Rails EngineAn awesome tool to extend your rails application

Muntasim AhmedPlatform Architect @ Tasawr Interactive

https://github.com/railscashmuntasim@tasawr.com

Agenda

• Why Rails Engine• What is Rails Engine• How it works with Rails Core• Who are they• Where is your interest

Problems

• Large application without reusable component• Slow testing ( if any :) )• Larger app, messy

Solution• Find common functionalities• Extract them to module => Gems• Use railtie to tie with Rails App => Rails Engine

One Thing!

Rails (version>=3.1) is  just a “supercharged” engine

http://edgeguides.rubyonrails.org/engines.html

Rails Engine ?

• pre-packaged application • able to be run or mounted within another Rails

application• can have its own models, views, controllers,

generators and publicly served static files

Rails Engine ?

•   

Rails Engine has

Image source: Railscasts.com

Rails Engine has

Image source: Google

Rails Engine has

Image source: Google

Rails Engine has

Image source: Google

Rails engine walk-through

• Create an engine• Implement requirements  in app, lib etc.• Test• Mount to main app• Override where necessary • And done!

Rails engine walk-through

Create rails plugin new awesome_engine --mountable         

Then generate mvc stuffs, test

In App Gemfilegem "awesome_engine", path => "awesome_engine_path     

In App Routemount AwesomeEngine::Engine => "/awesome_engine_path", as => “awesome_engine"

Rails engine walk-through

Hit   localhost:3000/awesome_engine_path (mount point)

It will hit engine's root path         

Welcome to awesome engine home!

Rails engine walk-through

Routes:

Use engine routes from main app using engine_name.route_name

e.g.    awesome_name.root_path

Rails engine walk-through

Routes:

Use main app routes from engine using main_app.route_name 

e.g. main_app.root_path

Who are they

• Rails Admin• Devise• Blogit• Tolk• .....

References

• http://railscasts.com/episodes/277-mountable-engines• http://www.slideshare.net/AndyMaleh/rails-engine-patterns• http://www.slideshare.net/mirrec/rails-engine-rubyslava• http://edgeguides.rubyonrails.org/engines.html• http://edgeapi.rubyonrails.org/classes/Rails/Engine.html• http://pivotallabs.com/users/shagemann/blog/articles/1994-

migrating-rom-a-single-rails-app-to-a-suite-of-rails-engines

Image source:Google, Railscasts and Dulal Khan

Thanks for your attention :)

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Question(s)