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

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