itkrt2y · September 3, 2024 11:45 · Mar 10, 2022 · Mar 10, 2022 · Mar 10, 2022 · Mar 10, 2022
diff --git a/example.rb b/example.rb
@@ -0,0 +1,40 @@
+class User < ApplicationRecord
+  has_many :posts
+end
+class Post < ApplicationRecord
+  belongs_to :user
+  has_many :comments
+end
+class Comment < ApplicationRecord
+  belongs_to :post
+end
+
+module Types
+  class UserType < Types::BaseObject
+    field :id, ID, null: false
+    field :posts, [Types::PostType], null: false
+    def posts
+      dataloader.with(Sources::Association, :posts, ::Post.preload(:comments)).load(object)
+    end
+  end
+
+  class PostType < Types::BaseObject
+    field :id, ID, null: false
+    field :user, Types::UserType, null: false
+    def user
+      dataloader.with(Sources::Association, :user).load(object)
+    end
+    field :comments, [Types::CommentType], null: false
+    def comments
+      dataloader.with(Sources::Association, :comments).load(object)
+    end
+  end
+
+  class CommentType < Types::BaseObject
+    field :id, ID, null: false
+    field :post, Types::PostType, null: false
+    def post
+      dataloader.with(Sources::Association, :post).load(object)
+    end
+  end
+end
diff --git a/association.rb b/association.rb
@@ -1,8 +1,6 @@
 # official docs: https://graphql-ruby.org/dataloader/sources.html
 
 # app/graphql/sources/association.rb
-# frozen_string_literal: true
-
 class Sources::Association < ::GraphQL::Dataloader::Source
   def initialize(association_name, scope = nil)
     @association_name = association_name

diff --git a/association.rb b/association.rb
@@ -1,15 +1,12 @@
 # official docs: https://graphql-ruby.org/dataloader/sources.html
 
 # app/graphql/sources/association.rb
+# frozen_string_literal: true
+
 class Sources::Association < ::GraphQL::Dataloader::Source
-  def initialize(association_name, preload_model = nil, preload_scope = nil)
+  def initialize(association_name, scope = nil)
     @association_name = association_name
-
-    # `dataloader.with(Sources::Association, :foo, Model.preload(scope))` のように
-    # 最初からpreloadしたクラスを渡すと処理がbatchにならないため、別々に渡した上で内部で結合する
-    @scope = if preload_model && preload_scope
-      preload_model.preload(preload_scope)
-    end
+    @scope = scope
   end
 
   def fetch(records)
@@ -18,4 +15,9 @@ def fetch(records)
     # ::ActiveRecord::Associations::Preloader.new(records: records, associations: @association_name, scope: @scope).call
     records.map { |record| record.public_send(@association_name) }
   end
+
+  # https://github.com/rmosolgo/graphql-ruby/blob/821ca53048fa5803fb90596719b4fedd65029ecb/lib/graphql/dataloader/source.rb#L113-L129
+  def self.batch_key_for(*batch_args, **batch_kwargs)
+    [*batch_args.map { |arg| arg.try(:to_sql) || arg }, **batch_kwargs]
+  end
 end
diff --git a/association.rb b/association.rb
@@ -15,7 +15,7 @@ def initialize(association_name, preload_model = nil, preload_scope = nil)
   def fetch(records)
     ::ActiveRecord::Associations::Preloader.new.preload(records, @association_name, @scope)
     # Rails7
-    # ::ActiveRecord::Associations::Preloader.new.preload(records: records, associations: @association_name, scope: @scope).call
+    # ::ActiveRecord::Associations::Preloader.new(records: records, associations: @association_name, scope: @scope).call
     records.map { |record| record.public_send(@association_name) }
   end
 end
diff --git a/association.rb b/association.rb
@@ -15,7 +15,7 @@ def initialize(association_name, preload_model = nil, preload_scope = nil)
   def fetch(records)
     ::ActiveRecord::Associations::Preloader.new.preload(records, @association_name, @scope)
     # Rails7
-    # ::ActiveRecord::Associations::Preloader.new.preload(records: records, associations: @association_name, scope: @scope)
+    # ::ActiveRecord::Associations::Preloader.new.preload(records: records, associations: @association_name, scope: @scope).call
     records.map { |record| record.public_send(@association_name) }
   end
 end
diff --git a/association.rb b/association.rb
@@ -14,6 +14,8 @@ def initialize(association_name, preload_model = nil, preload_scope = nil)
 
   def fetch(records)
     ::ActiveRecord::Associations::Preloader.new.preload(records, @association_name, @scope)
+    # Rails7
+    # ::ActiveRecord::Associations::Preloader.new.preload(records: records, associations: @association_name, scope: @scope)
     records.map { |record| record.public_send(@association_name) }
   end
 end
diff --git a/association.rb b/association.rb
@@ -0,0 +1,19 @@
+# official docs: https://graphql-ruby.org/dataloader/sources.html
+
+# app/graphql/sources/association.rb
+class Sources::Association < ::GraphQL::Dataloader::Source
+  def initialize(association_name, preload_model = nil, preload_scope = nil)
+    @association_name = association_name
+
+    # `dataloader.with(Sources::Association, :foo, Model.preload(scope))` のように
+    # 最初からpreloadしたクラスを渡すと処理がbatchにならないため、別々に渡した上で内部で結合する
+    @scope = if preload_model && preload_scope
+      preload_model.preload(preload_scope)
+    end
+  end
+
+  def fetch(records)
+    ::ActiveRecord::Associations::Preloader.new.preload(records, @association_name, @scope)
+    records.map { |record| record.public_send(@association_name) }
+  end
+end