1 "Functions that help with dynamically creating decorators for views."

     2 

     3 import types

     4 try:

     5     from functools import wraps

     6 except ImportError:

     7     from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.

     8 

     9 def decorator_from_middleware(middleware_class):

    10     """

    11     Given a middleware class (not an instance), returns a view decorator. This

    12     lets you use middleware functionality on a per-view basis.

    13     """

    14     def _decorator_from_middleware(*args, **kwargs):

    15         # For historical reasons, these "decorators" are also called as

    16         # dec(func, *args) instead of dec(*args)(func). We handle both forms

    17         # for backwards compatibility.

    18         has_func = True

    19         try:

    20             view_func = kwargs.pop('view_func')

    21         except KeyError:

    22             if len(args):

    23                 view_func, args = args[0], args[1:]

    24             else:

    25                 has_func = False

    26         if not (has_func and isinstance(view_func, types.FunctionType)):

    27             # We are being called as a decorator.

    28             if has_func:

    29                 args = (view_func,) + args

    30             middleware = middleware_class(*args, **kwargs)

    31 

    32             def decorator_func(fn):

    33                 return _decorator_from_middleware(fn, *args, **kwargs)

    34             return decorator_func

    35 

    36         middleware = middleware_class(*args, **kwargs)

    37 

    38         def _wrapped_view(request, *args, **kwargs):

    39             if hasattr(middleware, 'process_request'):

    40                 result = middleware.process_request(request)

    41                 if result is not None:

    42                     return result

    43             if hasattr(middleware, 'process_view'):

    44                 result = middleware.process_view(request, view_func, args, kwargs)

    45                 if result is not None:

    46                     return result

    47             try:

    48                 response = view_func(request, *args, **kwargs)

    49             except Exception, e:

    50                 if hasattr(middleware, 'process_exception'):

    51                     result = middleware.process_exception(request, e)

    52                     if result is not None:

    53                         return result

    54                 raise

    55             if hasattr(middleware, 'process_response'):

    56                 result = middleware.process_response(request, response)

    57                 if result is not None:

    58                     return result

    59             return response

    60         return wraps(view_func)(_wrapped_view)

    61     return _decorator_from_middleware