Dynamic registration (ruby-grape#2516)

* use `to_enum` instead of including `Enumerable` to attributes_iterator.rb and validation_errors.rb

* Remove unused build_coercer.rb

* Remove const_missing in api.rb

* Add Grape::Util::Registry
Add deregister module in spec

* Add Grape::Parser::Base and use Grape::Util::Registry

* Add Grape::Formatter::Base and use Grape::Util::Registry

* Add Grape::Middleware::Versioner::Base and use Grape::Util::Registry

* Add Grape::ErrorFormatter::Base and use Grape::Util::Registry

* Add Grape::Util::Registry to Grape::Validations
ContractScope validator has been moved to validations/validators and renamed properly

* Add `deregister in `before(:all)``

* Add `deregister` to Grape::Validations only

* Use `prepend`

* Fix Ruby 2.7
Fix rubocop

* Refactor collection_coercer_for
Refactor Grape::Validations::Types cache_key

* Add CHANGELOG.md

* Revert coercer_cache changes. Will do it another time

* Revert enumerable change

* Refactor registry

* Update CHANGELOG.md

Co-authored-by: Daniel (dB.) Doubrovkine <[email protected]>

---------

Co-authored-by: Daniel (dB.) Doubrovkine <[email protected]>

CHANGELOG.md

@@ -9,6 +9,7 @@
 * [#2512](https://github.com/ruby-grape/grape/pull/2512): Optimize hash alloc - [@ericproulx](https://github.com/ericproulx).
 * [#2513](https://github.com/ruby-grape/grape/pull/2513): Optimize Grape::Path - [@ericproulx](https://github.com/ericproulx).
 * [#2514](https://github.com/ruby-grape/grape/pull/2514): Add rails 8.0 to CI - [@ericproulx](https://github.com/ericproulx).
+* [#2516](https://github.com/ruby-grape/grape/pull/2516): Dynamic registration for parsers, formatters, versioners - [@ericproulx](https://github.com/ericproulx).
 * Your contribution here.
 
 #### Fixes

lib/grape/api.rb

@@ -78,15 +78,6 @@ def call(...)
         instance_for_rack.call(...)
       end
 
-      # Alleviates problems with autoloading by tring to search for the constant
-      def const_missing(*args)
-        if base_instance.const_defined?(*args)
-          base_instance.const_get(*args)
-        else
-          super
-        end
-      end
-
       # The remountable class can have a configuration hash to provide some dynamic class-level variables.
       # For instance, a description could be done using: `desc configuration[:description]` if it may vary
       # depending on where the endpoint is mounted. Use with care, if you find yourself using configuration

lib/grape/error_formatter.rb

@@ -2,22 +2,14 @@
 
 module Grape
   module ErrorFormatter
-    module_function
+    extend Grape::Util::Registry
 
-    DEFAULTS = {
-      serializable_hash: Grape::ErrorFormatter::Json,
-      json: Grape::ErrorFormatter::Json,
-      jsonapi: Grape::ErrorFormatter::Json,
-      txt: Grape::ErrorFormatter::Txt,
-      xml: Grape::ErrorFormatter::Xml
-    }.freeze
+    module_function
 
     def formatter_for(format, error_formatters = nil, default_error_formatter = nil)
-      select_formatter(error_formatters, format) || default_error_formatter || DEFAULTS[:txt]
-    end
+      return error_formatters[format] if error_formatters&.key?(format)
 
-    def select_formatter(error_formatters, format)
-      error_formatters&.key?(format) ? error_formatters[format] : DEFAULTS[format]
+      registry[format] || default_error_formatter || Grape::ErrorFormatter::Txt
     end
   end
 end

lib/grape/error_formatter/base.rb

@@ -2,36 +2,66 @@
 
 module Grape
   module ErrorFormatter
-    module Base
-      def present(message, env)
-        present_options = {}
-        presented_message = message
-        if presented_message.is_a?(Hash)
-          presented_message = presented_message.dup
-          present_options[:with] = presented_message.delete(:with)
+    class Base
+      class << self
+        def call(message, backtrace, options = {}, env = nil, original_exception = nil)
+          merge_backtrace = backtrace.present? && options.dig(:rescue_options, :backtrace)
+          merge_original_exception = original_exception && options.dig(:rescue_options, :original_exception)
+
+          wrapped_message = wrap_message(present(message, env))
+          if wrapped_message.is_a?(Hash)
+            wrapped_message[:backtrace] = backtrace if merge_backtrace
+            wrapped_message[:original_exception] = original_exception.inspect if merge_original_exception
+          end
+
+          format_structured_message(wrapped_message)
         end
 
-        presenter = env[Grape::Env::API_ENDPOINT].entity_class_for_obj(presented_message, present_options)
+        def present(message, env)
+          present_options = {}
+          presented_message = message
+          if presented_message.is_a?(Hash)
+            presented_message = presented_message.dup
+            present_options[:with] = presented_message.delete(:with)
+          end
+
+          presenter = env[Grape::Env::API_ENDPOINT].entity_class_for_obj(presented_message, present_options)
+
+          unless presenter || env[Grape::Env::GRAPE_ROUTING_ARGS].nil?
+            # env['api.endpoint'].route does not work when the error occurs within a middleware
+            # the Endpoint does not have a valid env at this moment
+            http_codes = env[Grape::Env::GRAPE_ROUTING_ARGS][:route_info].http_codes || []
+
+            found_code = http_codes.find do |http_code|
+              (http_code[0].to_i == env[Grape::Env::API_ENDPOINT].status) && http_code[2].respond_to?(:represent)
+            end if env[Grape::Env::API_ENDPOINT].request
 
-        unless presenter || env[Grape::Env::GRAPE_ROUTING_ARGS].nil?
-          # env['api.endpoint'].route does not work when the error occurs within a middleware
-          # the Endpoint does not have a valid env at this moment
-          http_codes = env[Grape::Env::GRAPE_ROUTING_ARGS][:route_info].http_codes || []
+            presenter = found_code[2] if found_code
+          end
 
-          found_code = http_codes.find do |http_code|
-            (http_code[0].to_i == env[Grape::Env::API_ENDPOINT].status) && http_code[2].respond_to?(:represent)
-          end if env[Grape::Env::API_ENDPOINT].request
+          if presenter
+            embeds = { env: env }
+            embeds[:version] = env[Grape::Env::API_VERSION] if env.key?(Grape::Env::API_VERSION)
+            presented_message = presenter.represent(presented_message, embeds).serializable_hash
+          end
 
-          presenter = found_code[2] if found_code
+          presented_message
         end
 
-        if presenter
-          embeds = { env: env }
-          embeds[:version] = env[Grape::Env::API_VERSION] if env.key?(Grape::Env::API_VERSION)
-          presented_message = presenter.represent(presented_message, embeds).serializable_hash
+        def wrap_message(message)
+          return message if message.is_a?(Hash)
+
+          { message: message }
+        end
+
+        def format_structured_message(_structured_message)
+          raise NotImplementedError
         end
 
-        presented_message
+        def inherited(klass)
+          super
+          ErrorFormatter.register(klass)
+        end
       end
     end
   end

lib/grape/error_formatter/json.rb

@@ -2,43 +2,26 @@
 
 module Grape
   module ErrorFormatter
-    module Json
-      extend Base
-
+    class Json < Base
       class << self
-        def call(message, backtrace, options = {}, env = nil, original_exception = nil)
-          result = wrap_message(present(message, env))
-
-          result = merge_rescue_options(result, backtrace, options, original_exception) if result.is_a?(Hash)
-
-          ::Grape::Json.dump(result)
+        def format_structured_message(structured_message)
+          ::Grape::Json.dump(structured_message)
         end
 
         private
 
         def wrap_message(message)
-          if message.is_a?(Hash)
-            message
-          elsif message.is_a?(Exceptions::ValidationErrors)
-            message.as_json
-          else
-            { error: ensure_utf8(message) }
-          end
+          return message if message.is_a?(Hash)
+          return message.as_json if message.is_a?(Exceptions::ValidationErrors)
+
+          { error: ensure_utf8(message) }
         end
 
         def ensure_utf8(message)
           return message unless message.respond_to? :encode
 
           message.encode('UTF-8', invalid: :replace, undef: :replace)
         end
-
-        def merge_rescue_options(result, backtrace, options, original_exception)
-          rescue_options = options[:rescue_options] || {}
-          result = result.merge(backtrace: backtrace) if rescue_options[:backtrace] && backtrace && !backtrace.empty?
-          result = result.merge(original_exception: original_exception.inspect) if rescue_options[:original_exception] && original_exception
-
-          result
-        end
       end
     end
   end

lib/grape/error_formatter/jsonapi.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module Grape
+  module ErrorFormatter
+    class Jsonapi < Json; end
+  end
+end

lib/grape/error_formatter/serializable_hash.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module Grape
+  module ErrorFormatter
+    class SerializableHash < Json; end
+  end
+end

lib/grape/error_formatter/txt.rb

@@ -2,26 +2,19 @@
 
 module Grape
   module ErrorFormatter
-    module Txt
-      extend Base
-
-      class << self
-        def call(message, backtrace, options = {}, env = nil, original_exception = nil)
-          message = present(message, env)
-
-          result = message.is_a?(Hash) ? ::Grape::Json.dump(message) : message
-          Array.wrap(result).tap do |final_result|
-            rescue_options = options[:rescue_options] || {}
-            if rescue_options[:backtrace] && backtrace.present?
-              final_result << 'backtrace:'
-              final_result.concat(backtrace)
-            end
-            if rescue_options[:original_exception] && original_exception
-              final_result << 'original exception:'
-              final_result << original_exception.inspect
-            end
-          end.join("\r\n ")
-        end
+    class Txt < Base
+      def self.format_structured_message(structured_message)
+        message = structured_message[:message] || Grape::Json.dump(structured_message)
+        Array.wrap(message).tap do |final_message|
+          if structured_message.key?(:backtrace)
+            final_message << 'backtrace:'
+            final_message.concat(structured_message[:backtrace])
+          end
+          if structured_message.key?(:original_exception)
+            final_message << 'original exception:'
+            final_message << structured_message[:original_exception]
+          end
+        end.join("\r\n ")
       end
     end
   end

lib/grape/error_formatter/xml.rb

@@ -2,19 +2,9 @@
 
 module Grape
   module ErrorFormatter
-    module Xml
-      extend Base
-
-      class << self
-        def call(message, backtrace, options = {}, env = nil, original_exception = nil)
-          message = present(message, env)
-
-          result = message.is_a?(Hash) ? message : { message: message }
-          rescue_options = options[:rescue_options] || {}
-          result = result.merge(backtrace: backtrace) if rescue_options[:backtrace] && backtrace && !backtrace.empty?
-          result = result.merge(original_exception: original_exception.inspect) if rescue_options[:original_exception] && original_exception
-          result.respond_to?(:to_xml) ? result.to_xml(root: :error) : result.to_s
-        end
+    class Xml < Base
+      def self.format_structured_message(structured_message)
+        structured_message.respond_to?(:to_xml) ? structured_message.to_xml(root: :error) : structured_message.to_s
       end
     end
   end

lib/grape/formatter.rb

@@ -2,24 +2,16 @@
 
 module Grape
   module Formatter
-    module_function
+    extend Grape::Util::Registry
 
-    DEFAULTS = {
-      json: Grape::Formatter::Json,
-      jsonapi: Grape::Formatter::Json,
-      serializable_hash: Grape::Formatter::SerializableHash,
-      txt: Grape::Formatter::Txt,
-      xml: Grape::Formatter::Xml
-    }.freeze
+    module_function
 
     DEFAULT_LAMBDA_FORMATTER = ->(obj, _env) { obj }
 
     def formatter_for(api_format, formatters)
-      select_formatter(formatters, api_format) || DEFAULT_LAMBDA_FORMATTER
-    end
+      return formatters[api_format] if formatters&.key?(api_format)
 
-    def select_formatter(formatters, api_format)
-      formatters&.key?(api_format) ? formatters[api_format] : DEFAULTS[api_format]
+      registry[api_format] || DEFAULT_LAMBDA_FORMATTER
     end
   end
 end

lib/grape/formatter/base.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+module Grape
+  module Formatter
+    class Base
+      def self.call(_object, _env)
+        raise NotImplementedError
+      end
+
+      def self.inherited(klass)
+        super
+        Formatter.register(klass)
+      end
+    end
+  end
+end

lib/grape/formatter/json.rb

@@ -2,13 +2,11 @@
 
 module Grape
   module Formatter
-    module Json
-      class << self
-        def call(object, _env)
-          return object.to_json if object.respond_to?(:to_json)
+    class Json < Base
+      def self.call(object, _env)
+        return object.to_json if object.respond_to?(:to_json)
 
-          ::Grape::Json.dump(object)
-        end
+        ::Grape::Json.dump(object)
       end
     end
   end

lib/grape/formatter/serializable_hash.rb

@@ -2,7 +2,7 @@
 
 module Grape
   module Formatter
-    module SerializableHash
+    class SerializableHash < Base
       class << self
         def call(object, _env)
           return object if object.is_a?(String)

lib/grape/formatter/txt.rb

@@ -2,11 +2,9 @@
 
 module Grape
   module Formatter
-    module Txt
-      class << self
-        def call(object, _env)
-          object.respond_to?(:to_txt) ? object.to_txt : object.to_s
-        end
+    class Txt < Base
+      def self.call(object, _env)
+        object.respond_to?(:to_txt) ? object.to_txt : object.to_s
       end
     end
   end

lib/grape/formatter/xml.rb

@@ -2,13 +2,11 @@
 
 module Grape
   module Formatter
-    module Xml
-      class << self
-        def call(object, _env)
-          return object.to_xml if object.respond_to?(:to_xml)
+    class Xml < Base
+      def self.call(object, _env)
+        return object.to_xml if object.respond_to?(:to_xml)
 
-          raise Grape::Exceptions::InvalidFormatter.new(object.class, 'xml')
-        end
+        raise Grape::Exceptions::InvalidFormatter.new(object.class, 'xml')
       end
     end
   end

lib/grape/middleware/versioner.rb

@@ -11,14 +11,16 @@
 module Grape
   module Middleware
     module Versioner
+      extend Grape::Util::Registry
+
       module_function
 
       # @param strategy [Symbol] :path, :header, :accept_version_header or :param
       # @return a middleware class based on strategy
       def using(strategy)
-        Grape::Middleware::Versioner.const_get(:"#{strategy.to_s.camelize}")
-      rescue NameError
-        raise Grape::Exceptions::InvalidVersionerOption, strategy
+        raise Grape::Exceptions::InvalidVersionerOption, strategy unless registry.key?(strategy)
+
+        registry[strategy]
       end
     end
   end