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"Functions that help with dynamically creating decorators for views."
import types
try:
from functools import wraps, update_wrapper, WRAPPER_ASSIGNMENTS
except ImportError:
from django.utils.functional import wraps, update_wrapper, WRAPPER_ASSIGNMENTS # Python 2.4 fallback.
def method_decorator(decorator):
"""
Converts a function decorator into a method decorator
"""
def _dec(func):
def _wrapper(self, *args, **kwargs):
def bound_func(*args2, **kwargs2):
return func(self, *args2, **kwargs2)
# bound_func has the signature that 'decorator' expects i.e. no
# 'self' argument, but it is a closure over self so it can call
# 'func' correctly.
return decorator(bound_func)(*args, **kwargs)
return wraps(func)(_wrapper)
update_wrapper(_dec, decorator)
# Change the name to aid debugging.
_dec.__name__ = 'method_decorator(%s)' % decorator.__name__
return _dec
def decorator_from_middleware_with_args(middleware_class):
"""
Like decorator_from_middleware, but returns a function
that accepts the arguments to be passed to the middleware_class.
Use like::
cache_page = decorator_from_middleware_with_args(CacheMiddleware)
# ...
@cache_page(3600)
def my_view(request):
# ...
"""
return make_middleware_decorator(middleware_class)
def decorator_from_middleware(middleware_class):
"""
Given a middleware class (not an instance), returns a view decorator. This
lets you use middleware functionality on a per-view basis. The middleware
is created with no params passed.
"""
return make_middleware_decorator(middleware_class)()
def available_attrs(fn):
"""
Return the list of functools-wrappable attributes on a callable.
This is required as a workaround for http://bugs.python.org/issue3445.
"""
return tuple(a for a in WRAPPER_ASSIGNMENTS if hasattr(fn, a))
def make_middleware_decorator(middleware_class):
def _make_decorator(*m_args, **m_kwargs):
middleware = middleware_class(*m_args, **m_kwargs)
def _decorator(view_func):
def _wrapped_view(request, *args, **kwargs):
if hasattr(middleware, 'process_request'):
result = middleware.process_request(request)
if result is not None:
return result
if hasattr(middleware, 'process_view'):
result = middleware.process_view(request, view_func, args, kwargs)
if result is not None:
return result
try:
response = view_func(request, *args, **kwargs)
except Exception, e:
if hasattr(middleware, 'process_exception'):
result = middleware.process_exception(request, e)
if result is not None:
return result
raise
if hasattr(middleware, 'process_response'):
result = middleware.process_response(request, response)
if result is not None:
return result
return response
return wraps(view_func, assigned=available_attrs(view_func))(_wrapped_view)
return _decorator
return _make_decorator
|
