A custom middleware for graphql-ruby

• Provide resolver-level caching for GraphQL APIs written in ruby
• Configurable to work with or without Rails
• API Documentation

At StackShare we've been rolling out graphql-ruby for several of our new features and found ourselves in need of a caching solution. We could have simply used Rails.cache in our resolvers, but this creates very verbose types or resolver classes. It also means that each and every resolver must define it's own expiration and key. GraphQL Cache solves that problem by integrating caching functionality into the graphql-ruby resolution process making caching transparent on most fields except for a metadata flag denoting the field as cached. More details on our motivation for creating this here.

Add this line to your application's Gemfile:

gem 'graphql-cache'

And then execute:

$ bundle

Or install it yourself as:

$ gem install graphql-cache

1. Use GraphQL Cache as a plugin in your schema.

class MySchema < GraphQL::Schema
  query Types::Query

  use GraphQL::Cache
end

2. Add the custom caching field class to your base object class. This adds the cache metadata key when defining fields.

module Types
  class Base < GraphQL::Schema::Object
    field_class GraphQL::Cache::Field
  end
end

GraphQL Cache can be configured in an initializer:

# config/initializers/graphql_cache.rb

GraphQL::Cache.configure do |config|
  config.namespace = 'GraphQL::Cache' # Cache key prefix for keys generated by graphql-cache
  config.cache     = Rails.cache      # The cache object to use for caching
  config.logger    = Rails.logger     # Logger to receive cache-related log messages
  config.expiry    = 5400             # 90 minutes (in seconds)
  config.force     = false            # Cache override, when true no caching takes place
end

Any object, list, or connection field can be cached by simply adding cache: true to the field definition:

field :calculated_field, Int, cache: true

By default all keys will have an expiration of GraphQL::Cache.expiry which defaults to 90 minutes. If you want to set a field-specific expiration time pass a hash to the cache parameter like this:

field :calculated_field, Int, cache: { expiry: 10800 } # expires key after 180 minutes

When passing a hash in the cache parameter the possible options are:

• expiry: expiration time for this field's key in seconds (default: 5400)
• force: for cache misses on this field (default: false)
• prefix: cache key prefix (appended after GraphQL::Cache.namespace)

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. 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.

Bug reports and pull requests are welcome on GitHub at https://github.com/stackshareio/graphql-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.

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

Everyone interacting in the graphql-cache project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.