我正在尝试从类中的方法动态创建模块级函数。因此，对于一个类中的每个方法，我想创建一个同名的函数，它创建一个类的实例，然后调用该方法。
我想这样做的原因是我可以采用面向对象的方法来创建 Fabric 文件。由于 Fabric 将调用模块级函数而不是类的方法，因此这是我的解决方法。
我已使用以下链接开始
- 如何获取 Python 类中的方法列表？
- 向 Python 模块动态添加函数
- 如何在当前模块上调用 setattr()？
- http://effbot.org/zone/python-getattr.htm
- 在 Python 中从带有函数名称的字符串调用模块的函数
- 如何在python中修改本地命名空间
我想出了以下代码
import inspect
import sys
import types
class TestClass(object):
def __init__(self):
pass
def method1(self, arg1):
print 'method 1 %s' % arg1
def method2(self):
print 'method 2'
def fabric_class_to_function_magic(module_name):
# get the module as an object
print module_name
module_obj = sys.modules[module_name]
print dir(module_obj)
# Iterate over the methods of the class and dynamically create a function
# for each method that calls the method and add it to the current module
for method in inspect.getmembers(TestClass, predicate=inspect.ismethod):
print
print method
method_name, method_obj = method
# create a new template function which calls the method
def newfunc_template(*args, **kwargs):
tc = TestClass()
func = getattr(tc, method_name)
return func(*args, **kwargs)
# create the actual function
print 'code: ', newfunc_template.func_code
print 'method_name: ', method_name
newfunc = types.FunctionType(newfunc_template.func_code,
{'TestClass': TestClass,
'getattr': getattr,
'method_name': method_name,
},
name=method_name,
argdefs=newfunc_template.func_defaults,
closure=newfunc_template.func_closure,
)
# add the new function to the current module
setattr(module_obj, method_name, newfunc)
# test the dynamically created module level function
thismodule = sys.modules[__name__]
print dir(thismodule)
fabric_class_to_function_magic(__name__)
print dir(thismodule)
method1('arg1')
method2()
我收到以下错误
['TestClass', '__builtins__', '__doc__', '__file__', '__name__', '__package__', 'fabric_class_to_function_magic', 'inspect', 'sys', 'thismodule', 'types']
__main__
['TestClass', '__builtins__', '__doc__', '__file__', '__name__', '__package__', 'fabric_class_to_function_magic', 'inspect', 'sys', 'thismodule', 'types']
('__init__', <unbound method TestClass.__init__>)
code: <code object newfunc_template at 0x7f8800a28d50, file "test.py", line 85>
method_name: __init__
('method1', <unbound method TestClass.method1>)
code: <code object newfunc_template at 0x7f8800a28d50, file "test.py", line 85>
method_name: method1
('method2', <unbound method TestClass.method2>)
code: <code object newfunc_template at 0x7f8800a28d50, file "test.py", line 85>
method_name: method2
['TestClass', '__builtins__', '__doc__', '__file__', '__init__', '__name__', '__package__', 'fabric_class_to_function_magic', 'inspect', 'method1', 'method2', 'sys', 'thismodule', 'types']
Traceback (most recent call last):
File "test.py", line 111, in <module>
method1('arg1')
File "test.py", line 88, in newfunc_template
return func(*args, **kwargs)
TypeError: method2() takes exactly 1 argument (2 given)
似乎是在重用对函数的引用？有任何想法吗？
更新：这是 Ned Batchelder 修复的工作代码
def fabric_class_to_function_magic(module_name):
# get the module as an object
module_obj = sys.modules[module_name]
# Iterate over the methods of the class and dynamically create a function
# for each method that calls the method and add it to the current module
for method in inspect.getmembers(TestClass, predicate=inspect.ismethod):
method_name, method_obj = method
# get the bound method
tc = TestClass()
func = getattr(tc, method_name)
# add the function to the current module
setattr(module_obj, method_name, func)
更新2：这是我关于这个主题的博客文章：http: //www.saltycrane.com/blog/2010/09/class-based-fabric-scripts-metaprogramming-hack/