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# -*- coding: utf8 -*-
#
# 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.
import functools
import inspect
import horizon.exceptions
def handle_errors(error_message, error_default=None, request_arg=None):
"""A decorator for adding default error handling to API calls.
It wraps the original method in a try-except block, with horizon's
error handling added.
Note: it should only be used on functions or methods that take request as
their argument (it has to be named "request", or ``request_arg`` has to be
provided, indicating which argument is the request).
The decorated method accepts a number of additional parameters:
:param _error_handle: whether to handle the errors in this call
:param _error_message: override the error message
:param _error_default: override the default value returned on error
:param _error_redirect: specify a redirect url for errors
:param _error_ignore: ignore known errors
"""
def decorator(func):
# XXX This is an ugly hack for finding the 'request' argument.
if request_arg is None:
for _request_arg, name in enumerate(inspect.getargspec(func).args):
if name == 'request':
break
else:
raise RuntimeError(
"The handle_errors decorator requires 'request' as "
"an argument of the function or method being decorated")
else:
_request_arg = request_arg
@functools.wraps(func)
def wrapper(*args, **kwargs):
_error_handle = kwargs.pop('_error_handle', True)
_error_message = kwargs.pop('_error_message', error_message)
_error_default = kwargs.pop('_error_default', error_default)
_error_redirect = kwargs.pop('_error_redirect', None)
_error_ignore = kwargs.pop('_error_ignore', False)
if not _error_handle:
return func(*args, **kwargs)
try:
return func(*args, **kwargs)
except Exception:
request = args[_request_arg]
horizon.exceptions.handle(request, _error_message,
ignore=_error_ignore,
redirect=_error_redirect)
return _error_default
wrapper.wrapped = func
return wrapper
return decorator
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