Using an application's name in Rails 3.1 application templates

Create more powerful rails app generators

When I want to try something new like a heroku addon, I generally like to try it out in a dummy app, to make sure it does what I expect and know how to configure it before I muck around in a working production app.

So to begin I make a new rails app, do some config stuff, create my local databases on postgresql (since I frequently deploy to heroku I use postgresql locally so my development and test environments are as close to production as I can get, for this reason I also use the thin server.) I almost always also install ActiveAdmin and track the AdminUser as an ActiveAdmin resource.

I realized that I tend to create these dummy apps quite frequently and got tired of repeating all the steps above. A rails app template seemed the logical choice. I had used simple templates in older versions of rails to do things like remove public/index.html and to use jquery.

In order to automate the database creation and config I needed the application name however I had some trouble figuring a variable that points to the application’s in my template files and the
Rails Application Templates guide provided a bunch of information but not the info I was looking for. The proposed solutions I found from web searches on the topic didn’t work. I found what I was looking for in the source docs for Rails::Generators::AppGenerator, namely the following variables

language: 'ruby'
  [app_const, app_const_base, app_name, app_secret, camelized]

file: basic_template_info.rb

language: 'ruby'
puts "----------"
%w(app_const app_const_base app_name app_secret camelized).each do |v|
  puts "#{v} => #{eval v}"
end
puts "----------"

language: 'shell-unix-generic'
  prompt$> rails new great_application -m basic_template_info.rb

language: 'shell-unix-generic'
    ...
  create  vendor/plugins
    create  vendor/plugins/.gitkeep
    apply  /Users/billy/Rails/utils/templates/basic.rb
  --------------------
  app_const => MyGreatApplication::Application
  app_const_base => MyGreatApplication
  app_name => my_great_application
  app_secret => 2c10...f5c211
  camelized => MyGreatApplication
  --------------------
           run  bundle install
  Fetching source index for http://rubygems.org/
  Using rake (0.9.2) 
  Using multi_json (1.0.3) 
  Using activesupport (3.1.0) 
  Using bcrypt-ruby (3.0.1) 
  ...

Hope this quickie helped you to write more powerful rails 3.1 application templates.

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