CODEWITHSUNDEEP
ruby-on-railsrubyactiverecordrubygemsmetaprogramming
smallsense
smallsense

Reputation: 815

Ruby metaprogramming to generate ActiveRecord associations on a given model?

I'm extracting part of my app into a Gem, which involves creating some new ActiveRecord models. At the moment these models look something like this:

Class Wordcount < ActiveRecord::Base
  belongs_to :keyword
  belongs_to :article
end

Class Keyword < ActiveRecord::Base
  has_many :wordcounts
  has_many :articles, :through => :wordcounts
end

The gem will hook into any ActiveRecord model with String or Text fields, not just my defined Article model in the existing Rails app this code comes from.

What do I need to do in order to generate the relevant AR associations based on whichever model the gem's functionality is being applied to? I'm hoping to end up with:

has_my_gem_functionality :on => [:field1, :field2, ...]

And for the rest to be safely encapsulated within the gem.

I'm assuming I'll also have to metaprogram the Migrations as well. I think what I'm trying to do is relatively simple, it's just slightly too far out of my comfort zone.

Upvotes: 1

Views: 1086

Answers (1)

iblue
iblue

Reputation: 30404

Use the source, luke! :)

Just take a look at the source of some other gems that do similar things. For example:

Upvotes: 1

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