35a1b89292
If a URI template defines fields that do not have corresponding args in a given resource's on_* responder, return method not allowed for that route. Closes #95
142 lines
4.8 KiB
Python
142 lines
4.8 KiB
Python
"""Defines Falcon hooks
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Copyright 2013 by Rackspace Hosting, Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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"""
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from functools import wraps
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import inspect
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import six
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from falcon import HTTP_METHODS
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def before(action):
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"""Decorator to execute the given action function *before* the responder.
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Args:
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action: A function with a similar signature to a resource responder
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method, taking (req, resp, params), where params includes values for
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URI template field names, if any. Hooks may also add pseudo-params
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of their own. For example:
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def do_something(req, resp, params):
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try:
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params['id'] = int(params['id'])
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except ValueError:
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raise falcon.HTTPBadRequest('Invalid ID',
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'ID was not valid.')
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params['answer'] = 42
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"""
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def _before(responder_or_resource):
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if isinstance(responder_or_resource, six.class_types):
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resource = responder_or_resource
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for method in HTTP_METHODS:
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responder_name = 'on_' + method.lower()
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try:
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responder = getattr(resource, responder_name)
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except AttributeError:
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# resource does not implement this method
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pass
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else:
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# Usually expect a method, but any callable will do
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if hasattr(responder, '__call__'):
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# This pattern is necessary to capture the current
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# value of responder in the do_before_all closure;
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# otherwise, they will capture the same responder
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# variable that is shared between iterations of the
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# for loop, above.
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def let(responder=responder):
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@wraps(responder)
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def do_before_all(self, req, resp, **kwargs):
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action(req, resp, kwargs)
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responder(self, req, resp, **kwargs)
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argspec = inspect.getargspec(responder)
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do_before_all.wrapped_argspec = argspec
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setattr(resource, responder_name, do_before_all)
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let()
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return resource
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else:
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responder = responder_or_resource
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@wraps(responder)
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def do_before_one(self, req, resp, **kwargs):
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action(req, resp, kwargs)
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responder(self, req, resp, **kwargs)
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return do_before_one
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return _before
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def after(action):
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"""Decorator to execute the given action function *after* the responder.
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Args:
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action: A function with a similar signature to a resource responder
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method, taking (req, resp).
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"""
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def _after(responder_or_resource):
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if isinstance(responder_or_resource, six.class_types):
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resource = responder_or_resource
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for method in HTTP_METHODS:
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responder_name = 'on_' + method.lower()
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try:
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responder = getattr(resource, responder_name)
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except AttributeError:
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# resource does not implement this method
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pass
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else:
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# Usually expect a method, but any callable will do
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if hasattr(responder, '__call__'):
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def let(responder=responder):
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@wraps(responder)
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def do_after_all(self, req, resp, **kwargs):
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responder(self, req, resp, **kwargs)
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action(req, resp)
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argspec = inspect.getargspec(responder)
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do_after_all.wrapped_argspec = argspec
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setattr(resource, responder_name, do_after_all)
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let()
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return resource
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else:
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responder = responder_or_resource
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@wraps(responder)
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def do_after_one(self, req, resp, **kwargs):
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responder(self, req, resp, **kwargs)
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action(req, resp)
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return do_after_one
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return _after
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