class Rack::MediaType

def params(content_type)

{ 'charset' => 'utf-8' }
this method responds with the following Hash:
provided. e.g., when the CONTENT_TYPE is "text/plain;charset=utf-8",
an empty Hash if no CONTENT_TYPE or media-type parameters were
The media type parameters provided in CONTENT_TYPE as a Hash, or 
def params(content_type)
  return {} if content_type.nil?
  content_type.split(SPLIT_PATTERN)[1..-1].each_with_object({}) do |s, hsh|
    k, v = s.split('=', 2)
    hsh[k.tap(&:downcase!)] = strip_doublequotes(v)
  end
end