From 8fec40d5b873dc62e8bc29b8ebfe71a003b09dab Mon Sep 17 00:00:00 2001
From: Nikita Bulai <bulaj.nikita@gmail.com>
Date: Wed, 29 Jan 2020 11:38:13 +0300
Subject: [PATCH] Improve code style

---
 .rubocop.yml                                  |  1 +
 .rubocop_todo.yml                             | 40 +++++++++++++++++++
 .../doorkeeper/application_controller.rb      |  4 +-
 .../application_metal_controller.rb           |  4 +-
 lib/doorkeeper.rb                             |  2 +-
 lib/doorkeeper/grape/helpers.rb               |  2 +-
 lib/doorkeeper/helpers/controller.rb          | 10 ++---
 lib/doorkeeper/models/access_grant_mixin.rb   |  4 +-
 lib/doorkeeper/models/access_token_mixin.rb   | 12 +++---
 lib/doorkeeper/models/application_mixin.rb    |  4 +-
 lib/doorkeeper/models/concerns/ownership.rb   |  2 +-
 lib/doorkeeper/models/concerns/reusable.rb    |  2 +-
 lib/doorkeeper/oauth/authorization/code.rb    |  2 +-
 lib/doorkeeper/oauth/authorization/token.rb   |  4 +-
 lib/doorkeeper/oauth/base_request.rb          |  4 +-
 .../oauth/client_credentials/creator.rb       |  6 +--
 .../oauth/client_credentials/validation.rb    |  2 +-
 lib/doorkeeper/oauth/error_response.rb        |  6 +--
 lib/doorkeeper/oauth/helpers/scope_checker.rb |  2 +-
 lib/doorkeeper/oauth/helpers/unique_token.rb  | 13 +++---
 .../oauth/password_access_token_request.rb    |  2 +-
 lib/doorkeeper/oauth/pre_authorization.rb     |  2 +-
 lib/doorkeeper/oauth/token.rb                 |  2 +-
 lib/doorkeeper/oauth/token_introspection.rb   |  6 +--
 lib/doorkeeper/orm/active_record.rb           |  4 +-
 .../orm/active_record/mixins/access_grant.rb  |  5 ++-
 .../orm/active_record/mixins/access_token.rb  |  5 ++-
 .../orm/active_record/mixins/application.rb   |  2 +-
 .../active_record/redirect_uri_validator.rb   |  6 +--
 lib/doorkeeper/rails/helpers.rb               |  6 +--
 lib/doorkeeper/rails/routes.rb                |  4 +-
 lib/doorkeeper/rake/db.rake                   |  4 +-
 lib/doorkeeper/request.rb                     |  2 +-
 lib/doorkeeper/request/authorization_code.rb  |  2 +-
 lib/doorkeeper/request/client_credentials.rb  |  2 +-
 lib/doorkeeper/request/password.rb            |  2 +-
 lib/doorkeeper/request/refresh_token.rb       |  2 +-
 lib/doorkeeper/server.rb                      |  2 +-
 lib/doorkeeper/stale_records_cleaner.rb       |  2 +-
 .../application_metal_controller_spec.rb      |  2 +-
 .../applications_controller_spec.rb           |  5 ++-
 .../authorizations_controller_spec.rb         | 30 +++++++-------
 spec/lib/doorkeeper_spec.rb                   |  2 +-
 43 files changed, 135 insertions(+), 92 deletions(-)
 create mode 100644 .rubocop_todo.yml

diff --git a/.rubocop.yml b/.rubocop.yml
index 2145b4cfe..2f4b917cd 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,3 +1,4 @@
+inherit_from: .rubocop_todo.yml
 require: rubocop-performance
 AllCops:
   TargetRubyVersion: 2.4
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
new file mode 100644
index 000000000..26f113cdf
--- /dev/null
+++ b/.rubocop_todo.yml
@@ -0,0 +1,40 @@
+# This configuration was generated by
+# `rubocop --auto-gen-config`
+# on 2020-01-29 11:31:56 +0300 using RuboCop version 0.78.0.
+# The point is for the user to remove these configuration records
+# one by one as the offenses are removed from the code base.
+# Note that changes in the inspected code, or installation of new
+# versions of RuboCop, may require this file to be generated again.
+
+# Offense count: 1
+# Configuration parameters: CountComments, ExcludedMethods.
+# ExcludedMethods: refine
+Metrics/BlockLength:
+  Max: 58
+
+# Offense count: 2
+# Configuration parameters: CountComments.
+Metrics/ClassLength:
+  Max: 214
+
+# Offense count: 4
+# Configuration parameters: CountComments.
+Metrics/ModuleLength:
+  Max: 470
+
+# Offense count: 1
+# Configuration parameters: EnforcedStyleForLeadingUnderscores.
+# SupportedStylesForLeadingUnderscores: disallowed, required, optional
+Naming/MemoizedInstanceVariableName:
+  Exclude:
+    - 'lib/doorkeeper/oauth/authorization/code.rb'
+
+# Offense count: 5
+# Configuration parameters: MinBodyLength.
+Style/GuardClause:
+  Exclude:
+    - 'lib/doorkeeper/config.rb'
+    - 'lib/doorkeeper/helpers/controller.rb'
+    - 'lib/doorkeeper/oauth/client/credentials.rb'
+    - 'lib/doorkeeper/oauth/helpers/scope_checker.rb'
+    - 'lib/doorkeeper/oauth/token.rb'
diff --git a/app/controllers/doorkeeper/application_controller.rb b/app/controllers/doorkeeper/application_controller.rb
index 80be8a165..beb1888ac 100644
--- a/app/controllers/doorkeeper/application_controller.rb
+++ b/app/controllers/doorkeeper/application_controller.rb
@@ -2,10 +2,10 @@
 
 module Doorkeeper
   class ApplicationController <
-    Doorkeeper.configuration.resolve_controller(:base)
+    Doorkeeper.config.resolve_controller(:base)
     include Helpers::Controller
 
-    unless Doorkeeper.configuration.api_only
+    unless Doorkeeper.config.api_only
       protect_from_forgery with: :exception
       helper "doorkeeper/dashboard"
     end
diff --git a/app/controllers/doorkeeper/application_metal_controller.rb b/app/controllers/doorkeeper/application_metal_controller.rb
index 3072cf696..caea55878 100644
--- a/app/controllers/doorkeeper/application_metal_controller.rb
+++ b/app/controllers/doorkeeper/application_metal_controller.rb
@@ -2,11 +2,11 @@
 
 module Doorkeeper
   class ApplicationMetalController <
-    Doorkeeper.configuration.resolve_controller(:base_metal)
+    Doorkeeper.config.resolve_controller(:base_metal)
     include Helpers::Controller
 
     before_action :enforce_content_type,
-                  if: -> { Doorkeeper.configuration.enforce_content_type }
+                  if: -> { Doorkeeper.config.enforce_content_type }
 
     ActiveSupport.run_load_hooks(:doorkeeper_metal_controller, self)
   end
diff --git a/lib/doorkeeper.rb b/lib/doorkeeper.rb
index edd5c863c..86550bffc 100644
--- a/lib/doorkeeper.rb
+++ b/lib/doorkeeper.rb
@@ -85,7 +85,7 @@
 # Main Doorkeeper namespace.
 #
 module Doorkeeper
-  def self.authenticate(request, methods = Doorkeeper.configuration.access_token_methods)
+  def self.authenticate(request, methods = Doorkeeper.config.access_token_methods)
     OAuth::Token.authenticate(request, *methods)
   end
 end
diff --git a/lib/doorkeeper/grape/helpers.rb b/lib/doorkeeper/grape/helpers.rb
index 6862fbdc4..6b6743e6f 100644
--- a/lib/doorkeeper/grape/helpers.rb
+++ b/lib/doorkeeper/grape/helpers.rb
@@ -39,7 +39,7 @@ def endpoint
       def doorkeeper_token
         @doorkeeper_token ||= OAuth::Token.authenticate(
           decorated_request,
-          *Doorkeeper.configuration.access_token_methods,
+          *Doorkeeper.config.access_token_methods,
         )
       end
 
diff --git a/lib/doorkeeper/helpers/controller.rb b/lib/doorkeeper/helpers/controller.rb
index 48f7a37d5..b4a3264d7 100644
--- a/lib/doorkeeper/helpers/controller.rb
+++ b/lib/doorkeeper/helpers/controller.rb
@@ -17,17 +17,17 @@ def authenticate_resource_owner!
       # :doc:
       def current_resource_owner
         @current_resource_owner ||= begin
-          instance_eval(&Doorkeeper.configuration.authenticate_resource_owner)
+          instance_eval(&Doorkeeper.config.authenticate_resource_owner)
         end
       end
 
       def resource_owner_from_credentials
-        instance_eval(&Doorkeeper.configuration.resource_owner_from_credentials)
+        instance_eval(&Doorkeeper.config.resource_owner_from_credentials)
       end
 
       # :doc:
       def authenticate_admin!
-        instance_eval(&Doorkeeper.configuration.authenticate_admin)
+        instance_eval(&Doorkeeper.config.authenticate_admin)
       end
 
       def server
@@ -40,7 +40,7 @@ def doorkeeper_token
       end
 
       def config_methods
-        @config_methods ||= Doorkeeper.configuration.access_token_methods
+        @config_methods ||= Doorkeeper.config.access_token_methods
       end
 
       def get_error_response_from_exception(exception)
@@ -67,7 +67,7 @@ def handle_token_exception(exception)
       def skip_authorization?
         !!instance_exec(
           [server.current_resource_owner, @pre_auth.client],
-          &Doorkeeper.configuration.skip_authorization
+          &Doorkeeper.config.skip_authorization
         )
       end
 
diff --git a/lib/doorkeeper/models/access_grant_mixin.rb b/lib/doorkeeper/models/access_grant_mixin.rb
index 31e9835de..6fba84104 100644
--- a/lib/doorkeeper/models/access_grant_mixin.rb
+++ b/lib/doorkeeper/models/access_grant_mixin.rb
@@ -103,14 +103,14 @@ def pkce_supported?
       # Determines the secret storing transformer
       # Unless configured otherwise, uses the plain secret strategy
       def secret_strategy
-        ::Doorkeeper.configuration.token_secret_strategy
+        ::Doorkeeper.config.token_secret_strategy
       end
 
       ##
       # Determine the fallback storing strategy
       # Unless configured, there will be no fallback
       def fallback_secret_strategy
-        ::Doorkeeper.configuration.token_secret_fallback_strategy
+        ::Doorkeeper.config.token_secret_fallback_strategy
       end
     end
   end
diff --git a/lib/doorkeeper/models/access_token_mixin.rb b/lib/doorkeeper/models/access_token_mixin.rb
index a1c7917a7..565dd21a3 100644
--- a/lib/doorkeeper/models/access_token_mixin.rb
+++ b/lib/doorkeeper/models/access_token_mixin.rb
@@ -158,7 +158,7 @@ def scopes_match?(token_scopes, param_scopes, app_scopes)
         (token_scopes.sort == param_scopes.sort) &&
           Doorkeeper::OAuth::Helpers::ScopeChecker.valid?(
             scope_str: param_scopes.to_s,
-            server_scopes: Doorkeeper.configuration.scopes,
+            server_scopes: Doorkeeper.config.scopes,
             app_scopes: app_scopes,
           )
       end
@@ -181,7 +181,7 @@ def scopes_match?(token_scopes, param_scopes, app_scopes)
       # @return [Doorkeeper::AccessToken] existing record or a new one
       #
       def find_or_create_for(application, resource_owner_id, scopes, expires_in, use_refresh_token)
-        if Doorkeeper.configuration.reuse_access_token
+        if Doorkeeper.config.reuse_access_token
           access_token = matching_token_for(application, resource_owner_id, scopes)
 
           return access_token if access_token&.reusable?
@@ -234,14 +234,14 @@ def last_authorized_token_for(application_id, resource_owner_id)
       # Determines the secret storing transformer
       # Unless configured otherwise, uses the plain secret strategy
       def secret_strategy
-        ::Doorkeeper.configuration.token_secret_strategy
+        ::Doorkeeper.config.token_secret_strategy
       end
 
       ##
       # Determine the fallback storing strategy
       # Unless configured, there will be no fallback
       def fallback_secret_strategy
-        ::Doorkeeper.configuration.token_secret_fallback_strategy
+        ::Doorkeeper.config.token_secret_fallback_strategy
       end
     end
 
@@ -350,7 +350,7 @@ def generate_refresh_token
     end
 
     # Generates and sets the token value with the
-    # configured Generator class (see Doorkeeper.configuration).
+    # configured Generator class (see Doorkeeper.config).
     #
     # @return [String] generated token value
     #
@@ -375,7 +375,7 @@ def generate_token
     end
 
     def token_generator
-      generator_name = Doorkeeper.configuration.access_token_generator
+      generator_name = Doorkeeper.config.access_token_generator
       generator = generator_name.constantize
 
       return generator if generator.respond_to?(:generate)
diff --git a/lib/doorkeeper/models/application_mixin.rb b/lib/doorkeeper/models/application_mixin.rb
index 95ce55b65..bcc36e350 100644
--- a/lib/doorkeeper/models/application_mixin.rb
+++ b/lib/doorkeeper/models/application_mixin.rb
@@ -47,14 +47,14 @@ def by_uid(uid)
       # Determines the secret storing transformer
       # Unless configured otherwise, uses the plain secret strategy
       def secret_strategy
-        ::Doorkeeper.configuration.application_secret_strategy
+        ::Doorkeeper.config.application_secret_strategy
       end
 
       ##
       # Determine the fallback storing strategy
       # Unless configured, there will be no fallback
       def fallback_secret_strategy
-        ::Doorkeeper.configuration.application_secret_fallback_strategy
+        ::Doorkeeper.config.application_secret_fallback_strategy
       end
     end
 
diff --git a/lib/doorkeeper/models/concerns/ownership.rb b/lib/doorkeeper/models/concerns/ownership.rb
index 714723645..634c023c6 100644
--- a/lib/doorkeeper/models/concerns/ownership.rb
+++ b/lib/doorkeeper/models/concerns/ownership.rb
@@ -11,7 +11,7 @@ module Ownership
       end
 
       def validate_owner?
-        Doorkeeper.configuration.confirm_application_owner?
+        Doorkeeper.config.confirm_application_owner?
       end
     end
   end
diff --git a/lib/doorkeeper/models/concerns/reusable.rb b/lib/doorkeeper/models/concerns/reusable.rb
index 4084ba67d..70b335741 100644
--- a/lib/doorkeeper/models/concerns/reusable.rb
+++ b/lib/doorkeeper/models/concerns/reusable.rb
@@ -11,7 +11,7 @@ def reusable?
         return false if expired?
         return true unless expires_in
 
-        threshold_limit = 100 - Doorkeeper.configuration.token_reuse_limit
+        threshold_limit = 100 - Doorkeeper.config.token_reuse_limit
         expires_in_seconds >= threshold_limit * expires_in / 100
       end
     end
diff --git a/lib/doorkeeper/oauth/authorization/code.rb b/lib/doorkeeper/oauth/authorization/code.rb
index 8ee48c872..38a46b09d 100644
--- a/lib/doorkeeper/oauth/authorization/code.rb
+++ b/lib/doorkeeper/oauth/authorization/code.rb
@@ -22,7 +22,7 @@ def oob_redirect
         private
 
         def authorization_code_expires_in
-          Doorkeeper.configuration.authorization_code_expires_in
+          Doorkeeper.config.authorization_code_expires_in
         end
 
         def access_grant_attributes
diff --git a/lib/doorkeeper/oauth/authorization/token.rb b/lib/doorkeeper/oauth/authorization/token.rb
index c18d797b4..6b8af3ae3 100644
--- a/lib/doorkeeper/oauth/authorization/token.rb
+++ b/lib/doorkeeper/oauth/authorization/token.rb
@@ -57,7 +57,7 @@ def issue_token
             pre_auth.scopes,
           )
 
-          @token = Doorkeeper.config.access_token_model.find_or_create_for(
+          @token = configuration.access_token_model.find_or_create_for(
             pre_auth.client,
             resource_owner.id,
             pre_auth.scopes,
@@ -77,7 +77,7 @@ def oob_redirect
         private
 
         def configuration
-          Doorkeeper.configuration
+          Doorkeeper.config
         end
 
         def controller
diff --git a/lib/doorkeeper/oauth/base_request.rb b/lib/doorkeeper/oauth/base_request.rb
index 176395b0f..23e2b0fd0 100644
--- a/lib/doorkeeper/oauth/base_request.rb
+++ b/lib/doorkeeper/oauth/base_request.rb
@@ -46,11 +46,11 @@ def find_or_create_access_token(client, resource_owner_id, scopes, server)
       end
 
       def before_successful_response
-        Doorkeeper.configuration.before_successful_strategy_response.call(self)
+        Doorkeeper.config.before_successful_strategy_response.call(self)
       end
 
       def after_successful_response
-        Doorkeeper.configuration.after_successful_strategy_response.call(self, @response)
+        Doorkeeper.config.after_successful_strategy_response.call(self, @response)
       end
 
       private
diff --git a/lib/doorkeeper/oauth/client_credentials/creator.rb b/lib/doorkeeper/oauth/client_credentials/creator.rb
index 1d5514a61..cdf3b63aa 100644
--- a/lib/doorkeeper/oauth/client_credentials/creator.rb
+++ b/lib/doorkeeper/oauth/client_credentials/creator.rb
@@ -7,9 +7,7 @@ class Creator
         def call(client, scopes, attributes = {})
           existing_token = existing_token_for(client, scopes)
 
-          if Doorkeeper.configuration.reuse_access_token && existing_token&.reusable?
-            return existing_token
-          end
+          return existing_token if Doorkeeper.config.reuse_access_token && existing_token&.reusable?
 
           existing_token&.revoke
 
@@ -22,7 +20,7 @@ def call(client, scopes, attributes = {})
         private
 
         def existing_token_for(client, scopes)
-          Doorkeeper.config.access_token_model.matching_token_for client, nil, scopes
+          Doorkeeper.config.access_token_model.matching_token_for(client, nil, scopes)
         end
       end
     end
diff --git a/lib/doorkeeper/oauth/client_credentials/validation.rb b/lib/doorkeeper/oauth/client_credentials/validation.rb
index f154d8fc9..2d99434fe 100644
--- a/lib/doorkeeper/oauth/client_credentials/validation.rb
+++ b/lib/doorkeeper/oauth/client_credentials/validation.rb
@@ -26,7 +26,7 @@ def validate_client
         end
 
         def validate_client_supports_grant_flow
-          Doorkeeper.configuration.allow_grant_flow_for_client?(
+          Doorkeeper.config.allow_grant_flow_for_client?(
             Doorkeeper::OAuth::CLIENT_CREDENTIALS,
             @client,
           )
diff --git a/lib/doorkeeper/oauth/error_response.rb b/lib/doorkeeper/oauth/error_response.rb
index c7ec4a77c..30d8104c3 100644
--- a/lib/doorkeeper/oauth/error_response.rb
+++ b/lib/doorkeeper/oauth/error_response.rb
@@ -46,9 +46,9 @@ def redirectable?
 
       def redirect_uri
         if @response_on_fragment
-          Authorization::URIBuilder.uri_with_fragment @redirect_uri, body
+          Authorization::URIBuilder.uri_with_fragment(@redirect_uri, body)
         else
-          Authorization::URIBuilder.uri_with_query @redirect_uri, body
+          Authorization::URIBuilder.uri_with_query(@redirect_uri, body)
         end
       end
 
@@ -70,7 +70,7 @@ def raise_exception!
       delegate :realm, to: :configuration
 
       def configuration
-        Doorkeeper.configuration
+        Doorkeeper.config
       end
 
       def exception_class
diff --git a/lib/doorkeeper/oauth/helpers/scope_checker.rb b/lib/doorkeeper/oauth/helpers/scope_checker.rb
index 213fdbce5..22ecec4be 100644
--- a/lib/doorkeeper/oauth/helpers/scope_checker.rb
+++ b/lib/doorkeeper/oauth/helpers/scope_checker.rb
@@ -13,7 +13,7 @@ def initialize(scope_str, server_scopes, app_scopes, grant_type)
             @valid_scopes = valid_scopes(server_scopes, app_scopes)
 
             if grant_type
-              @scopes_by_grant_type = Doorkeeper.configuration.scopes_by_grant_type[grant_type.to_sym]
+              @scopes_by_grant_type = Doorkeeper.config.scopes_by_grant_type[grant_type.to_sym]
             end
           end
 
diff --git a/lib/doorkeeper/oauth/helpers/unique_token.rb b/lib/doorkeeper/oauth/helpers/unique_token.rb
index 4fbf52750..6e40f0ccb 100644
--- a/lib/doorkeeper/oauth/helpers/unique_token.rb
+++ b/lib/doorkeeper/oauth/helpers/unique_token.rb
@@ -3,6 +3,9 @@
 module Doorkeeper
   module OAuth
     module Helpers
+      # Default Doorkeeper token generator. Follows OAuth RFC and
+      # could be customized using `default_generator_method` in
+      # configuration.
       module UniqueToken
         def self.generate(options = {})
           # Access Token value must be 1*VSCHAR or
@@ -11,15 +14,15 @@ def self.generate(options = {})
           # @see https://tools.ietf.org/html/rfc6749#appendix-A.12
           # @see https://tools.ietf.org/html/rfc6750#section-2.1
           #
-          generator_method = options.delete(:generator) || SecureRandom.method(self.generator_method)
-          token_size       = options.delete(:size)      || 32
-          generator_method.call(token_size)
+          generator = options.delete(:generator) || SecureRandom.method(default_generator_method)
+          token_size = options.delete(:size) || 32
+          generator.call(token_size)
         end
 
         # Generator method for default generator class (SecureRandom)
         #
-        def self.generator_method
-          Doorkeeper.configuration.default_generator_method
+        def self.default_generator_method
+          Doorkeeper.config.default_generator_method
         end
       end
     end
diff --git a/lib/doorkeeper/oauth/password_access_token_request.rb b/lib/doorkeeper/oauth/password_access_token_request.rb
index 530576e25..187909c03 100644
--- a/lib/doorkeeper/oauth/password_access_token_request.rb
+++ b/lib/doorkeeper/oauth/password_access_token_request.rb
@@ -50,7 +50,7 @@ def validate_client
       end
 
       def validate_client_supports_grant_flow
-        Doorkeeper.configuration.allow_grant_flow_for_client?(grant_type, client)
+        Doorkeeper.config.allow_grant_flow_for_client?(grant_type, client)
       end
     end
   end
diff --git a/lib/doorkeeper/oauth/pre_authorization.rb b/lib/doorkeeper/oauth/pre_authorization.rb
index f1e39fa4e..5d0e4599d 100644
--- a/lib/doorkeeper/oauth/pre_authorization.rb
+++ b/lib/doorkeeper/oauth/pre_authorization.rb
@@ -33,7 +33,7 @@ def authorizable?
       end
 
       def validate_client_supports_grant_flow
-        Doorkeeper.configuration.allow_grant_flow_for_client?(grant_type, client.application)
+        Doorkeeper.config.allow_grant_flow_for_client?(grant_type, client.application)
       end
 
       def scopes
diff --git a/lib/doorkeeper/oauth/token.rb b/lib/doorkeeper/oauth/token.rb
index 555eb2f3d..88d6e63d9 100644
--- a/lib/doorkeeper/oauth/token.rb
+++ b/lib/doorkeeper/oauth/token.rb
@@ -15,7 +15,7 @@ def from_request(request, *methods)
         def authenticate(request, *methods)
           if (token = from_request(request, *methods))
             access_token = Doorkeeper.config.access_token_model.by_token(token)
-            refresh_token_enabled = Doorkeeper.configuration.refresh_token_enabled?
+            refresh_token_enabled = Doorkeeper.config.refresh_token_enabled?
             if access_token.present? && refresh_token_enabled
               access_token.revoke_previous_refresh_token!
             end
diff --git a/lib/doorkeeper/oauth/token_introspection.rb b/lib/doorkeeper/oauth/token_introspection.rb
index afadbbb1a..fe385284e 100644
--- a/lib/doorkeeper/oauth/token_introspection.rb
+++ b/lib/doorkeeper/oauth/token_introspection.rb
@@ -174,9 +174,9 @@ def authorized_token_matches_introspected?
         authorized_token.token == @token&.token
       end
 
-      # config constraints for introspection in Doorkeeper.configuration.allow_token_introspection
+      # Config constraints for introspection in Doorkeeper.config.allow_token_introspection
       def token_introspection_allowed?(auth_client: nil, auth_token: nil)
-        allow_introspection = Doorkeeper.configuration.allow_token_introspection
+        allow_introspection = Doorkeeper.config.allow_token_introspection
         return allow_introspection unless allow_introspection.respond_to?(:call)
 
         allow_introspection.call(
@@ -193,7 +193,7 @@ def token_introspection_allowed?(auth_client: nil, auth_token: nil)
       # @see https://tools.ietf.org/html/rfc7662#section-2.2
       #
       def customize_response(response)
-        customized_response = Doorkeeper.configuration.custom_introspection_response.call(
+        customized_response = Doorkeeper.config.custom_introspection_response.call(
           token,
           server.context,
         )
diff --git a/lib/doorkeeper/orm/active_record.rb b/lib/doorkeeper/orm/active_record.rb
index fee5e977e..d250d0e51 100644
--- a/lib/doorkeeper/orm/active_record.rb
+++ b/lib/doorkeeper/orm/active_record.rb
@@ -20,9 +20,9 @@ def self.initialize_models!
           require "doorkeeper/orm/active_record/access_token"
           require "doorkeeper/orm/active_record/application"
 
-          if Doorkeeper.configuration.active_record_options[:establish_connection]
+          if Doorkeeper.config.active_record_options[:establish_connection]
             Doorkeeper::Orm::ActiveRecord.models.each do |model|
-              options = Doorkeeper.configuration.active_record_options[:establish_connection]
+              options = Doorkeeper.config.active_record_options[:establish_connection]
               model.establish_connection(options)
             end
           end
diff --git a/lib/doorkeeper/orm/active_record/mixins/access_grant.rb b/lib/doorkeeper/orm/active_record/mixins/access_grant.rb
index 3c03a9cce..e68eca4d1 100644
--- a/lib/doorkeeper/orm/active_record/mixins/access_grant.rb
+++ b/lib/doorkeeper/orm/active_record/mixins/access_grant.rb
@@ -9,8 +9,9 @@ module AccessGrant
 
       include ::Doorkeeper::AccessGrantMixin
 
-      belongs_to :application, class_name: Doorkeeper.configuration.application_class,
-                               optional: true, inverse_of: :access_grants
+      belongs_to :application, class_name: Doorkeeper.config.application_class,
+                               optional: true,
+                               inverse_of: :access_grants
 
       validates :resource_owner_id,
                 :application_id,
diff --git a/lib/doorkeeper/orm/active_record/mixins/access_token.rb b/lib/doorkeeper/orm/active_record/mixins/access_token.rb
index e11021632..6edd60f6b 100644
--- a/lib/doorkeeper/orm/active_record/mixins/access_token.rb
+++ b/lib/doorkeeper/orm/active_record/mixins/access_token.rb
@@ -9,8 +9,9 @@ module AccessToken
 
       include ::Doorkeeper::AccessTokenMixin
 
-      belongs_to :application, class_name: Doorkeeper.configuration.application_class,
-                               inverse_of: :access_tokens, optional: true
+      belongs_to :application, class_name: Doorkeeper.config.application_class,
+                               inverse_of: :access_tokens,
+                               optional: true
 
       validates :token, presence: true, uniqueness: { case_sensitive: true }
       validates :refresh_token, uniqueness: { case_sensitive: true }, if: :use_refresh_token?
diff --git a/lib/doorkeeper/orm/active_record/mixins/application.rb b/lib/doorkeeper/orm/active_record/mixins/application.rb
index e20aeafce..cf34134c2 100644
--- a/lib/doorkeeper/orm/active_record/mixins/application.rb
+++ b/lib/doorkeeper/orm/active_record/mixins/application.rb
@@ -87,7 +87,7 @@ def generate_secret
       def scopes_match_configured
         if scopes.present? && !Doorkeeper::OAuth::Helpers::ScopeChecker.valid?(
           scope_str: scopes.to_s,
-          server_scopes: Doorkeeper.configuration.scopes,
+          server_scopes: Doorkeeper.config.scopes,
         )
           errors.add(:scopes, :not_match_configured)
         end
diff --git a/lib/doorkeeper/orm/active_record/redirect_uri_validator.rb b/lib/doorkeeper/orm/active_record/redirect_uri_validator.rb
index 8fb8414d2..5c3683500 100644
--- a/lib/doorkeeper/orm/active_record/redirect_uri_validator.rb
+++ b/lib/doorkeeper/orm/active_record/redirect_uri_validator.rb
@@ -8,7 +8,7 @@ module Doorkeeper
   class RedirectUriValidator < ActiveModel::EachValidator
     def validate_each(record, attribute, value)
       if value.blank?
-        return if Doorkeeper.configuration.allow_blank_redirect_uri?(record)
+        return if Doorkeeper.config.allow_blank_redirect_uri?(record)
 
         record.errors.add(attribute, :blank)
       else
@@ -34,7 +34,7 @@ def oob_redirect_uri?(uri)
     end
 
     def forbidden_uri?(uri)
-      Doorkeeper.configuration.forbid_redirect_uri.call(uri)
+      Doorkeeper.config.forbid_redirect_uri.call(uri)
     end
 
     def unspecified_scheme?(uri)
@@ -48,7 +48,7 @@ def relative_uri?(uri)
     end
 
     def invalid_ssl_uri?(uri)
-      forces_ssl = Doorkeeper.configuration.force_ssl_in_redirect_uri
+      forces_ssl = Doorkeeper.config.force_ssl_in_redirect_uri
       non_https = uri.try(:scheme) == "http"
 
       if forces_ssl.respond_to?(:call)
diff --git a/lib/doorkeeper/rails/helpers.rb b/lib/doorkeeper/rails/helpers.rb
index 3ab7ef225..f1607c4b1 100644
--- a/lib/doorkeeper/rails/helpers.rb
+++ b/lib/doorkeeper/rails/helpers.rb
@@ -4,7 +4,7 @@ module Doorkeeper
   module Rails
     module Helpers
       def doorkeeper_authorize!(*scopes)
-        @_doorkeeper_scopes = scopes.presence || Doorkeeper.configuration.default_scopes
+        @_doorkeeper_scopes = scopes.presence || Doorkeeper.config.default_scopes
 
         doorkeeper_render_error unless valid_doorkeeper_token?
       end
@@ -21,7 +21,7 @@ def valid_doorkeeper_token?
 
       def doorkeeper_render_error
         error = doorkeeper_error
-        error.raise_exception! if Doorkeeper.configuration.raise_on_errors?
+        error.raise_exception! if Doorkeeper.config.raise_on_errors?
 
         headers.merge!(error.headers.reject { |k| k == "Content-Type" })
         doorkeeper_render_error_with(error)
@@ -72,7 +72,7 @@ def doorkeeper_invalid_token_response?
       def doorkeeper_token
         @doorkeeper_token ||= OAuth::Token.authenticate(
           request,
-          *Doorkeeper.configuration.access_token_methods,
+          *Doorkeeper.config.access_token_methods,
         )
       end
     end
diff --git a/lib/doorkeeper/rails/routes.rb b/lib/doorkeeper/rails/routes.rb
index b6a26920d..1b4d405ee 100644
--- a/lib/doorkeeper/rails/routes.rb
+++ b/lib/doorkeeper/rails/routes.rb
@@ -26,9 +26,7 @@ def initialize(routes, &block)
         @routes = routes
         @mapping = Mapper.new.map(&block)
 
-        if Doorkeeper.configuration.api_only
-          @mapping.skips.push(:applications, :authorized_applications)
-        end
+        @mapping.skips.push(:applications, :authorized_applications) if Doorkeeper.config.api_only
       end
 
       def generate_routes!(options)
diff --git a/lib/doorkeeper/rake/db.rake b/lib/doorkeeper/rake/db.rake
index 5cfac3996..044075476 100644
--- a/lib/doorkeeper/rake/db.rake
+++ b/lib/doorkeeper/rake/db.rake
@@ -21,7 +21,7 @@ namespace :doorkeeper do
       task expired_tokens: "doorkeeper:setup" do
         expirable_tokens = Doorkeeper.config.access_token_model.where(refresh_token: nil)
         cleaner = Doorkeeper::StaleRecordsCleaner.new(expirable_tokens)
-        cleaner.clean_expired(Doorkeeper.configuration.access_token_expires_in)
+        cleaner.clean_expired(Doorkeeper.config.access_token_expires_in)
       end
 
       desc "Removes stale access grants"
@@ -33,7 +33,7 @@ namespace :doorkeeper do
       desc "Removes expired (TTL passed) access grants"
       task expired_grants: "doorkeeper:setup" do
         cleaner = Doorkeeper::StaleRecordsCleaner.new(Doorkeeper::AccessGrant)
-        cleaner.clean_expired(Doorkeeper.configuration.authorization_code_expires_in)
+        cleaner.clean_expired(Doorkeeper.config.authorization_code_expires_in)
       end
     end
   end
diff --git a/lib/doorkeeper/request.rb b/lib/doorkeeper/request.rb
index a60830ff8..62606920c 100644
--- a/lib/doorkeeper/request.rb
+++ b/lib/doorkeeper/request.rb
@@ -24,7 +24,7 @@ def get_strategy(grant_type, available)
       private
 
       def token_grant_types
-        Doorkeeper.configuration.token_grant_types
+        Doorkeeper.config.token_grant_types
       end
 
       def build_strategy_class(grant_or_request_type)
diff --git a/lib/doorkeeper/request/authorization_code.rb b/lib/doorkeeper/request/authorization_code.rb
index 84f22719e..6f69a5650 100644
--- a/lib/doorkeeper/request/authorization_code.rb
+++ b/lib/doorkeeper/request/authorization_code.rb
@@ -7,7 +7,7 @@ class AuthorizationCode < Strategy
 
       def request
         @request ||= OAuth::AuthorizationCodeRequest.new(
-          Doorkeeper.configuration,
+          Doorkeeper.config,
           grant,
           client,
           parameters,
diff --git a/lib/doorkeeper/request/client_credentials.rb b/lib/doorkeeper/request/client_credentials.rb
index fe336a7b8..a86736d91 100644
--- a/lib/doorkeeper/request/client_credentials.rb
+++ b/lib/doorkeeper/request/client_credentials.rb
@@ -7,7 +7,7 @@ class ClientCredentials < Strategy
 
       def request
         @request ||= OAuth::ClientCredentialsRequest.new(
-          Doorkeeper.configuration,
+          Doorkeeper.config,
           client,
           parameters,
         )
diff --git a/lib/doorkeeper/request/password.rb b/lib/doorkeeper/request/password.rb
index 02eaccae8..16c2aba4c 100644
--- a/lib/doorkeeper/request/password.rb
+++ b/lib/doorkeeper/request/password.rb
@@ -7,7 +7,7 @@ class Password < Strategy
 
       def request
         @request ||= OAuth::PasswordAccessTokenRequest.new(
-          Doorkeeper.configuration,
+          Doorkeeper.config,
           client,
           resource_owner,
           parameters,
diff --git a/lib/doorkeeper/request/refresh_token.rb b/lib/doorkeeper/request/refresh_token.rb
index 35c6ab6d0..1c5edfc29 100644
--- a/lib/doorkeeper/request/refresh_token.rb
+++ b/lib/doorkeeper/request/refresh_token.rb
@@ -11,7 +11,7 @@ def refresh_token
 
       def request
         @request ||= OAuth::RefreshTokenRequest.new(
-          Doorkeeper.configuration,
+          Doorkeeper.config,
           refresh_token, credentials,
           parameters,
         )
diff --git a/lib/doorkeeper/server.rb b/lib/doorkeeper/server.rb
index 68eb1b2ee..5e0fd059e 100644
--- a/lib/doorkeeper/server.rb
+++ b/lib/doorkeeper/server.rb
@@ -37,7 +37,7 @@ def resource_owner
     end
 
     def credentials
-      methods = Doorkeeper.configuration.client_credentials_methods
+      methods = Doorkeeper.config.client_credentials_methods
       @credentials ||= OAuth::Client::Credentials.from_request(context.request, *methods)
     end
   end
diff --git a/lib/doorkeeper/stale_records_cleaner.rb b/lib/doorkeeper/stale_records_cleaner.rb
index c2d10c071..4214f4c2b 100644
--- a/lib/doorkeeper/stale_records_cleaner.rb
+++ b/lib/doorkeeper/stale_records_cleaner.rb
@@ -14,7 +14,7 @@ def self.for(base_scope)
     end
 
     def self.configured_orm
-      Doorkeeper.configuration.orm
+      Doorkeeper.config.orm
     end
 
     def self.new(base_scope)
diff --git a/spec/controllers/application_metal_controller_spec.rb b/spec/controllers/application_metal_controller_spec.rb
index a15b9a654..829173f04 100644
--- a/spec/controllers/application_metal_controller_spec.rb
+++ b/spec/controllers/application_metal_controller_spec.rb
@@ -21,7 +21,7 @@ def create
   end
 
   describe "enforce_content_type" do
-    before { allow(Doorkeeper.configuration).to receive(:enforce_content_type).and_return(flag) }
+    before { allow(Doorkeeper.config).to receive(:enforce_content_type).and_return(flag) }
 
     context "enabled" do
       let(:flag) { true }
diff --git a/spec/controllers/applications_controller_spec.rb b/spec/controllers/applications_controller_spec.rb
index 23d247f5b..90c72061b 100644
--- a/spec/controllers/applications_controller_spec.rb
+++ b/spec/controllers/applications_controller_spec.rb
@@ -117,7 +117,7 @@ module Doorkeeper
 
     context "when admin is not authenticated" do
       before do
-        allow(Doorkeeper.configuration).to receive(:authenticate_admin).and_return(proc do
+        allow(Doorkeeper.config).to receive(:authenticate_admin).and_return(proc do
           redirect_to main_app.root_url
         end)
       end
@@ -142,7 +142,8 @@ module Doorkeeper
     context "when admin is authenticated" do
       context "when application secrets are hashed" do
         before do
-          allow(Doorkeeper.configuration).to receive(:application_secret_strategy).and_return(Doorkeeper::SecretStoring::Sha256Hash)
+          allow(Doorkeeper.configuration)
+            .to receive(:application_secret_strategy).and_return(Doorkeeper::SecretStoring::Sha256Hash)
         end
 
         it "shows the application secret after creating a new application" do
diff --git a/spec/controllers/authorizations_controller_spec.rb b/spec/controllers/authorizations_controller_spec.rb
index ea03b9e65..d3939c232 100644
--- a/spec/controllers/authorizations_controller_spec.rb
+++ b/spec/controllers/authorizations_controller_spec.rb
@@ -27,8 +27,8 @@ def query_params
       end)
     end
 
-    allow(Doorkeeper.configuration).to receive(:grant_flows).and_return(["implicit"])
-    allow(Doorkeeper.configuration).to receive(:authenticate_resource_owner).and_return(->(_) { authenticator_method })
+    allow(Doorkeeper.config).to receive(:grant_flows).and_return(["implicit"])
+    allow(Doorkeeper.config).to receive(:authenticate_resource_owner).and_return(->(_) { authenticator_method })
     allow(controller).to receive(:authenticator_method).and_return(user)
     expect(controller).to receive(:authenticator_method).at_most(:once)
   end
@@ -69,7 +69,7 @@ def query_params
 
   describe "POST #create in API mode" do
     before do
-      allow(Doorkeeper.configuration).to receive(:api_only).and_return(true)
+      allow(Doorkeeper.config).to receive(:api_only).and_return(true)
       post :create, params: { client_id: client.uid, response_type: "token", redirect_uri: client.redirect_uri }
     end
 
@@ -177,7 +177,7 @@ def query_params
   describe "POST #create in API mode with errors" do
     context "when missing client_id" do
       before do
-        allow(Doorkeeper.configuration).to receive(:api_only).and_return(true)
+        allow(Doorkeeper.config).to receive(:api_only).and_return(true)
 
         post :create, params: {
           client_id: "",
@@ -209,7 +209,7 @@ def query_params
 
     context "when other error happens" do
       before do
-        allow(Doorkeeper.configuration).to receive(:api_only).and_return(true)
+        allow(Doorkeeper.config).to receive(:api_only).and_return(true)
         default_scopes_exist :public
 
         post :create, params: {
@@ -251,7 +251,7 @@ def query_params
 
   describe "POST #create with application already authorized" do
     before do
-      allow(Doorkeeper.configuration).to receive(:reuse_access_token).and_return(true)
+      allow(Doorkeeper.config).to receive(:reuse_access_token).and_return(true)
 
       access_token.save!
 
@@ -286,12 +286,12 @@ def query_params
       end
 
       it "should call :before_successful_authorization callback" do
-        expect(Doorkeeper.configuration)
+        expect(Doorkeeper.config)
           .to receive_message_chain(:before_successful_authorization, :call).with(instance_of(described_class))
       end
 
       it "should call :after_successful_authorization callback" do
-        expect(Doorkeeper.configuration)
+        expect(Doorkeeper.config)
           .to receive_message_chain(:after_successful_authorization, :call).with(instance_of(described_class))
       end
     end
@@ -302,18 +302,18 @@ def query_params
       end
 
       it "should not call :before_successful_authorization callback" do
-        expect(Doorkeeper.configuration).not_to receive(:before_successful_authorization)
+        expect(Doorkeeper.config).not_to receive(:before_successful_authorization)
       end
 
       it "should not call :after_successful_authorization callback" do
-        expect(Doorkeeper.configuration).not_to receive(:after_successful_authorization)
+        expect(Doorkeeper.config).not_to receive(:after_successful_authorization)
       end
     end
   end
 
   describe "GET #new token request with native url and skip_authorization true" do
     before do
-      allow(Doorkeeper.configuration).to receive(:skip_authorization).and_return(proc do
+      allow(Doorkeeper.config).to receive(:skip_authorization).and_return(proc do
         true
       end)
 
@@ -342,8 +342,8 @@ def query_params
 
   describe "GET #new code request with native url and skip_authorization true" do
     before do
-      allow(Doorkeeper.configuration).to receive(:grant_flows).and_return(%w[authorization_code])
-      allow(Doorkeeper.configuration).to receive(:skip_authorization).and_return(proc do
+      allow(Doorkeeper.config).to receive(:grant_flows).and_return(%w[authorization_code])
+      allow(Doorkeeper.config).to receive(:skip_authorization).and_return(proc do
         true
       end)
 
@@ -373,7 +373,7 @@ def query_params
 
   describe "GET #new with skip_authorization true" do
     before do
-      allow(Doorkeeper.configuration).to receive(:skip_authorization).and_return(proc do
+      allow(Doorkeeper.config).to receive(:skip_authorization).and_return(proc do
         true
       end)
 
@@ -412,7 +412,7 @@ def query_params
 
   describe "GET #new in API mode" do
     before do
-      allow(Doorkeeper.configuration).to receive(:api_only).and_return(true)
+      allow(Doorkeeper.config).to receive(:api_only).and_return(true)
 
       get :new, params: {
         client_id: client.uid,
diff --git a/spec/lib/doorkeeper_spec.rb b/spec/lib/doorkeeper_spec.rb
index 062b3cd4c..04d44c77e 100644
--- a/spec/lib/doorkeeper_spec.rb
+++ b/spec/lib/doorkeeper_spec.rb
@@ -7,7 +7,7 @@
     let(:request) { double }
 
     it "calls OAuth::Token#authenticate" do
-      token_strategies = Doorkeeper.configuration.access_token_methods
+      token_strategies = Doorkeeper.config.access_token_methods
 
       expect(Doorkeeper::OAuth::Token).to receive(:authenticate)
         .with(request, *token_strategies)