GraphQL field extensions

boilerplate.rb

require "bundler/inline"

gemfile do
  source "https://rubygems.org"

  gem "graphql"
end

class BaseObject < GraphQL::Schema::Object
end

class QueryType < BaseObject
  field :cached_val, String, null: false

  def cached_val
    "I'm cached at #{Time.now}"
  end
end

class GraphqlSchema < GraphQL::Schema
  query QueryType
end

query = <<-gql
  query {
    cachedVal
  }
gql

puts GraphqlSchema.execute(query).dig("data", "cachedVal")
sleep 3
puts GraphqlSchema.execute(query).dig("data", "cachedVal")

extension.rb

require "bundler/inline"

gemfile do
  source "https://rubygems.org"

  gem "graphql"
end

class BaseObject < GraphQL::Schema::Object
end

class CacheExtension < GraphQL::Schema::FieldExtension
  def resolve(object:, arguments:, **rest)
    key = cache_key(object, arguments)
    store[key] ||= yield(object, arguments)
  end

  private

  def store
    Thread.current[:field_cache] ||= {}
  end

  def cache_key(object, arguments)
    "#{object.class.name}-#{@field}-#{arguments.hash}"
  end
end

class QueryType < BaseObject
  field :cached_val, String, null: false, extensions: [CacheExtension]

  def cached_val
    "I'm cached at #{Time.now}"
  end
end

class GraphqlSchema < GraphQL::Schema
  query QueryType
end

query = <<-gql
  query {
    cachedVal
  }
gql

puts GraphqlSchema.execute(query).dig("data", "cachedVal")
sleep 3
puts GraphqlSchema.execute(query).dig("data", "cachedVal")

kwarg.rb

require "bundler/inline"

gemfile do
  source "https://rubygems.org"

  gem "graphql"
end

class BaseObject < GraphQL::Schema::Object
  field_class.prepend(Module.new do
    def initialize(*args, **kwargs, &block)
      if kwargs.delete(:cached)
        kwargs[:extensions] ||= [] << CacheExtension
      end

      super
    end
  end)
end

class CacheExtension < GraphQL::Schema::FieldExtension
  def resolve(object:, arguments:, **rest)
    key = cache_key(object, arguments)
    store[key] ||= yield(object, arguments)
  end

  private

  def store
    Thread.current[:field_cache] ||= {}
  end

  def cache_key(object, arguments)
    "#{object.class.name}-#{@field}-#{arguments.hash}"
  end
end

class QueryType < BaseObject
  field :cached_val, String, null: false, cached: true

  def cached_val
    "I'm cached at #{Time.now}"
  end
end

class GraphqlSchema < GraphQL::Schema
  query QueryType
end

query = <<-gql
  query {
    cachedVal
  }
gql

puts GraphqlSchema.execute(query).dig("data", "cachedVal")
sleep 3
puts GraphqlSchema.execute(query).dig("data", "cachedVal")