NodeJS/Express app.use sequence and usage

Question

I tried to separate my node routing into two parts: HTML/App and REST. Here is what I've done:

app.js:

var appPort = process.env.PORT || 80;
var express = require('express');
var http = require('http');
var appRouter = require('./routes/index');
var restRouter = require('./routes/rest');
var app = express();
var srv = http.createServer(app);

app.set('port', appPort);
app.set('view engine', 'jade');
app.use(express.static(path.join(__dirname, 'public')));

app.use('/api/rest/', restRouter); // this seems not working .. I never get the expected response
app.use('/', appRouter);           // I get this even with localhost/api/rest/...

var server = srv.listen(app.get('port'), function() {
    debug('Express server listening  ' + server.address().address + ':' + server.address().port);
});

index.js:

var express = require('express');
var router = express.Router();

router.get('/*', function (req, res) {
    res.send('HOME')
});

module.exports = router;

rest.js

var express = require('express');
var router = express.Router();

router.get('/api/rest/*', function(req, res) {
    res.send('REST API');
});

module.exports = router;

My questions:
1. It's possible in general to build multiple routers in this way?
2. Does the sequence of get.use matter, and/or do I have to deal with 'next'?
3. In case I would like to access a database inside the router can I hand over a parameter like this:

// ...
var client  = new pg.Client(dbConnection);
// ...
app.use('/', appRouter(client));

Answer 1

1) It is possible to build multiple routers this way.

Because you are using this:

app.use('/api/rest/', restRouter);

your route calls in rest.js will be relative to /api/rest/ which means your code should be modified in rest.js to look like this:

router.get('*', function(req, res) {
    res.send('REST API');
});

I would also encourage you to see the Express multi-router example on GitHub. It illustrates this point very clearly by showing a REST app with versioned routes.

2) The order of things matter

See the Express documentation for app.use and you will note:

Middleware functions are executed sequentially, therefore the order of middleware inclusion is important.

If you reverse the order of your app.use calls, the router.get('/*', function (req, res) { line in index.js will catch everything before you get to other routes...defeating your purpose.

Also, if you don't call next , Express has no way to know that you are done or even that you want to continue to the next middleware or route.

3) The database question is a modules/scope question

This is more of a scope question than an Express question. I'd suggest looking up some of the excellent writing about javascript scope and also on how Node handles modules .