class Excon::Middleware::RedirectFollower

def self.valid_parameter_keys
  [
    :redirects_remaining,
    :redirect_limit
  ]
end

def get_header(datum, header)
  _, header_value = datum[:response][:headers].detect do |key, value|
    key.casecmp(header) == 0
  end
  header_value
end

def request_call(datum)
  datum[:redirects_remaining] ||= datum[:redirect_limit] ||
                                  Excon::DEFAULT_REDIRECT_LIMIT
  @stack.request_call(datum)
end

def response_call(datum)
  if datum.has_key?(:response)
    case datum[:response][:status]
    when 301, 302, 303, 307, 308
      if datum[:redirects_remaining] <= 0
        raise Excon::Errors::TooManyRedirects
      end
      datum[:redirects_remaining] -= 1
      uri_parser = datum[:uri_parser] || Excon.defaults[:uri_parser]
      location = get_header(datum, 'Location')
      base_uri = Excon::Utils.request_uri(datum)
      uri = uri_parser.join(base_uri, location)
      # delete old/redirect response and remote_ip
      response = datum.delete(:response)
      datum.delete(:remote_ip)
      params = datum.dup
      params.delete(:connection)
      params.delete(:password)
      params.delete(:stack)
      params.delete(:user)
      if [301, 302, 303].include?(response[:status])
        params[:method] = :get
        params.delete(:body)
        params[:headers].delete('Content-Length')
      end
      params[:headers] = datum[:headers].dup
      params[:headers].delete('Authorization')
      params[:headers].delete('Proxy-Connection')
      params[:headers].delete('Proxy-Authorization')
      params[:headers].delete('Host')
      params.merge!(
        :scheme     => uri.scheme || datum[:scheme],
        :host       => uri.host   || datum[:host],
        :hostname   => uri.hostname || datum[:hostname],
        :port       => uri.port   || datum[:port],
        :path       => uri.path,
        :query      => uri.query
      )
      params.merge!(:user => Utils.unescape_uri(uri.user)) if uri.user
      params.merge!(:password => Utils.unescape_uri(uri.password)) if uri.password
      response = Excon::Connection.new(params).request
      datum.merge!({
        :remote_ip  => response.remote_ip,
        :response   => response.data
      })
    else
      @stack.response_call(datum)
    end
  else
    @stack.response_call(datum)
  end
end