python - 有没有办法让 python 函数知道它在模块加载时被装饰了？

Question

举个例子:

def decorator(func): 
    def nested(*args, **kwargs):
        return func(*args, **kwargs)
    return nested

@decorator
def decorated(): pass

有没有办法让 decorated 知道它正在被装饰？

Answer 1

你可以使用一个使用ast.NodeVistor的装饰器来遍历函数的AST节点来寻找函数的装饰器。如果装饰器列表包含的不仅仅是装饰器检查器本身，那么您可以从装饰器节点中获取其他装饰器的详细信息:

import inspect
import ast
from textwrap import dedent

class CheckDecorators(ast.NodeVisitor):
    def visit_FunctionDef(self, node):
        if len(node.decorator_list) > 1:
            print("function '%s' is decorated by: %s" % (node.name, ', '.join(ast.dump(decorator) for decorator in node.decorator_list if not isinstance(decorator, ast.Name) or decorator.id != 'check_decorators')))

def check_decorators(func):
    CheckDecorators().visit(ast.parse(dedent(inspect.getsource(func))))
    return func

这样:

def decorator(func):
    def nested(*args, **kwargs):
        return func(*args, **kwargs)
    return nested

@decorator
@check_decorators
def decorated():
    pass

会输出:

function 'decorated' is decorated by: Name(id='decorator', ctx=Load())