feature: Add generator for initializer

lib/generators/doorkeeper/openid_connect/install_generator.rb

@@ -0,0 +1,11 @@
+class Doorkeeper::OpenidConnect::InstallGenerator < ::Rails::Generators::Base
+  include Rails::Generators::Migration
+  source_root File.expand_path('../templates', __FILE__)
+  desc 'Installs Doorkeeper OpenID Connect.'
+
+  def install
+    template 'initializer.rb', 'config/initializers/doorkeeper_openid_connect.rb'
+    copy_file File.expand_path('../../../../../config/locales/en.yml', __FILE__), 'config/locales/doorkeeper_openid_connect.en.yml'
+    route 'use_doorkeeper_openid_connect'
+  end
+end

lib/generators/doorkeeper/openid_connect/templates/initializer.rb

@@ -0,0 +1,41 @@
+Doorkeeper::OpenidConnect.configure do
+
+  issuer 'issuer string'
+
+  jws_private_key <<-EOL
+-----BEGIN RSA PRIVATE KEY-----
+....
+-----END RSA PRIVATE KEY-----
+EOL
+
+  jws_public_key <<-EOL
+-----BEGIN RSA PUBLIC KEY-----
+....
+-----END RSA PUBLIC KEY-----
+EOL
+
+  resource_owner_from_access_token do |access_token|
+    # Example implementation:
+    # User.find_by(id: access_token.resource_owner_id)
+  end
+
+  subject do |resource_owner|
+    # Example implementation:
+    # resource_owner.key
+  end
+
+  # Expiration time on or after which the ID Token MUST NOT be accepted for processing. (default 120 seconds).
+  # expiration 600
+
+  # Example claims:
+  # claims do
+  #   normal_claim :_foo_ do |resource_owner|
+  #     resource_owner.foo
+  #   end
+
+  #   normal_claim :_bar_ do |resource_owner|
+  #     resource_owner.bar
+  #   end
+  # end
+end
+