Lets Get on Rails Venkat Subramaniam svenkat@cs.uh.edu 1 Whats - - PDF document

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Venkat Subramaniam – svenkat@cs.uh.edu

Let’s Get on Rails

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Venkat Subramaniam – svenkat@cs.uh.edu

What’s Rails?

• Web Development Frameworks
• Build on Ruby (so called Ruby on Rails)
• Agile
• Lightweight
• Heavily relies on Convention over

configuration

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Venkat Subramaniam – svenkat@cs.uh.edu

Built On Some Key Principles

• Rails follows some good principles

– MVC – DRY – Convention over configuration – “Unit Testing” – actually more than unit testing, though they call it that – Created bottom up – from real project, not designed by a committee

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Venkat Subramaniam – svenkat@cs.uh.edu

Convention Over Configuration

• No heavy XML based configuration
• As long as you follow convention, you

need to do less work

– A bit of a problem for newbies – You love it once you get used to it

• You name files in a certain way, put them

in specific places, …

• You can deviate from conventions if you

like, but the configuration is also using ruby, so fairly easy

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Venkat Subramaniam – svenkat@cs.uh.edu

Rails and MVC

• Rails follows MVC
• It actually does not simply promote MVC,

it follows you home, sits with you, and makes sure you follow it

• Controller receives request
• You access model to manipulate data
• It transfers control to a view for display

Browser

Controller

Model View

Business rules + data R O U T I N G

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Venkat Subramaniam – svenkat@cs.uh.edu

MVC in Rails

• Convention over configuration

– URL maps to an action on controller

• Controller performs logic
• Rails copies fields of controller to view
• View generates response to be rendered
• View: Action View
• Controller: Action Controller
• Model: Active Records

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Venkat Subramaniam – svenkat@cs.uh.edu

Let’s Build and Learn

• We will build an application and learn

about Rails, conventions, etc. using that example as a vehicle