Flows no longer need to be saved between uses.
Also introduces util.positional declarations.
Reviewed in http://codereview.appspot.com/6441056/.
Fixes issue #136.
diff --git a/oauth2client/util.py b/oauth2client/util.py
new file mode 100644
index 0000000..bda14c6
--- /dev/null
+++ b/oauth2client/util.py
@@ -0,0 +1,127 @@
+#!/usr/bin/env python
+#
+# Copyright 2010 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+"""Common utility library."""
+
+__author__ = ['rafek@google.com (Rafe Kaplan)',
+ 'guido@google.com (Guido van Rossum)',
+]
+__all__ = [
+ 'positional',
+]
+
+import gflags
+import inspect
+import logging
+
+logger = logging.getLogger(__name__)
+
+FLAGS = gflags.FLAGS
+
+gflags.DEFINE_enum('positional_parameters_enforcement', 'WARNING',
+ ['EXCEPTION', 'WARNING', 'IGNORE'],
+ 'The action when an oauth2client.util.positional declaration is violated.')
+
+
+def positional(max_positional_args):
+ """A decorator to declare that only the first N arguments my be positional.
+
+ This decorator makes it easy to support Python 3 style key-word only
+ parameters. For example, in Python 3 it is possible to write:
+
+ def fn(pos1, *, kwonly1=None, kwonly1=None):
+ ...
+
+ All named parameters after * must be a keyword:
+
+ fn(10, 'kw1', 'kw2') # Raises exception.
+ fn(10, kwonly1='kw1') # Ok.
+
+ Example:
+ To define a function like above, do:
+
+ @positional(1)
+ def fn(pos1, kwonly1=None, kwonly2=None):
+ ...
+
+ If no default value is provided to a keyword argument, it becomes a required
+ keyword argument:
+
+ @positional(0)
+ def fn(required_kw):
+ ...
+
+ This must be called with the keyword parameter:
+
+ fn() # Raises exception.
+ fn(10) # Raises exception.
+ fn(required_kw=10) # Ok.
+
+ When defining instance or class methods always remember to account for
+ 'self' and 'cls':
+
+ class MyClass(object):
+
+ @positional(2)
+ def my_method(self, pos1, kwonly1=None):
+ ...
+
+ @classmethod
+ @positional(2)
+ def my_method(cls, pos1, kwonly1=None):
+ ...
+
+ The positional decorator behavior is controlled by the
+ --positional_parameters_enforcement flag. The flag may be set to 'EXCEPTION',
+ 'WARNING' or 'IGNORE' to raise an exception, log a warning, or do nothing,
+ respectively, if a declaration is violated.
+
+ Args:
+ max_positional_arguments: Maximum number of positional arguments. All
+ parameters after the this index must be keyword only.
+
+ Returns:
+ A decorator that prevents using arguments after max_positional_args from
+ being used as positional parameters.
+
+ Raises:
+ TypeError if a key-word only argument is provided as a positional parameter,
+ but only if the --positional_parameters_enforcement flag is set to
+ 'EXCEPTION'.
+ """
+ def positional_decorator(wrapped):
+ def positional_wrapper(*args, **kwargs):
+ if len(args) > max_positional_args:
+ plural_s = ''
+ if max_positional_args != 1:
+ plural_s = 's'
+ message = '%s() takes at most %d positional argument%s (%d given)' % (
+ wrapped.__name__, max_positional_args, plural_s, len(args))
+ if FLAGS.positional_parameters_enforcement == 'EXCEPTION':
+ raise TypeError(message)
+ elif FLAGS.positional_parameters_enforcement == 'WARNING':
+ logger.warning(message)
+ else: # IGNORE
+ pass
+ return wrapped(*args, **kwargs)
+ return positional_wrapper
+
+ if isinstance(max_positional_args, (int, long)):
+ return positional_decorator
+ else:
+ args, _, _, defaults = inspect.getargspec(max_positional_args)
+ return positional(len(args) - len(defaults))(max_positional_args)