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Contents 1 Introduction . 3 2 Getting Started . 5 2.1 Installation . 5 2.2 Installation on Windows . 5 2.3 Install on OS X . 7 2.4 Install on Linux . 8 2.5 Concepts . 9 2.6 Don´t repeat yourself . 9 2.7 Model-View-Controller . 9 2.8 Convention over Configuration . 11 2.9 First Application . 11 2.10 First Application . 11 2.11 Running the Rails server . 17 3 Built-In Rails Tools . 19 3.1 Generators . 19 3.2 Generators . 19 3.3 Rake . 22 3.4 Database Tasks . 22 3.5 Test Tasks . 22 3.6 Cache Tasks . 22 4 ActiveRecord - The Model . 25 4.1 Naming . 25 4.2 Migrations . 26 4.3 Associations . 31 4.4 Callbacks . 36 4.5 Validations . 40 4.6 Attributes . 43 5 > #<Product: id . 45 5.1 Aggregations . 46 5.2 Calculations . 48 6 ActionView - The View . 53 6.1 Rendering and Redirecting . 53 6.2 Layout Files . 55 6.3 Forms . 57 6.4 Uploads . 62 6.5 Custom Helpers . 62 7 ActionController - The Controller . 65 7.1 Introduction . 65 7.2 Actions . 65 7.3 Parameters . 66 III Contents 7.4 Session . 66 7.5 Cookies . 67 8 Routing . 69 8.1 Understanding Routes and Routing . 69 8.2 See also . 73 9 ActiveSupport . 75 10 ActionMailer . 77 10.1 Model . 77 10.2 Mailer Views . 78 10.3 Sending HTML Mail . 78 10.4 Multipart Mail . 78 10.5 Attachments . 79 10.6 Configuration Options . 80 11 Examples . 81 11.1 Step By Step . 81 11.2 Find . 81 11.3 Rake . 82 11.4 Server . 83 11.5 Fixing Errors . 83 11.6 Shell Commands . 83 12 Other Resources . 85 12.1 Plugins . 85 12.2 Websites . 85 12.3 Books . 86 12.4 Development Tools . 86 12.5 Weblogs . 87 12.6 Mailing List . 87 12.7 Freenode ROR Channel . 87 13 Contributors . 89 List of Figures . 91 14 Licenses . 95 14.1 GNU GENERAL PUBLIC LICENSE . 95 14.2 GNU Free Documentation License . 96 14.3 GNU Lesser General Public License . 96 Note: the current version of this book can be found at http://en.wikibooks.org/wiki/ Ruby_on_Railshttp:// 1 1 Introduction Ruby on Rails, or often seen as RoR or just Rails, is an web application framework written in the programming language Ruby. Rails was created to be a project management tool for " 37signals1". Quickly, it became one of the most popular frameworks on the web and its ideas and philosophies has inspired many frameworks in different languages. 1.0.1 Features • Rails supports agile software development2 • Rails has a short and very intuitive language • Single blocks of code are intended to be short and clear • Rails is very flexible • Rails comes with a testing framework • The framework follows the principles of DRY3 (Don't repeat yourself) • Rails has some conventions: these allow quick development and consistent code • Rails uses the MVC-Architecture4 (Model-View-Controller) • Rails comes with an integrated server for local testing • Applications with Rails are RESTful5 1 http://www.37signals.com 2 http://en.wikipedia.org/wiki/Agile_development 3 http://en.wikipedia.org/wiki/Don%27t_repeat_yourself 4 http://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller 5 http://en.wikipedia.org/wiki/Representational_State_Transfer 3 2 Getting Started 2.1 Installation 2.2 Installation on Windows To start, you will need the following components: • Ruby • RubyGems • Rails • a driver for your database 2.2.1 Ruby Install Ruby as a regular application. You might need administrator privileges to install it successfully. Check the Ruby site.