Content types registrable

CHANGELOG.md

@@ -3,6 +3,7 @@
 #### Features
 
 * Your contribution here.
+* [#2005](https://github.com/ruby-grape/grape/pull/2005): Content types registrable - [@ericproulx](https://github.com/ericproulx).
 * [#2003](https://github.com/ruby-grape/grape/pull/2003): Upgraded Rubocop to 0.80.1 - [@ericproulx](https://github.com/ericproulx).
 * [#2002](https://github.com/ruby-grape/grape/pull/2002): Objects allocation optimization (lazy_lookup) - [@ericproulx](https://github.com/ericproulx).
 

lib/grape.rb

@@ -218,7 +218,8 @@ module ServeFile
 end
 
 require 'grape/config'
-require 'grape/util/content_types'
+require 'grape/content_types'
+
 require 'grape/util/lazy_value'
 require 'grape/util/lazy_block'
 require 'grape/util/endpoint_configuration'

lib/grape/content_types.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require 'grape/util/registrable'
+
+module Grape
+  module ContentTypes
+    extend Util::Registrable
+
+    # Content types are listed in order of preference.
+    CONTENT_TYPES = {
+      xml: 'application/xml',
+      serializable_hash: 'application/json',
+      json: 'application/json',
+      binary: 'application/octet-stream',
+      txt: 'text/plain'
+    }.freeze
+
+    class << self
+      def content_types_for_settings(settings)
+        return if settings.blank?
+
+        settings.each_with_object({}) { |value, result| result.merge!(value) }
+      end
+
+      def content_types_for(from_settings)
+        if from_settings.present?
+          from_settings
+        else
+          Grape::ContentTypes::CONTENT_TYPES.merge(default_elements)
+        end
+      end
+    end
+  end
+end

spec/grape/middleware/formatter_spec.rb

@@ -402,10 +402,10 @@ def self.call(_, _)
     let(:app) { ->(_env) { [200, {}, ['']] } }
     before do
       Grape::Formatter.register :invalid, InvalidFormatter
-      Grape::ContentTypes::CONTENT_TYPES[:invalid] = 'application/x-invalid'
+      Grape::ContentTypes.register :invalid, 'application/x-invalid'
     end
     after do
-      Grape::ContentTypes::CONTENT_TYPES.delete(:invalid)
+      Grape::ContentTypes.default_elements.delete(:invalid)
       Grape::Formatter.default_elements.delete(:invalid)
     end