def decorator(func):\n @functools.wraps(func)\n def wrapper(*args, **kwargs):\n return func(*args, **kwargs)\n return wrapper

Decorators & Metaclasses

Meaning

A minimal decorator that preserves the original function's metadata while transparently forwarding all arguments and return values.

Primary Function

Creates a transparent wrapper that forwards calls to the original function while preserving its name, docstring, and other attributes via functools.wraps.

Communicative Purpose

Defines a reusable pattern for adding behavior before/after a function call without altering its interface.

Função primária

Creates a transparent wrapper that forwards calls to the original function while preserving its name, docstring, and other attributes via functools.wraps.

Propósito comunicativo

Defines a reusable pattern for adding behavior before/after a function call without altering its interface.

Situações de gatilho

When you need to add logging, timing, authentication, or any cross‑cutting concern to a function without modifying its source.

Contextos

Used in library code, framework middleware, or application utilities where transparent wrapping is required.

Família do chunk

decorator pattern
wrapper pattern
functools.wraps

Upgrade path

Learn to add preprocessing/post‑processing logic inside the wrapper (e.g., logging, timing, validation).

Tag de espaçamento: Medium-term

Examples

def timer(func): @functools.wraps(func) def wrapper(*args, **kwargs): start = time.perf_counter() result = func(*args, **kwargs) elapsed = time.perf_counter() - start print(f'{func.__name__} took {elapsed:.4f}s') return result return wrapper @timer def process(data): return sum(data)

def retry(max_attempts=3): def decorator(func): @functools.wraps(func) def wrapper(*args, **kwargs): for attempt in range(max_attempts): try: return func(*args, **kwargs) except Exception: if attempt == max_attempts - 1: raise return wrapper return decorator @retry(max_attempts=5) def fetch(url): return requests.get(url).json()

def debug(func): @functools.wraps(func) def wrapper(*args, **kwargs): args_repr = [repr(a) for a in args] kwargs_repr = [f'{k}={v!r}' for k, v in kwargs.items()] signature = ', '.join(args_repr + kwargs_repr) print(f'Calling {func.__name__}({signature})') result = func(*args, **kwargs) print(f'{func.__name__} returned {result!r}') return result return wrapper @debug def greet(name, greeting='Hello'): return f'{greeting}, {name}!'