Routes also have the .param method to allow for easier resource loading in this case we will make sure all our routes load the post

express-routes-params.js

// vendor
var express = require('express');
 
var router = new express.Router();
 
// routes also have the .param method to allow for easier resource loading
// in this case we will make sure all our routes load the post
router.param('post_id', function(req, res, next, post_id) {
    // simulate loading a post
    setTimeout(function() {
        req.post = { name: 'foo' };
        next();
    }, 1000);
});
 
router.get('/:post_id', function(req, res, next) {
    res.send(req.post.name + '\n');
});
 
router.post('/:post_id/comment', function(req, res, next) {
    // we could add the comment to req.post here
    res.send('\\o/\n');
});
 
module.exports = router;