GraphQL: add has_fragment to context

app/graphql/api/v2/context.rb

@@ -0,0 +1,30 @@
+class Api::V2::Context < GraphQL::Query::Context
+  def has_fragment?(name)
+    if self["has_fragment_#{name}"]
+      true
+    else
+      visitor = HasFragment.new(self.query.selected_operation, name)
+      visitor.visit
+      self["has_fragment_#{name}"] = visitor.found
+      self["has_fragment_#{name}"]
+    end
+  end
+
+  class HasFragment < GraphQL::Language::Visitor
+    def initialize(document, name)
+      super(document)
+      @name = name.to_s
+      @found = false
+    end
+
+    attr_reader :found
+
+    def on_inline_fragment(node, parent)
+      if node.type.name == @name
+        @found = true
+      end
+
+      super
+    end
+  end
+end

app/graphql/api/v2/schema.rb

@@ -6,6 +6,8 @@ class Api::V2::Schema < GraphQL::Schema
   query Types::QueryType
   mutation Types::MutationType
 
+  context_class Api::V2::Context
+
   def self.id_from_object(object, type_definition, ctx)
     object.to_typed_id
   end