GraphqlLazyLoad
Lazy executor for activerecord associations and graphql gem.
Installation
GraphqlLazyLoad requires ActiveRecord >= 4.1.16 and Graphql >= 1.3.0. To use add this line to your application’s Gemfile:
ruby
gem 'graphql_lazy_load', '~> 0.3.0'
Then run bundle install.
Or install it yourself as:
$ gem install graphql_lazy_load
Usage
To use, first add the executor (GraphqlLazyLoad::ActiveRecordRelation and/or GraphqlLazyLoad::Custom) to graphqls schema:
```ruby
class MySchema < GraphQL::Schema
mutation(Types::MutationType)
query(Types::QueryType)
lazy_resolve(GraphqlLazyLoad::ActiveRecordRelation, :result) lazy_resolve(GraphqlLazyLoad::Custom, :result) end ```
Now you can start using it!
The easiest thing to do is to extend the object helper method in the Types::BaseObject (or where you want to use the methods):
ruby
module Types
class BaseObject < GraphQL::Schema::Object
extend GraphqlLazyLoad::ObjectHelper
end
end
ActiveRecordRelation Syntax
ruby
field :field_name, Types::AssociationType, null: false
lazy_load_association(:field_name)
If the association does not match the field name you can pass it lazy_load_association(:field_name, association: :association_name)
Custom Syntax
ruby
field :field_name, Types::AssociationType, null: false
lazy_load_custom(:field_name, :id) do |field_name_ids|
# return hash of field_name_id => association_name, ...
AssociationName.where(id: ids).reduce({}) do |acc, value|
acc[value.id] = value
acc
end
end
Examples
If you have two models Team which can have many Players. To lazy load players from teams do the following:
### ActiveRecordRelation
ruby
module Types
class TeamType < Types::BaseObject
# extend GraphqlLazyLoad::ObjectHelper # uncomment if not extended in Types::BaseObject
...
field :players, [Types::PlayerType], null: false
lazy_load_association(:players)
end
end
And to lazy load teams from players do the following:
ruby
module Types
class PlayerType < Types::BaseObject
...
field :team, Types::TeamType, null: false
lazy_load_association(:team)
end
end
### Custom
ruby
module Types
class TeamType < Types::BaseObject
...
field :players, [Types::PlayerType], null: false
lazy_load_custom(:players, :id) do |team_ids|
# return a hash with key team_id => [player,...]
Player.where(team_id: team_ids).group_by(&:team_id)
end
end
end
And to lazy load teams from players do the following:
ruby
module Types
class PlayerType < Types::BaseObject
...
field :team, Types::TeamType, null: false
lazy_load_custom(:field_name, :team_id) do |team_ids|
# return a hash with key team_id => team
Team.where(id: team_ids).each_with_object({}) do |team, acc|
acc[team.id] = team
end
end
end
end
Scoping
The great thing is you can pass params. So for the example above if you want to allow sorting (or query, paging, etc) on player do the following.
### ActiveRecordRelation
ruby
module Types
class PlayerType < Types::BaseObject
...
field :players, [Types::PlayerType], null: false do
argument :order, String, required: false
end
lazy_load_association(:players) do |order: nil|
scope = Player.all
scope = scope.sort(order.underscore) if order
scope
end
end
end
Custom
ruby
module Types
class PlayerType < Types::BaseObject
...
field :players, [Types::PlayerType], null: false do
argument :order, String, required: false
end
lazy_load_custom(:players, :id) do |team_ids, order: nil|
# return a hash with key team_id => [player,...]
query = Player.where(team_id: team_ids)
query = query.order(params[:order].underscore) if params[:order]
query.group_by(&:team_id)
end
end
end
To test this out try the example app at graph_test
Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/jonathongardner/graphql_lazy_load. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.
License
The gem is available as open source under the terms of the MIT License.
Code of Conduct
Everyone interacting in the GraphqlLazyLoad project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.