class Faraday::Response::RaiseError

def on_complete(env)
  case env[:status]
  when 404
    raise Faraday::Error::ResourceNotFound, response_values(env)
  when 400...600
    raise Faraday::Error::ClientError, response_values(env)
  end
end

def response_values(env)
  {:status => env[:status], :headers => env[:response_headers], :body => env[:body]}
end