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Friday, January 3, 2014

Rails Composer - A better way to build a Rails starter app


Rails Composer

An application template that creates a starter application for Rails 4.0 or Rails 3.2.
It’s the Rails generator on steroids. See the Rails Composer project page.
The Rails Composer application template is built from recipes provided by the rails_apps_composer gem. Need to customize the Rails Composer application template? Want to build your own application template? Use the rails_apps_composer gem.

 

What is the RailsApps Project?

 

The RailsApps project provides example applications that developers use as starter apps. Hundreds of developers use the apps, report problems as they arise, and propose solutions. Rails changes frequently; each application is known to work and serves as your personal “reference implementation.” Each application is accompanied by a tutorial so there is no mystery code. Support for the project comes from subscribers. Please accept our invitation to join the RailsApps project.

If You Are New to Rails

 

If you’re new to Rails, see What is Ruby on Rails?, the book Learn Ruby on Rails, and recommendations for a Rails tutorial.

Dependencies

 

Before running the Rails Composer tool, you need to install:
  • The Ruby language (version 2.0.0)
  • Rails 3.2 or Rails 4.0
Check that appropriate versions of Ruby and Rails are installed in your development environment:

$ ruby -v
$ rails -v

Be sure to read the article Installing Rails to make sure your development environment is set up properly.

Rails 3.2 or Rails 4.0

 

Depending on the version of Rails you use, different starter apps are available.

Creating a Starter App

 

To build a Rails application using the Rails Composer tool:
$ rails new myapp -m https://raw.github.com/RailsApps/rails-composer/master/composer.rb
Replace myapp with the name of your application.
The $ character indicates a shell prompt; don’t include it when you run the command.
You can use the -T flag to skip Test::Unit files or the -O flag to skip Active Record files:

$ rails new myapp -m https://raw.github.com/RailsApps/rails-composer/master/composer.rb -T -O

Skip Test::Unit if you plan to use RSpec for unit testing. Skip Active Record if you plan to use a NoSQL datastore with an ORM such as Mongoid.
See the “Troubleshooting” section below if you see errors. In general, you’ll avoid many problems if you create your application using RVM as described below.

Creating a Starter App Using RVM

 

I recommend using rvm, the Ruby Version Manager, to manage your Rails versions, as described in the Installing Rails article.
Here’s how to generate a new Rails application using the Rails Composer tool and RVM:

$ mkdir myapp
$ cd myapp
$ rvm use ruby-2.0.0@myapp --ruby-version --create
$ gem install rails
$ rails new . -m https://raw.github.com/RailsApps/rails-composer/master/composer.rb

You can add the -T flag to skip Test::Unit files or the -O flag to skip Active Record files. Skip Test::Unit if you plan to use RSpec for unit testing. Skip Active Record if you plan to use a NoSQL datastore with an ORM such as Mongoid.
Instead of installing Rails into the global gemset and running rails new, we’ll create a root directory for a new application, create a new gemset, install Rails, and then generate a starter application.
When we create the gemset, the option “—ruby-version” creates .ruby-version and .ruby-gemset files in the root directory. RVM recognizes these files in an application’s root directory and loads the required version of Ruby and the correct gemset whenever you enter the directory.
When we create the gemset, it will be empty (though it inherits use of all the gems in the global gemset). We immediately install Rails. The command gem install rails installs the most recent stable release of Rails.
Finally we run rails new .. We use the Unix “dot” convention to refer to the current directory. This assigns the name of the directory to the new application.
This approach is different from the way most beginners are taught to create a Rails application. Our approach makes it easy to create a project-specific gemset to avoid clashes between gem versions when using the Rails Composer tool.

Choose a RailsApps Starter Application

 

Use Rails Composer to generate any of the example applications from the RailsApps project. You’ll be able to choose your own project name when you generate the app. Generating the application gives you additional options.
To build the example application, Rails must be installed in your development environment.

Rails 3.2 or Rails 4.0

 

Choices of starter applications will differ depending on whether you are using Rails 4.0 or Rails 3.2.
Here’s an example:

$ rails new myapp -m https://raw.github.com/RailsApps/rails-composer/master/composer.rb

The $ character indicates a shell prompt; don’t include it when you run the command.
You can use the -T flag to skip Test::Unit files or the -O flag to skip Active Record files:

$ rails new myapp -m https://raw.github.com/RailsApps/rails-composer/master/composer.rb -T -O

This creates a new Rails app named myapp on your computer. You can use a different name if you wish.

Rails 4.0

 

With Rails 4.0, you’ll see a prompt:

question  Install an example application for Rails 4.0?
      1)  Build a RailsApps starter application
      2)  Build a contributed application
      3)  I want to build my own application

Enter “1” to select Build a RailsApps starter application. You’ll see a prompt:
 
question  Starter apps for Rails 4.0. More to come.
      1)  learn-rails
      2)  rails-bootstrap

Make your choice. The Rails Composer tool may give you other options (other applications may have been added since these notes were written).

Rails 3.2

 

With Rails 3.2, you’ll see a prompt:
 
question  Install an example application for Rails 3.2?
          1)  I want to build my own application
          2)  membership/subscription/saas
          3)  rails-prelaunch-signup
          4)  rails3-bootstrap-devise-cancan
          5)  rails3-devise-rspec-cucumber
          6)  rails3-mongoid-devise
          7)  rails3-mongoid-omniauth
          8)  rails3-subdomains

None of these Rails 3.2 example applications are available for Rails 4.0.

Options

 

The application generator template will ask you for additional preferences:
 
 question  Web server for development?
       1)  WEBrick (default)
       2)  Thin
       3)  Unicorn
       4)  Puma
 question  Web server for production?
       1)  Same as development
       2)  Thin
       3)  Unicorn
       4)  Puma
 question  Template engine?
       1)  ERB
       2)  Haml
       3)  Slim
 question  Continuous testing?
       1)  None
       2)  Guard
 question  Front-end framework?
       1)  None
       2)  Zurb Foundation 5.0
       3)  Zurb Foundation 4.0
       4)  Twitter Bootstrap 3.0
       5)  Twitter Bootstrap 2.3
       6)  Simple CSS
   extras  Set a robots.txt file to ban spiders? (y/n)
   extras  Create a GitHub repository? (y/n)
   extras  Use or create a project-specific rvm gemset? (y/n) 
 

Web Servers

 

We recommend Thin in development for speed and less noise in the log files.
If you plan to deploy to Heroku, select Thin as your production webserver. Unicorn is recommended by Heroku but configuration is more complex.

Template Engine

 

The example application uses the default “ERB” Rails template engine. Optionally, you can use another template engine, such as Haml or Slim. See instructions for Haml and Rails.

Continuous Testing

 

You won’t need “continuous testing” if you are a beginner. Select “none.”

Front-end Framework


If you choose a front-end framework, you’ll get an application layout file, plus navigation and flash messages, styled with a default theme.

Other Choices

 

Set a robots.txt file to ban spiders if you want to keep your new site out of Google search results.
If you choose to create a GitHub repository, the generator will prompt you for a GitHub username and password.
It is a good idea to use RVM, the Ruby Version Manager, and create a project-specific rvm gemset (not available on Windows). See Installing Rails.
h2. Build Your Own Application
If you choose “I want to build my own application,” you will get a wide set of choices.
These options are for experienced developers. Expect to spend time debugging your starter application as not all options are tested or fully supported.
Here’s an example of what you’ll see using Rails 4.0:

 
question  Install an example application for Rails 4.0?
      1)  Build a RailsApps starter application
      2)  Build a contributed application
      3)  I want to build my own application

question  Web server for development?
      1)  WEBrick (default)
      2)  Thin
      3)  Unicorn
      4)  Puma

question  Web server for production?
      1)  Same as development
      2)  Thin
      3)  Unicorn
      4)  Puma

question  Database used in development?
      1)  SQLite
      2)  PostgreSQL
      3)  MySQL
      4)  MongoDB

question  Template engine?
      1)  ERB
      2)  Haml
      3)  Slim (experimental)

question  Unit testing?
      1)  Test::Unit
      2)  RSpec
      3)  MiniTest

question  Integration testing?
      1)  None
      2)  RSpec with Capybara
      3)  Cucumber with Capybara
      4)  Turnip with Capybara
      5)  MiniTest with Capybara

question  Continuous testing?
      1)  None
      2)  Guard

question  Fixture replacement?
      1)  None
      2)  Factory Girl
      3)  Machinist
      4)  Fabrication

question  Front-end framework?
      1)  None
      2)  Zurb Foundation 4.0
      3)  Twitter Bootstrap 3.0
      4)  Twitter Bootstrap 2.3
      5)  Simple CSS

question  Add support for sending email?
      1)  None
      2)  Gmail
      3)  SMTP
      4)  SendGrid
      5)  Mandrill

question  Authentication?
      1)  None
      2)  Devise
      3)  OmniAuth

question  Devise modules?
      1)  Devise with default modules
      2)  Devise with Confirmable module
      3)  Devise with Confirmable and Invitable modules

question  Authorization?
      1)  None
      2)  CanCan with Rolify

question  Use a form builder gem?
      1)  None
      2)  SimpleForm

question  Install a starter app?
      1)  None
      2)  Home Page
      3)  Home Page, User Accounts
      4)  Home Page, User Accounts, Admin Dashboard

extras  Add 'therubyracer' JavaScript runtime (for Linux users without node.js)? (y/n)
extras  Set a robots.txt file to ban spiders? (y/n)
extras  Create a GitHub repository? (y/n)
extras  Use application.yml file for environment variables? (y/n)
extras  Reduce assets logger noise during development? (y/n)
extras  Improve error reporting with 'better_errors' during development? (y/n)
extras  Use or create a project-specific rvm gemset? (y/n)
 

Run the Application

 

Switch to the application directory to examine and test what you’ve built.
 
$ cd myapp 
 

Quick Test

 

For a “smoke test” to see if everything runs, display a list of Rake tasks.
 
$ rake -T

There’s no need to run bundle exec rake instead of rake when you are using rvm (see rvm and bundler integration).

Start the Web Server

 

If you’ve chosen WEBrick or Thin for your web server, can run the app by entering the command:

$ rails server

To see your application in action, open a browser window and navigate to http://localhost:3000/.
For the Unicorn web server:

$ unicorn

See the app at http://localhost:8080/.
For the Puma web server:

$ rails server puma

See the app at http://localhost:3000/.

Login

 

If you’ve created a version of the application that sets up a default user, log in with:
  • email: user@example.com
  • password: changeme
You should delete or change any pre-configured logins before you deploy your application.

Testing

 

Some versions of the starter application will contain a suite of RSpec unit tests or Cucumber scenarios and step definitions.
After installing the application, run rake -T to check that rake tasks for RSpec and Cucumber are available.
Run rake spec to run all RSpec tests.
Run rake cucumber (or more simply, cucumber) to run all Cucumber scenarios.
Please send the author a message, create an issue, or submit a pull request if you want to contribute improved RSpec or Cucumber files.

Deployment

 

For easy deployment, use a “platform as a service” provider such as:
For deployment on Heroku, see the article:

 

Troubleshooting

 

Problems? Please check both issues for the Rails Composer tool and the issues for the rails_apps_composer gem.
You should review the article Installing Rails to make sure you’ve updated all the components that are required to run Rails successfully.

Problems with “Could not be loaded… You have already activated…”

If you get an error like this:

 
Your bundle is complete! Use `bundle show [gemname]` to see where a bundled gem is installed.
    composer  Running 'after bundler' callbacks.
The template [...] could not be loaded.
Error: You have already activated ..., but your Gemfile requires ....
Using bundle exec may solve this.
 

It’s due to conflicting gem versions. See the article Rails Error: “You have already activated (…)”.

Problems with “Certificate Verify Failed”

 

Are you getting an error “OpenSSL certificate verify failed” when you try to generate a new Rails app from an application template? See suggestions to resolve the error Certificate Verify Failed.

Problems with “Segmentation Fault”

If you get a “segfault” when you try rails new, try removing and reinstalling rvm.

Application Template Default

 

The rails new command creates a new Rails application. If you want to use the Rails Composer application template for every Rails application you build, you can set options for the rails new command in a .railsrc file in your home directory. Here’s how to set up a .railsrc file to use the template when you create a new Rails application:
 
# ~/.railsrc
-m https://raw.github.com/RailsApps/rails-composer/master/composer.rb
 

Documentation and Support

 

The Rails Composer application template is assembled from recipes supplied by the rails_apps_composer gem. See the rails_apps_composer project to understand how the Rails Composer application works.

Customizing the Template

 

If you wish to change the template to generate an app with your own customized options, you can copy and edit the template file. However, it is better to use the rails_apps_composer gem to create a new application template. You’ll find newer versions of the recipes that make up the application template. You may find issues have been identified and (perhaps) fixed. And it will be easier to maintain your application template if you work from the rails_apps_composer gem.

Writing Recipes

 

To understand the code in these templates, take a look at Thor::Actions. Your recipes can use any methods provided by Thor::Actions or Rails::Generators::Actions. A big thanks to Yehuda Katz for creating Thor.

About Rails Application Templates

 

There is an unfinished Rails Guide on Rails Application Templates.
Also see:
Cooking Up A Custom Rails 3 Template (11 Oct 2010) by Andrea Singh
Rails Application Templates (16 Sept 2010) by Collin Schaafsma
Application templates in Rails 3 (18 Sept 2009) by Ben Scofield
Railscasts: App Templates in Rails 2.3 (9 Feb 2009) by Ryan Bates
Rails templates (4 Dec 2008) by Pratik Naik

Similar Projects

 

There are many similar projects: