Update Or Create

update_or_create.rb

# UpdateOrCreate makes it simple to to perform updating or creating models
# without a lot of boilerplate.
#
# It can be used in several forms. In its simplest form, it can be used with a
# single OrderedHash.
#
#     User.update_or_create(username: 'Admin', admin: true)
#
# The first key/value pair from the provided hash is used to look up any existing record.
# In this case, it will look for a user with the username 'Admin'
# If one is found, it is updated with the entire set of provided attributes.
# If none is found, a new one is created with the entire set of provided attributes.
#
# If you need more granular control of what record is looked up, or if you have imperfect
# control over the order of the provided Hash, you can provide the find_by options
# explicitly and then provide the remaining options used to update or create the instance.
#
#     # User 1 is going to be the Admin
#     User.update_or_create({ id: 1 }, { username: 'Admin', admin: true })
#
# Finally, if you need to provide more sophisticated handling of the instance and attributes
# used to update it you can provide a block that will be evaluated in the context of the found
# instance if one is found. The block will be passed the attributes you want to update the
# instance with. The block can then modify and return the hash of attributes you want to use to
# update the model. This is useful if you want to create models with a certain attribute but
# want to avoid re-setting in specific circumstances.
#
#     File.open('spec/support/data/default_avatar.png') do |f|
#       User.update_or_create(username: 'Admin', admin: true, avatar: f) do |attrs|
#         if avatar.try(:url)
#           attrs.except(:avatar)
#         else
#           attrs
#         end
#       end
#     end


module UpdateOrCreate
  def update_or_create find_by, updated_attributes = nil, &block
    update_or_create_with_methods find_by, updated_attributes, block, :update_attributes, :create
  end

  def update_or_create! find_by, updated_attributes = nil, &block
    update_or_create_with_methods find_by, updated_attributes, block, :update_attributes!, :create!
  end

  private
  def update_or_create_with_methods find_by, updated_attributes, block, update_method, create_method
    # If only a single hash of attributes was provided, extract find_by from it.
    unless updated_attributes
      # Promote find_by to updated_attributes
      # Create find_by from first entry of updated_attributes
      updated_attributes = find_by
      find_by = Hash[*updated_attributes.first]
    end

    instance = where(find_by).first

    if instance
      if block
        updated_attributes = block.bind(instance).call updated_attributes.dup
      end
      instance.send update_method, updated_attributes
    else
      instance = send create_method, updated_attributes.except(:id)
    end

    instance
  end
end

ActiveRecord::Relation.send :include, UpdateOrCreate
ActiveRecord::Base.send :extend, UpdateOrCreate