Serve yaml files as yaml instead of converting them to json

rswag-api/lib/rswag/api/middleware.rb

@@ -1,5 +1,6 @@
 require 'json'
 require 'yaml'
+require 'rack/mime'
 
 module Rswag
   module Api
@@ -17,11 +18,13 @@ module Rswag
         if env['REQUEST_METHOD'] == 'GET' && File.file?(filename)
           swagger = parse_file(filename)
           @config.swagger_filter.call(swagger, env) unless @config.swagger_filter.nil?
+          mime = Rack::Mime.mime_type(::File.extname(path), 'text/plain')
+          body = unload_swagger(filename, swagger)
 
           return [
             '200',
-            { 'Content-Type' => 'application/json' },
+            { 'Content-Type' => mime },
-            [ JSON.dump(swagger) ]
+            [ body ]
           ]
         end
 
@@ -45,6 +48,14 @@ module Rswag
       def load_json(filename)
         JSON.parse(File.read(filename))
       end
+
+      def unload_swagger(filename, swagger)
+        if /\.ya?ml$/ === filename
+          YAML.dump(swagger)
+        else
+          JSON.dump(swagger)
+        end
+      end
     end
   end
 end

rswag-api/spec/rswag/api/middleware_spec.rb

@@ -87,8 +87,8 @@ module Rswag
 
           it 'returns contents of the swagger file' do
             expect(response.length).to eql(3)
-            expect(response[1]).to include( 'Content-Type' => 'application/json')
+            expect(response[1]).to include( 'Content-Type' => 'text/yaml')
-            expect(response[2].join).to include('"title":"API V1"')
+            expect(response[2].join).to include('title: API V1')
           end
         end
       end

rswag-ui/lib/generators/rswag/ui/install/templates/rswag-ui.rb

@@ -2,9 +2,9 @@ Rswag::Ui.configure do |c|
 
   # List the Swagger endpoints that you want to be documented through the swagger-ui
   # The first parameter is the path (absolute or relative to the UI host) to the corresponding
-  # JSON endpoint and the second is a title that will be displayed in the document selector
+  # endpoint and the second is a title that will be displayed in the document selector
-  # NOTE: If you're using rspec-api to expose Swagger files (under swagger_root) as JSON endpoints,
+  # NOTE: If you're using rspec-api to expose Swagger files (under swagger_root) as JSON or YAML endpoints,
   # then the list below should correspond to the relative paths for those endpoints
 
-  c.swagger_endpoint '/api-docs/v1/swagger.json', 'API V1 Docs'
+  c.swagger_endpoint '/api-docs/v1/swagger.yaml', 'API V1 Docs'
 end