The Even-Darker Art of Rails Engines

Location: Pavilion 9 - 10 Level:
Average rating: ***..
(3.38, 69 ratings)

When I started talking about the idea of ‘Rails Engines’ a few years ago, everyone thought I was crazy. Some people said it was stupid, or just plain evil. Despite that, the ability to write simple yet powerful plugins is baked into the core of Rails 2.3.

But heed the words of Uncle Ben: “With great power, comes great responsibility!”

In this session, we’ll discuss how to best take advantage of ‘engines’, in which situations engine plugins are appropriate and those where they aren’t, and how to avoid some of the common issues that can arrive when developing with engine-style plugins.

When we’re done, you’ll be in the best position to take advantage of this newly-sanctified functionality in your own projects.

Photo of James Adam

James Adam

Free Range

James has been developing using Ruby since 2001. He is one of the primary instigators of the London Ruby User Group, and has presented to Ruby and Rails developers in Vancouver, London, Santa Clara and Portland.

Most recently, he organised a new kind of conference – Ruby Manor – demonstrating the potential and passion of the UK Ruby community.

He’s been an active member of the Rails community since its inception, and is the developer behind the Engines plugin. He’s also author of the Rails Plugins book.

He pretends not to have a blog at

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Picture of Lori Olson
Lori Olson
05/05/2009 4:06pm PDT

Great talk. I let myself be talked out of engines by the (formerly) bad press. Couldn’t be happier to see this change, because my app is an engine, and the sooner we make that change, the better.

Picture of Emmanuel Sambo
Emmanuel Sambo
05/05/2009 5:45am PDT

Well prepared. Good and funny slides. Very useful tips and calls for action.

Picture of James Adam
James Adam
05/05/2009 5:29am PDT

I hope that Yehuda & Carl’s talk will cover the 3.0 scene, and I would’ve loved to cover some of the bases of using engines, but I think the most interesting and relevant aspects at the moment are the conceptual issues with sharing chunks of an app.

I’m sad that limited time didn’t let me take questions, but we had a ton to cover; I hope I did it justice. And of course, I’m always happy to discuss other stuff with anyone – grab me if you see me wandering around :)

Michael Gaffney
05/05/2009 4:38am PDT

He got a lot of “Here’s what hurts” across.

Russ McBride
05/05/2009 4:36am PDT

Nice talk by a sharp guy. It would have been good to set the stage much more: how engines differ from plugins and generators; the motivation for engines instead of plugins and generators; what’s happening with 3.0 and engines. Then maybe a bit on what engines are out there and use one. Bonus: a sketch of how to write your own engine.

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