fix content type split/parsing, using racks implementation

lib/committee/schema_validator.rb

@@ -4,7 +4,7 @@ module Committee
   module SchemaValidator
     class << self
       def request_media_type(request)
-        request.media_type.to_s
+        Rack::MediaType.type(request.env['CONTENT_TYPE'])
       end
 
       # @param [String] prefix

lib/committee/schema_validator/open_api_3/operation_wrapper.rb

@@ -111,7 +111,7 @@ def validate_get_request_params(path_params, query_params, headers, validator_op
 
         def validate_post_request_params(path_params, query_params, body_params, headers, validator_option)
           content_type_key = headers.keys.detect { |k| k.casecmp?('Content-Type') }
-          content_type = headers[content_type_key].to_s.split(';').first.to_s
+          content_type = Rack::MediaType.type(headers[content_type_key])
 
           # bad performance because when we coerce value, same check
           validate_path_and_query_params(path_params, query_params, headers, validator_option)

test/schema_validator_test.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+describe Committee::SchemaValidator do
+  it "parses simple content types" do
+    request = Rack::Request.new({ "CONTENT_TYPE" => "application/json" })
+    media_type = Committee::SchemaValidator.request_media_type(request)
+    assert_equal 'application/json', media_type
+  end
+
+  it "parses comma-delineated content types" do
+    request = Rack::Request.new({ "CONTENT_TYPE" => "multipart/form-data, application/json" })
+    media_type = Committee::SchemaValidator.request_media_type(request)
+    assert_equal 'multipart/form-data', media_type
+  end
+
+  it "parses semicolon-delineated content types" do
+    request = Rack::Request.new({ "CONTENT_TYPE" => "multipart/form-data; application/json" })
+    media_type = Committee::SchemaValidator.request_media_type(request)
+    assert_equal 'multipart/form-data', media_type
+  end
+end