docs: function serveFileOrDie(req, res, gameInfo, cb) {
      var filePath, file;
  
      file = getFileFromReq(req, res);
      if (!file) return;
  
      if (file === '*') {
          zipResults(req, res, gameInfo);
          return;
      }
  
      // Build path to file.
      filePath = cb(file);
  
      fs.exists(filePath, function(exists) {
          if (!exists) {
              res.status(404).send('File not found: ' + file);
              return;
          }
          else {
              res.sendFile(filePath);
          }
      });
  }