Can a decorator of an instance method access the class?

Question

I have something roughly like the following. Basically I need to access the class of an instance method from a decorator used upon the instance method in its definition.

Answer 1

What flask-classy does is create a temporary cache that it stores on the method, then it uses something else (the fact that Flask will register the classes using a register class method) to actually wraps the method.

You can reuse this pattern, this time using a metaclass so that you can wrap the method at import time.

def route(rule, **options):
    """A decorator that is used to define custom routes for methods in
    FlaskView subclasses. The format is exactly the same as Flask's
    `@app.route` decorator.
    """

    def decorator(f):
        # Put the rule cache on the method itself instead of globally
        if not hasattr(f, '_rule_cache') or f._rule_cache is None:
            f._rule_cache = {f.__name__: [(rule, options)]}
        elif not f.__name__ in f._rule_cache:
            f._rule_cache[f.__name__] = [(rule, options)]
        else:
            f._rule_cache[f.__name__].append((rule, options))

        return f

    return decorator

On the actual class (you could do the same using a metaclass):

@classmethod
def register(cls, app, route_base=None, subdomain=None, route_prefix=None,
             trailing_slash=None):

    for name, value in members:
        proxy = cls.make_proxy_method(name)
        route_name = cls.build_route_name(name)
        try:
            if hasattr(value, "_rule_cache") and name in value._rule_cache:
                for idx, cached_rule in enumerate(value._rule_cache[name]):
                    # wrap the method here

Source: https://github.com/apiguy/flask-classy/blob/master/flask_classy.py