/gif') {
      filetype = 'gif'
    }
    if (type == 'video/quicktime') {
      filetype = 'mov'
    }
    res.redirect(`/images/squished/${req.file.filename}.${filetype}`)
});
})

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');

app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', indexRouter);
app.use('/users', usersRouter);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  next(createError(404));
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;