python修饰器各种实用方法

This page is meant to be a central repository of decorator code pieces, whether useful or not <wink>. It is NOT a page to discuss decorator syntax!

Feel free to add your suggestions. Please make sure example code conforms with PEP 8.

 

Contents

1. Creating Well-Behaved Decorators / "Decorator decorator"
2. Property Definition
3. Memoize
4. Alternate memoize as nested functions
5. Alternate memoize as dict subclass
6. Alternate memoize that stores cache between executions
7. Cached Properties
8. Retry
9. Pseudo-currying
10. Creating decorator with optional arguments
11. Controllable DIY debug
12. Easy adding methods to a class instance
13. Counting function calls
14. Alternate Counting function calls
15. Generating Deprecation Warnings
16. Smart deprecation warnings (with valid filenames, line numbers, etc.)
17. Ignoring Deprecation Warnings
18. Enable/Disable Decorators
19. Easy Dump of Function Arguments
20. Pre-/Post-Conditions
21. Profiling/Coverage Analysis
22. Line Tracing Individual Functions
23. Synchronization
24. Type Enforcement (accepts/returns)
25. CGI method wrapper
26. State Machine Implementaion
27. C++/Java-keyword-like function decorators
28. Different Decorator Forms
29. Unimplemented function replacement
30. Redirects stdout printing to python standard logging.
31. Access control
32. Events rising and handling
33. Singleton
34. The Sublime Singleton
35. Asynchronous Call
36. Class method decorator using instance
37. Another Retrying Decorator
38. Logging decorator with specified logger (or default)
39. Lazy Thunkify
40. Aggregative decorators for generator functions
41. Function Timeout

 

Note: This is only one recipe. Others include inheritance from a standard decorator (link?), the functools @wraps decorator, and a factory function such as Michele Simionato's decorator module which even preserves signature information.

 

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   1 decorator):
   2 '''This decorator can be used to turn simple functions
   3     into well-behaved decorators, so long as the decorators
   4     are fairly simple. If a decorator expects a function and
   5     returns a function (no descriptors), and if it doesn't
   6     modify function attributes or docstring, then it is
   7     eligible to use this. Simply apply @simple_decorator to
   8     your decorator and it will automatically preserve the
   9     docstring and function attributes of functions to which
  10     it is applied.'''
  11 f):
  12 f)
  13 __name__
  14 __doc__
  15 __dict__)
  16 g
  17 # Now a few lines needed to make simple_decorator itself
  18 # be a well-behaved decorator.
  19 __name__
  20 __doc__
  21 __dict__)
  22 new_decorator
  23 
  24 #
  25 # Sample Use:
  26 #
  27 @simple_decorator
  28 func):
  29 kwargs):
  30 __name__)
  31 kwargs)
  32 you_will_never_see_this_name
  33 
  34 @my_simple_logging_decorator
  35 x):
  36 '
  37 x
  38 
  39 __name__ ==