GraphQL::ResultCache

This gem is to cache the json result, instead of resolved object.

Installation

Add this line to your application's Gemfile:

gem 'graphql-result_cache'

And then execute:

$ bundle

Or install it yourself as:

$ gem install graphql-result_cache

Usage

1. Use GraphQL::ResultCache as a plugin in your schema. Only for implementations using graphql < 1.10.0.

class MySchema < GraphQL::Schema
  mutation Types::MutationType
  query Types::QueryType

  use GraphQL::ResultCache
end

2. Add the custom field class to accept result_cache metadata.

module Types
  class BaseObject < GraphQL::Schema::Object
    field_class GraphQL::ResultCache::Field
  end
end

3. Config the fields which need to be cached.

There are two approaches available to config the caching for the field. Using currently supported GraphQL gem Field Extension interface or Field Instrument interface which is no longer supported as of graphql 1.10.0.

Field Extension:

field :theme, Types::ThemeType, null: false, extensions: [GraphQL::ResultCache::FieldExtension]

Field Instrument:

Only to be used for implementations where graphql < 1.10.0.

field :theme, Types::ThemeType, null: false, result_cache: true

4. Wrap query result with GraphQL::ResultCache::Result.

class GraphqlController < ApplicationController
  def execute
    # ...
    result = if params[:_json]
               multiple_execute(params[:_json], context: context)
             else
               execute_query(context: context)
             end
    render json: GraphQL::ResultCache::Result.new(result)
  end
end

Result Cache Customization

Cache condition

The if condition can be either a Symbol or a Proc.

Field Extension

field :theme, Types::ThemeType, null: false, do
  extension GraphQL::ResultCache::FieldExtension, if: :published?
end

Field Instrument

field :theme, Types::ThemeType, null: false, result_cache: { if: :published? }

Customized cache key

By default, GraphQL::ResultCache will generate a cache key combining the field path, arguments and object. But you can customize the object clause by specify the key option.

Field Extension

field :theme, Types::ThemeType, null: false, do
  extension GraphQL::ResultCache::FieldExtension, key: :theme_cache_key
end

Field Instrument

field :theme, Types::ThemeType, null: false, result_cache: { key: :theme_cache_key }

The key can be either a Symbol or a Proc.

Callback after cached result applied

An after_process callback can be provided, eg. when some dynamic values need to be amended after cached result applied.

Field Extension

field :theme, Types::ThemeType, null: false, do
  extension GraphQL::ResultCache::FieldExtension, after_process: :amend_dynamic_attributes
end

Field Instrument

field :theme, Types::ThemeType, null: false, result_cache: { after_process: :amend_dynamic_attributes }

def amend_dynamic_attributes(theme_node)
  theme_node.merge! used_count: object.theme.used_count
end

Global Configuration

GraphQL::ResultCache can be configured in initializer.

# config/initializers/graphql/result_cache.rb

GraphQL::ResultCache.configure do |config|
  config.namespace   = "GraphQL:Result"                         # Cache key namespace
  config.expires_in  = 1.hour                                   # Expire time for the cache, default to 1.hour
  config.client_hash = -> { Rails.cache.read(:deploy_version) } # GraphQL client package hash key, used in cache key generation, default to nil
  config.except = ->(ctx) { !ctx[:result_cacheable] }           # Exception rule, skip the cache while evaluated as true, default to nil
  config.cache       = Rails.cache                              # The cache object, default to Rails.cache in Rails
  config.logger      = Rails.logger                             # The Logger, default to Rails.logger in Rails
end

When using with introspection, you need to assign custom introspection to avoid getting the nullable type for a non-null type.

class MySchema < GraphQL::Schema
  introspection ::GraphQL::ResultCache::Introspection
end

Development

After checking out the repo, run bin/setup to install dependencies. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/saharaying/graphql-result_cache. 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 GraphQL::ResultCache project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.