Paloma

What's New?

Paloma (version 3) is almost a complete rewrite of the old version.

It is now simpler and it also gives more flexibility to the developers. Simplicity and flexibility are achieved by replacing the old callback thingy paradigm by a combination of Router and Controller components.

All the generator shits are also gone. So developers need not to follow specific folder structure or file name. And since there's no generated files or whatsoever, you can now code in vanilla javascript or coffescript! Yay!

Basically, Paloma now provides a Controller for your javascript!

Advantages

• Choose what specific javascript code to run per page.
• Easily make ruby variables available on your javascript files.

Quick Example

Paloma controller.

var UsersController = Paloma.controller('Users');

// Executes when Rails User#new is rendered.
UsersController.prototype.new = function(){
   alert('Hello Sexy User!' );
};

The Rails controller app/controllers/users_controller.rb:

def UsersController < ApplicationController
    def new
      @user = User.new
    end
end

That's it! Simply Sexy!

Minimum Requirements

• jQuery 1.7 or higher
• Rails 3.1 or higher

Install

Without bundler:

sudo gem install paloma

With bundler, add this to your Gemfile:

gem 'paloma'

Require paloma in your application.js:

//= require paloma

Router

Router is responsible for mapping Rails controller/action to its equivalent Paloma controller/action.

By default all Rails controller/action will be mapped with a Paloma controller/action with the same resource name (controller name without the Controller suffix).

Example:

• Response from UsersController#new will be mapped to Users Paloma controller and execute its new method.

Changing Controller

If you want to use a different Paloma Controller for a specific Rails controller, you can do the following:

// Instead of mapping Rails UsersController to Paloma Users
// it will be mapped to AdminUsers.
Paloma.router.resource('Users', {controller: 'AdminUsers'});

Redirecting

You can also redirect an action if you want it to be handled by a different method.

// Instead of executing Paloma's `Users#new` it will execute
// `Registrations#signUp`.
Paloma.router.redirect('Users#new', {to: 'Registrations#signUp');

Controller

Controller handles responses from Rails. A new controller instance is created by Paloma for every Rails controller/action that is executed.

Creating Controller

A Controller is created or accessed (if already existing) using:

Paloma.controller('ControllerName');

It returns the constructor of your controller. It is just a normal constructor so you can do your OOP stuff.

Creating actions

Add instance methods to you Controller constructor to handle actions.

var ArticlesController = Paloma.controller('ArticlesController');

ArticlesController.prototype.new = function(){
  // Handle new articles
};


ArticlesController.prototype.edit = function(){
  // Handle edit articles
};

Passing Parameters

You can also pass parameters to Paloma by calling js before render in your Rails controller. You can access the parameters on your Paloma controller using this.params object.

Example:

users_controller.rb

def destroy
    user = User.find params[:id]
    user.destroy
    
    js :id => user.id
end

Paloma controller.

var UsersController = Paloma.controller('Users');

UsersController.prototype.destroy = function(){
  alert('User ' + this.params['id'] + ' is deleted.');
};

Preventing Paloma

If you want to prevent Paloma from executing in a certain Rails controller action you can do it by passing false to js command.

def edit
  @user = User.find params[:id]
  js false
end

Execution Chains

Chains are created after a redirect action. The chain will continue to increase its length until a render action is detected.

Example:

def first_action
    redirect_to second_action_path
end

def second_action
    redirect_to third_action_path
end

def third_action
    render :template => 'third_action_view'
end

A request for first_action will lead to 2 redirects until it reaches the third_action and renders a result on the browser. When the third_action renders its response, Paloma will process all the request starting from first_action up to third_action.

Gotchas

• Paloma will not execute if the response is js, json, xml or any other format except html.

For example: render "something.js.erb"

Where to put code?

Again, Paloma is now flexible and doesn't force developers to follow specific folder structure. You have the freedom to create controllers and routes anywhere in your javascript code.

Personally, I prefer having a routes.js file to contain all the route declaration, and a javascript file for each controller.