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Ruby on Rails

Note: These instructions are primarily intended for individual user accounts. If you are using a group account, you may wish to consider apphosting instead.

Ruby on Rails is a popular web framework for Ruby applications.

Creating a New Application

To create a new Rails application, use the rails command-line interface. For example, to create an application called foo in your home directory, run the command:

user@tsunami:~$ rails new foo

This may take some time.

Hosting Your Application

OCF allows hosting of Rails applications via FastCGI. This requires you to install the fcgi gem and create a FastCGI wrapper script.

Install fcgi gem

  1. Make sure the line gem 'fcgi' appears somewhere in your project's Gemfile (located at the root of the project).

  2. Run bundle install --path bundle from the root of your project to install bundled gems. This will also ensure that the fcgi gem is installed. You'll want to specify --path bundle so that bundler installs your gems to a local directory to your app and not system-wide. You'll also likely want to add the new bundle directory to your .gitignore if you are using git for version control.

Create FastCGI wrapper script

To host your application, create a file called dispatch.fcgi in your web root (~/public_html/) based on the following template:

#!/usr/bin/ruby
require 'etc'

APP_PATH = Etc.getpwuid.dir + '/foo'
ENV['GEM_HOME'] = APP_PATH + '/bundle/ruby/2.3.0/gems'
ENV['GEM_PATH'] = APP_PATH + '/bundle/ruby/2.3.0'

require_relative APP_PATH + '/config/environment'

class Rack::PathInfoRewriter
  def initialize(app)
    @app = app
  end

  def call(env)
    env.delete('SCRIPT_NAME')
    parts = env['REQUEST_URI'].split('?')
    env['PATH_INFO'] = parts[0]
    env['QUERY_STRING'] = parts[1].to_s
    @app.call(env)
  end
end

app, options = Rack::Builder.parse_file(APP_PATH + '/config.ru')
wrappedApp = Rack::Builder.new do
  use Rack::ShowExceptions
  use Rack::PathInfoRewriter
  run app
end

Rack::Handler::FastCGI.run wrappedApp

Be sure to adjust the path to your application near the top of the file (the APP_PATH variable)

Once you've added the dispatch.fcgi file, mark it as executable:

user@tsunami:~/public_html$ chmod +x dispatch.fcgi

Rewrite requests to the FastCGI wrapper

Create a file called .htaccess in your web root (or a subdirectory) containing the following lines:

RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ /~user/rails/dispatch.fcgi [QSA,L]

Be sure to change user and rails to your username and whatever directory name you made in public_html, respectively. (or remove rails if not inside a separate directory)

Rewriting asset and route paths

One issue you may run into is an error like No route matches [GET] "/~user". To fix an issue like this, the best method is to edit config/routes.rb in your application and add a scope block around all your routes matching the path you are using. For instance, if your site is at https://www.ocf.berkeley.edu/~user then convert your routes from something like this:

MyApp::Application.routes.draw do
  resources :users

  [...]
end

to something like this:

MyApp::Application.routes.draw do
  scope "~user" do
    resources :users

    [...]
  end
end

This will make your application able to route all your existing routes correctly. If your site is at something like https://www.ocf.berkeley.edu/~user/rails then use ~user/rails in the scope block instead. However, assets (images, stylesheets, javascript) may still be broken. To fix these, add a line like this into your config/application.rb (or under the correct environment in config/environments/(development,production).rb if you want to be more specific). Note that this has to be inside the class Application block:

Rails.application.config.assets.prefix = "/~user/asset"

Make sure to replace user in this example (and in your config/routes.rb) with your username, and add the path you are using for your application if applicable between ~user and ~asset.

Debugging

If you see an error page when trying to load your app, you may find the webserver's logs useful. You can access them in the following locations:

  • error log: /opt/httpd/error.log (most useful)
  • suexec log: /opt/httpd/suexec.log (only useful in rare cases)

Once your app has started running, changes you make to the Ruby code or templates won't take effect for a few hours. To apply changes immediately, you can touch the dispatch.fcgi file with the command:

user@tsunami:~/public_html$ touch dispatch.fcgi