app/django/utils/decorators.py
author Pawel Solyga <Pawel.Solyga@gmail.com>
Mon, 01 Jun 2009 22:23:46 +0200
changeset 2376 feec28b50f1b
parent 54 03e267d67478
permissions -rw-r--r--
Extend taggable-mixin to support different Tag models. Usage is pretty simple. Tag model is default in Taggable constructor but you can call it with different model like GHOPTaskType that inherits from Tag model. Both Taggable and Tag models have been updated and they don't use hardcoded Tag model anymore and instead use cls of class methods or self.__class__. In case of Taggable it's self.__tag_model.

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

import types
try:
    from functools import wraps
except ImportError:
    from django.utils.functional import wraps  # Python 2.3, 2.4 fallback.

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.
    """
    def _decorator_from_middleware(*args, **kwargs):
        # For historical reasons, these "decorators" are also called as
        # dec(func, *args) instead of dec(*args)(func). We handle both forms
        # for backwards compatibility.
        has_func = True
        try:
            view_func = kwargs.pop('view_func')
        except KeyError:
            if len(args):
                view_func, args = args[0], args[1:]
            else:
                has_func = False
        if not (has_func and isinstance(view_func, types.FunctionType)):
            # We are being called as a decorator.
            if has_func:
                args = (view_func,) + args
            middleware = middleware_class(*args, **kwargs)

            def decorator_func(fn):
                return _decorator_from_middleware(fn, *args, **kwargs)
            return decorator_func

        middleware = middleware_class(*args, **kwargs)

        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)(_wrapped_view)
    return _decorator_from_middleware