redirectToScreencast.js

function redirectToScreencast(req, res) {
  // alias the params so they are more terse to reference
  var screencastId = req.params.screencastId;
  var remoteAddress = req.connection.remoteAddress;
  var sql = squel.select()
    .from('screencasts')
    .where('screencastId = ?', screencastId)
    .toString();
  connection.queryAsync(sql).spread(function(screencasts) {
    var screencast = screencasts.shift();
    if (!screencast) {
      return res.status(404).send({error: 'sd'});
    }
    res.redirect(screencast.link);
    var sql = squel.select()
      .field('screencastId')
      .from('referrals')
      .where('screencastId = ? AND refereeRemoteAddress = ?', screencastId, remoteAddress)
      .toString();
    connection.queryAsync(sql).spread(function(referrals) {
      var alreadyCounted = referrals.length > 0;
      if (alreadyCounted) {
        // this user's view has already been counted - do not count it again!
        return;
      }
      connection.beginTransactionAsync().then(function() {
        var sql = squel.update()
          .table('screencasts')
          .set('referralCount = referralCount + 1')
          .where('screencastId = ?', screencastId)
          .toString();
        return connection.queryAsync(sql);
      }).then(function() {
        var sql = squel.insert()
          .into('referrals')
          .set('screencastId', screencastId)
          .set('refereeRemoteAddress', remoteAddress)
          .toString();
        return connection.queryAsync(sql);
      }).then(function() {
        return connection.commit();
      }).error(function() {
        return connection.rollback();
      });
    });
  });
}