Adds a credential class that supports User Refresh Tokens

lib/googleauth/user_refresh.rb

@@ -0,0 +1,76 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+require 'googleauth/signet'
+require 'googleauth/credentials_loader'
+require 'multi_json'
+
+module Google
+  # Module Auth provides classes that provide Google-specific authorization
+  # used to access Google APIs.
+  module Auth
+    # Authenticates requests using User Refresh credentials.
+    #
+    # This class allows authorizing requests from user refresh tokens.
+    #
+    # This the end of the result of a 3LO flow.  E.g, the end result of
+    # 'gcloud auth login' saves a file with these contents in well known
+    # location
+    #
+    # cf [Application Default Credentials](http://goo.gl/mkAHpZ)
+    class UserRefreshCredentials < Signet::OAuth2::Client
+      TOKEN_CRED_URI = 'https://www.googleapis.com/oauth2/v3/token'
+      extend CredentialsLoader
+
+      # Reads the client_id, client_secret and refresh_token fields from the
+      # JSON key.
+      def self.read_json_key(json_key_io)
+        json_key = MultiJson.load(json_key_io.read)
+        wanted = %w(client_id client_secret refresh_token)
+        wanted.each do |key|
+          fail "the json is missing the #{key} field" unless json_key.key?(key)
+        end
+        json_key
+      end
+
+      # Initializes a UserRefreshCredentials.
+      #
+      # @param scope [string|array] the scope(s) to access
+      # @param json_key_io [IO] an IO from which the JSON key can be read
+      def initialize(scope, json_key_io)
+        user_creds = self.class.read_json_key(json_key_io)
+        super(token_credential_uri: TOKEN_CRED_URI,
+              client_id: user_creds['client_id'],
+              client_secret: user_creds['client_secret'],
+              refresh_token: user_creds['refresh_token'],
+              scope: scope)
+      end
+    end
+  end
+end