Table of Contents

• Introduction
• Ruby on Rails Directory Structure

Introduction

By the end of this book, you’ll be able to:

• know where to put your html, css, & js within the structure of a ruby on rails app
• how rails routes requests to controllers
• using views, layouts, and partials in controllers
• what the asset pipeline is and how to use it
• how controllers and views in rails work together to render a response in the browser
• how data is added to views and how to link to the data in your html

Ruby on Rails Directory Structure

Since the intended audience of this book are front end developers, we’re going to skip over a lot of the rails structure and cover only the directories and files that the front end dev needs to know about to get his/her content to the browser. If you’d like to read about all of the rails structure, see the rails getting started guide (http://guides.rubyonrails.org/getting_started.html#creating-a-new-rails-project).

The core application code (the MVC business) in a rails project is in the app directory:

• app/controllers is where the controllers live in a rails application. Again, the controller is responsible for processing incoming requests by getting necessary data and rendering a view to the user. This is the entry point to behavior in the application.
• app/models is where the models live in a rails application. The models represent an instance of a data type in your application, perform functions unique to that data type, and persist and fetch data from a database.
• app/views is where the HTML views of the application live. They’re traditionally written in ERB, but you can use whatever template engine you like (even none at all if you’re so brash). You’ll be putting your HTML in this directory and a controller that’s responding to a request will incorporate your view with the render function (see how controllers and views work together).
• app/assets okay, here’s where you’ll be doing most of your work. Your javascript files go into the directory named app/assets/javascripts/ and your css files go into the app/assets/stylesheets/ directory. Also note that just like with views, you can append a filename to your file that tells rails which preprocessor to run your code through before serving it as plan javascript or css. For more on that, see “asset pipeline”.

Within app/assets:

• app/assets/images Put all of your images here.
• app/assets/javascripts Your javascript code will be preprocessed, concatenated into files that you specify (the default is application.js), and minified for production by Rail’s asset compilation engine, Sprockets.
• app/assets/stylesheets is where the default application.css file lives that Sprockets will compile for you.

• public is where static pages (like a 404 page), compiled assets (your plain and minified javascript and css after any preprocessors), and other static assets (like images) are placed to be served without any application logic by Apache (http://httpd.apache.org/) (Rails uses Apache as its web server – remember that bit about rails being a “full stack” framework?). The advantage of this is when a request is made for one of these assets, no rails code at all needs to be executed and the web server can simply serve the file back. This lowers stress on the rails application by not having to handle as many requests and makes for faster responses.

Within public:

• public/assets is where Sprockets will place compiled assets (CSS/JS) to be served by the web server. They will not be visible here in development because the Rails server will use Sprockets to compile them on the fly during each request. In production, they are compiled into this directory.

Lastly, like any good front-end developer, you’ll want to lean on the experience of your peers by using some javascript and css libraries. Simply place those libraries in either vendor/assets/javascripts or vendor/assets/stylesheets and you’ll be able to require them in your code in app/assets. Rails (technically Sprockets) will bundle everything up into one javascript or css file, put it in public and you’ll be good to go.