ActiveRecord::PGArray

This gem defines methods in your models for ActiveRecord 4.0+ attributes that use Postgresql's arrays.

I wrote this gem because I realized that working with Postgresql arrays was not as straight-forward as I had hoped.

Installation

Add this line to your application's Gemfile:

gem 'activerecord-pg_array'

Usage

Then in your classes that inherit from ActiveRecord include ActiveRecord::PGArray

Silly Example:

Given the following migration:

class CreateWolfTracker < ActiveRecord::Migration
  def change
    create_table :wolf_trackers do |t|
      t.string :name
      t.integer :wolf_ids, array: true, default: []
      t.string :pack_names, array: true, default: []
    end

    add_index :wolf_trackers, :wolf_ids, using: 'gin'
  end
end

And class:

class WolfTracker < ActiveRecord::Base
  include ActiveRecord::PGArray
  # if doing anything with the pack_names and passing Wold instances, Wolf#name
  # will be the attribute used when serializing to pack_names
  # Using config_array_serializer is optional.
  config_array_serializer pack_names: {:Wolf => :name}
end

The following methods are automatically defined for "wolf_ids":

tracker.add_wolf(wolfy)            # ActiveRecord object wolfy's id is appended to wolf_ids
tracker.add_wolf!(son_of_wolfy)    # wolf_ids appended with atomic update
tracker.add_wolves([wolfia, 4])    # add multiple to wolf_ids. Note: irregular plural method name and mixed input
tracker.add_wolves!([wolfia, 4])    # add multiple to wolf_ids and persists. Note: irregular plural method name and mixed input. Can take multiple arguments or an array.
tracker.add_wolves!(wolfia, son_of_wolfy) # add multiple and persist. Can take multiple arguments or an array
tracker.remove_wolf(wolfia)        # wolf_ids is modified but not saved
tracker.remove_wolf!(3)            # wolf_ids atomic removal
tracker.remove_wolves(3, wolfia)   # wolf_ids has two items removed but is not persisted. Can take multiple arguments or an array
tracker.remove_wolves!([3, wolfia])  # wolf_ids has two items removed and is persisted. Can take multiple arguments or an array
tracker.wolves                     # looks up wolf objects with ids wolf_ids

The same is true for pack_names:

tracker.add_pack_name('Stark')
tracker.add_pack_name!('Karstark')
tracker.add_pack_names(['Greyjoy', 'Bolton'])
tracker.remove_pack_name('Greyjoy')
tracker.remove_pack_name!('Bolton')
# Does not define a finder method based on pack_names.
# If you define a custom array_serializer with config_array_serializer you can use this the same like:
tracker.add_pack_names([wolf])
tracker.remove_pack_name!(wolf)

Dynamically created method rules

If an ActiveRecord attribute ends with "_ids", that suffix will be removed from the method name.
If the attribute is an array of integers ending with "_ids", then if an ActiveRecord object is passed to it, the id of that object will used.
Method names will use the singular or plural form of the attribute name when defining the method.

Roadmap

rdoc documentation

Contributing

Fork it
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create new Pull Request

activerecord-pg_array

Development