google-auth-library-ruby/lib/googleauth/signet.rb

# Copyright 2015, Google Inc.
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require "signet/oauth_2/client"

module Signet
  # OAuth2 supports OAuth2 authentication.
  module OAuth2
    AUTH_METADATA_KEY = :authorization
    # Signet::OAuth2::Client creates an OAuth2 client
    #
    # This reopens Client to add #apply and #apply! methods which update a
    # hash with the fetched authentication token.
    class Client
      def configure_connection options
        @connection_info =
          options[:connection_builder] || options[:default_connection]
        self
      end

      # Updates a_hash updated with the authentication token
      def apply! a_hash, opts = {}
        # fetch the access token there is currently not one, or if the client
        # has expired
        fetch_access_token! opts if access_token.nil? || expires_within?(60)
        a_hash[AUTH_METADATA_KEY] = "Bearer #{access_token}"
      end

      # Returns a clone of a_hash updated with the authentication token
      def apply a_hash, opts = {}
        a_copy = a_hash.clone
        apply! a_copy, opts
        a_copy
      end

      # Returns a reference to the #apply method, suitable for passing as
      # a closure
      def updater_proc
        lambda(&method(:apply))
      end

      def on_refresh &block
        @refresh_listeners = [] unless defined? @refresh_listeners
        @refresh_listeners << block
      end

      alias orig_fetch_access_token! fetch_access_token!
      def fetch_access_token! options = {}
        unless options[:connection]
          connection = build_default_connection
          options = options.merge connection: connection if connection
        end
        info = retry_with_error do
          orig_fetch_access_token! options
        end
        notify_refresh_listeners
        info
      end

      def notify_refresh_listeners
        listeners = defined?(@refresh_listeners) ? @refresh_listeners : []
        listeners.each do |block|
          block.call self
        end
      end

      def build_default_connection
        if !defined?(@connection_info)
          nil
        elsif @connection_info.respond_to? :call
          @connection_info.call
        else
          @connection_info
        end
      end

      def retry_with_error max_retry_count = 5
        retry_count = 0

        begin
          yield
        rescue StandardError => e
          raise e if e.is_a?(Signet::AuthorizationError) || e.is_a?(Signet::ParseError)

          if retry_count < max_retry_count
            retry_count += 1
            sleep retry_count * 0.3
            retry
          else
            msg = "Unexpected error: #{e.inspect}"
            raise Signet::AuthorizationError, msg
          end
        end
      end
    end
  end
end