Alternatives for Ruby on Rails and/or its components

Question

I'm curious about alternatives to the components of RoR or RoR itself.

Some research brought up the ORM alternatives to ActiveRecord here on SO.

So remaining is the question about alternatives for...

1. ... the controllers (ActiveController)
2. ... the views (ActiveView)
3. ... RoR itself
4. ... any other component I'm missing here :D

Really, I'm very happy with all of them, but I'm asking out of pure curiosity.

Answer 1

In place of ActiveRecord, there are a few to choose from. The biggest competitor (and my favorite) seems to be DataMapper, then there's Sequel, Mongoid, MongoMapper. There are plenty of others too, but these are relatively big players.

In place of ActionView (not Active... Action... confusing, I know), I haven't come across anything. I've seen plenty of additions to it, but no complete replacements. I guess that means people are mostly happy with ActionView. Now, there are other template-engines available though. The big player here is HAML. Using HAML doesn't mean you're not using ActionView though. You're still using ActionView, just with a different template pre-processor.

Alternatives to RoR itself. Again, there are a few. The big players are Sinatra, Merb (which started in the early Rails days by some people who disagreed with a thing or two in Rails, and then Rails learnt a thing or two and took some bits and pieces back again... confusing!). There's also Ramaze, but I don't know much about it.

The thing is, Rails is more or less unrivaled in what it does. If you get your hands on a web app written in Ruby, it's probably going to either be a Rails app or a Sinatra app. Sinatra meets a different need to Rails. Rails wants to provide you with a whole array of tools to get things done quickly, while Sinatra's main goal is to be lightweight and keep out of your way. Rails is huge, while Sinatra basically boils down a glorified route map/dispatcher (I mean this in a good way), leaving you to build your web app however you see fit. Sinatra makes it easy to package a small web admin tool inside a gem, for example. You probably wouldn't want to include a Rails app inside a gem. That would be pretty overkill.

In terms of "other components", the big thing (though it's not a Rails thing) that comes to mind is Test::Unit. While Rails just ships with Test::Unit, and doesn't constrain you from using something else, it's worth mentioning that there are other testing frameworks available. RSpec is the other big player here, and there's also ZenTest. You may also look at Shoulda, which is an add-on, more than an alternative.