class GraphQL::Schema::Directive::Feature

An example directive to show how you might interact with the runtime.

This directive might be used along with a server-side feature flag system like Flipper.

With that system, you could use this directive to exclude parts of a query if the current viewer doesn’t have certain flags enabled. (So, this flag would be for internal clients, like your iOS app, not third-party API clients.)

To use it, you have to implement .enabled?, for example:

Examples

Example: Implementing the Feature directive

# app/graphql/directives/feature.rb
class Directives::Feature < GraphQL::Schema::Directive::Feature
  def self.enabled?(flag_name, _obj, context)
    # Translate some GraphQL data for Ruby:
    flag_key = flag_name.underscore
    current_user = context[:viewer]
    # Check the feature flag however your app does it:
    MyFeatureFlags.enabled?(current_user, flag_key)
  end
end

Example: Flagging a part of the query

viewer {
  # This field only runs if `.enabled?("recommendationEngine", obj, context)`
  # returns true. Otherwise, it's treated as if it didn't exist.
  recommendations @feature(flag: "recommendationEngine") {
    name
    rating
  }
}

Public Class Methods

enabled?(String flag_name, GraphQL::Schema::Objct object, GraphQL::Query::Context context) → bool

Source

# File lib/graphql/schema/directive/feature.rb, line 77
def self.enabled?(flag_name, object, context)
  raise GraphQL::RequiredImplementationMissingError, "Implement `.enabled?(flag_name, object, context)` to return true or false for the feature flag (#{flag_name.inspect})"
end

Override this method in your app’s subclass of this directive.

Parameters

flag_name (String) — The client-provided string of a feature to check
object (GraphQL::Schema::Objct) — The currently-evaluated GraphQL object instance
context (GraphQL::Query::Context)

Returns

Boolean — If truthy, execution will continue

include? (object, arguments, context)

Source

# File lib/graphql/schema/directive/feature.rb, line 58
def self.include?(object, arguments, context)
  flag_name = arguments[:flag]
  self.enabled?(flag_name, object, context)
end

Implement the Directive API

resolve_field (...)

Source

# File lib/graphql/schema/directive/feature.rb, line 81
def self.resolve_field(...); end

resolve_fragment_spread (...)

Source

# File lib/graphql/schema/directive/feature.rb, line 82
def self.resolve_fragment_spread(...); end

resolve_inline_fragment (...)

Source

# File lib/graphql/schema/directive/feature.rb, line 83
def self.resolve_inline_fragment(...); end