WhereableScope

A Ruby gem that enhances ActiveRecord's where method to support calling scopes directly through the where clause.

Consider an Order model that originally had an address_id column:

# This worked when address_id was a column on orders
Order.where(address: address)

After migrating to a separate order_addresses join table, the associations become:

class Order < ActiveRecord::Base
  has_one :order_address
  has_one :address, through: :order_address
end

Now the old where(address: ...) syntax no longer works - potentially breaking many existing queries throughout your codebase.

With WhereableScope, you can preserve the original query interface by mapping a scope to the address parameter:

class Order < ActiveRecord::Base
  has_one :order_address
  has_one :address, through: :order_address

  scope :by_address, ->(address) { joins(:order_address).where(order_addresses: { address: address }) }

  whereable_scope :by_address, as: :address
end

# These continue to work after the migration!
Order.where(address: address)
Order.where.not(address: address)

Add this line to your application's Gemfile and bundle install:

gem 'whereable_scope'

Register a scope with whereable_scope:

whereable_scope :by_address, as: :address

This takes:

• The scope name (e.g., :by_address)
• An as: option to define the parameter name used in where (e.g., as: :address)

Once registered, you can use it in where:

# These are now equivalent:
Order.by_address(address)
Order.where(address: address)

# Combine with other conditions:
Order.where(address: address, total: 100)

rewhere(address: ...) and unscope(where: :address) will not be able to revert the merged scope. Since the scope is applied via merge, the resulting query conditions are not tracked under the where parameter name.

After checking out the repo:

# Install dependencies
bundle install

# Run tests
bundle exec rake

The gem is available as open source under the terms of the MIT License.