expressmongotest/test/routes/middleware/load_article.js

var Article = require('../../data/models/article');

function loadArticle(req, res, next) {
  Article.findOne({title: req.params.title})
    .populate('author')
    .exec(function(err, article) {
      if (err) {
        return next(err);
      }
      if (! article) {
        return res.send('Not found', 404);
      }
      req.article = article;
      next();
    });
}

module.exports = loadArticle;