Guidance NPM | npm.io

Guidance

A Rails like middleware for routes loading on expressjs applications. (heavily inspired from http://guides.rubyonrails.org/routing.html)

Purposes & use

This module provide a Rails like approach for defining routes. It also add helpers for the views appending it to the res.locals object.

Required configuration:

First of all define your controllers. They are simple exported objects where the filename is the controller name, object keys are the controller's actions, and the object values are the route handlers. Default location of the controllers is process.cwd() + '/controllers'

// controllers/welcomeController.js

module.exports = {
  index: function(req, res) {
    return res.json({ hello: 'welcome' });
  },
  about: function(req, res) {
    return res.json({ hi: 'this is guidance' });
  }
};

Routes should be defined as a module that exports a function accepting the router object as parameter. Use the router object to define your routes.

Define your routes like this (usually in a separated routes.js file):

// routes.js
module.exports = function(router) {
  router.get('/', { to: 'welcome#index' });
  router.get('/about', { to: 'welcome#about' });
};

This snippets indicate that on GET / the express app respond with welcome controller's index action, and GET /about is mapped to the welcome controller's about action.

Finally use the middleware like this:

const express = require('express');
const guidance = require('guidance');
const routes = require('routes'); // the module defined above (routes.js)

const app = express();
app.use(guidance.initialize(routes));

...

Naming conventions

Some conventions are adopted for the correct mapping of the routes.

controllers

When referring to a controller name, the controller file is resolved to <controllersPath>/<controllerName>.js where:

controllersPath is default to process.cwd() + '/controllers' (overridable with guidance.initialize options).
controllerName resolves to the controller name without an eventual Controller suffix (welcomeController and welcome both becomes welcome)

actions

When referring to an action name, the action handler is mapped to the relative controller's property with the same name. An eventual Action suffix is removed from the name (indexAction and index both becomes index)

The controller's property should be obviously a callable.

Reference

Guidance

guidance.initialize(routes, options)

guidance middleware.

Accepted parameters:

routes the defined routes module
options.controllersDir the absolute path where to locate the controller modules. Defaults to process.cwd() + '/controllers'

Router

Basic routing

Connect URLs to code in the following way (using the to key)

router.get('/home', { to: 'welcome#index' })
router.post('/login', { to: 'session#create' })

When the express app receive a GET /home request, the index action handler of the welcome controller is used; the express app responds also on POST /login with the session controller's create action.

Any express supported method (router.METHOD) can be used.

Root

You can specify how to route GET / with the root method:

router.root({ to: 'welcome#index' })
router.root('welcome#index') // shortcut for the above

Named parameters

Named parameters are also supported:

router.get('/patients/:id', { to: 'patients#show' })

the id parameter is available to the req.params object of the action.

Named routes (views helpers)

A name can be assigned to the route (using the as key):

router.get('/hp', { to: 'welcome#homepage', as: 'homepage' });
router.get('/patients/:id', { to: 'patients#show', as 'patient' })

This helpers are available to the views:

homepage()  // returns '/hp'
patient(42) // returns '/patients/42'

Resources

Resources can also be defined:

router.resources('photos')

This statement creates the following routes:

GET /photos to photos#index
GET /photos/new to photos#new
POST /photos to photos#create
GET /photos/:id to photos#show with id as parameter
GET /photos/:id/edit to photos#edit with _id as parameter
PATCH /photos/:id to photos#update with _id as parameter
PUT /photos/:id to photos#update with _id as parameter
DELETE /photos/:id to photos#delete with _id as parameter

It also creates the following helpers:

photosPath() returns /photos
newPhotoPath() returns /photos/new
editPhotoPath(42) returns /photos/42/edit
photoPath(42) returns /photos/42

Multiple resources can be defined at the same time:

router.resources(['photos', 'books']);

Single resource

Single resource can be defined:

router.resource('geocoder');

This statement creates the following routes:

GET /geocoder/new to geocoder#new
POST /geocoder to photos#create
GET /geocoder to geocoder#show
GET /geocoder/edit to _geocoder#edit
PATCH /geocoder to _geocoder#update
PUT /geocoder to _geocoder#update
DELETE /geocoder to _geocoder#delete

It also creates the following helpers:

geocoderPath() returns /geocoder
newGeocoderPath() returns /geocoder/new
editGeocoderPath(42) returns /geocoder/42/edit

Multiple single resources can be defined at the same time:

router.resource(['geocoder', 'profile']);

Nesting resources

Resources can be nested:

router.resources('magazines', function() {
  router.resources('ads');
});

In this case for example the express app can respond to GET /magazines/42/ads/7 path. It adds to req.params the following attributes:

magazineId (in this case: 42)
id (in this case: 7)

Namespace

Routes can be namespaced. In this case the controller should exists in a directory with the same name of the namespace.

router.namespace('admin', function() {
  router.resources('articles');
});

In this case the article resource's actions are mapped to the following paths:

GET /admin/articles
GET /admin/articles/new
POST /admin/articles
GET /admin/articles/:id
GET /admin/articles/:id/edit
PATCH /admin/articles/:id
PUT /admin/articles/:id
DELETE /admin/articles/:id

Scopes

Routes can be also scoped. In this case the controller should exists in a directory with the same name of the scope.

router.scope('admin', function() {
  router.resources('articles');
});

The difference with the namespace is that the routes paths don't have a prefix, but the controller lives inside a directory with the same name of the scope.

Fluent interface

Guidance router have a fluent interface, so it can be used in this way:

router
  .get('/geocoder', { to: 'geocoder#show' })
  .namespace('admin', function() {})
  .resources('books')
  .resource('geocoder')
  .scope('admin', function() {})
  .root('welcome#index')
  .post('/photos', { to: 'photos#create' })
;