Node/Express.js request handling with different files - node.js

Question

//server.js
app.use('/shelf', require('./books').middleware);
//books.js
var app = new express.Router();
app.post('/books' , function (req, res) {
console.log('here');
});
module.exports = app;
This is what i did so far; my server runs under server.js, and when i make a '/shelf/books' request, it first goes to server.js and then to the books.js file and logs 'here'. but i want to add a request handler(a different file, handler.js i.e) where i want to to validate if the post param is a number and than redirect it to books.js if it is.

Answer 1

app.js
var express = require('express')
, http = require('http')
var app = express();
app.set('port', process.env.PORT || 3000);
app.set('view engine', 'jade');
app.use(express.favicon());
app.use(require('./handler').middleware);
http.createServer(app).listen(app.get('port'), function(){
console.log('Express server listening on port ' + app.get('port'));
});
handler.js
var express = require('express')
var books = require('./books')
var router = new express.Router();
router.get('/shelf/:book_id', function(req, res){
var onlyNumbers =req.param('book_id').match(/^\d+$/)
if (onlyNumbers){
var parsedNumber = parseInt(req.param('book_id'));
if( parsedNumber ) {
books(parsedNumber)
console.log("Parsed number is : " + parsedNumber)
res.end("Parsed number is : " + parsedNumber)
}
}
else {
console.log("not a number : " + req.param('book_id'))
res.end("not a number : " + req.param('book_id'))
}
res.end('');
})
module.exports = router;
books.js
var express = require('express')
var app = new express.Router();
module.exports = function(req, res) {
console.log("\t in books module")
};

Answer 2

How about this?
//handler.js
module.exports = function (req, res, next) {
req.check_result = /\d+/.test(req.body.yourfield);
};
// book.js
app.post('/books' , function (req, res) {
if(req.check_result) {
// your code
} else {
// your code
}
});
// server.js
app.use('/shelf', require('./handler'));
app.use('/shelf', require('./books').middleware);