zope-cachedescriptors

from zope.cachedescriptors.property import CachedProperty from zope.cachedescriptors.method import cached import time class DataFetcher: def __init__(self, id_val): self.id = id_val self._fetch_count = 0 @CachedProperty def expensive_property(self): self._fetch_count += 1 print(f" [Property] Fetching data for {self.id}... (call {self._fetch_count})") time.sleep(0.1) # Simulate network delay return f"Data for {self.id}-{time.time()}" @cached def expensive_method(self, param): self._fetch_count += 1 print(f" [Method] Fetching data for {self.id} with param {param}... (call {self._fetch_count})") time.sleep(0.1) # Simulate network delay return f"Result for {self.id}-{param}-{time.time()}" # Example Usage fetcher = DataFetcher("user123") print("--- CachedProperty Demo ---") result1 = fetcher.expensive_property print(f"Property 1: {result1}") result2 = fetcher.expensive_property # Should be cached print(f"Property 2: {result2}") assert result1 == result2 # Invalidate the property cache by deleting the attribute del fetcher.expensive_property result3 = fetcher.expensive_property # Should re-calculate print(f"Property 3 (after invalidation): {result3}") assert result1 != result3 print("\n--- CachedMethod Demo ---") method_result1 = fetcher.expensive_method("report_a") print(f"Method 1: {method_result1}") method_result2 = fetcher.expensive_method("report_a") # Should be cached print(f"Method 2: {method_result2}") assert method_result1 == method_result2 # Invalidate a specific method call with arguments fetcher.expensive_method.invalidate(fetcher, "report_a") method_result3 = fetcher.expensive_method("report_a") # Should re-calculate print(f"Method 3 (after invalidation): {method_result3}") assert method_result1 != method_result3 method_result4 = fetcher.expensive_method("report_b") # New argument, new cache entry print(f"Method 4: {method_result4}")