使用Python装饰器分解共享数据验证

我在一个项目类中具有以下两个功能：

def stage_changes(self, change_set_name):
    change_set_id = self._get_change_set_id(change_set_name)
    # Perform validation on change set ID
    self._stage_changes_internal(change_set_id)

def commit_changes(self, change_set_name):
    change_set_id = self._get_change_set_id(change_set_name)
    # Perform validation on change set ID (same validation as first function)
    # Perform some other computation using change set ID
    self._commit_changes_internal(change_set_id, ...)

我希望从这些函数中考虑前两个共享行，即

change_set_id = self._get_change_set_id(change_set_name)
# Perform validation on change set ID

我的问题是:

在这里使用decorator真的有意义吗？或者在我应该只调用一个简单的helper函数的地方，我是不是太有创意了

如果使用装潢师确实有意义，我将如何着手构建它？这样做似乎很麻烦，因为我需要在公共尾声中计算的值来在每个函数中执行额外的计算（即，共享逻辑不仅仅产生副作用，它还返回一个值）

---

正如您提到的，您可以使用辅助函数应用DRY原理。 我认为更多的是关于个人品味，在这里使用助手或装饰功能。 但作为一名装饰师，它可能看起来像这样：

from functools import wraps

def validateData(fn):
    @wraps(fn)
    def wrapper(*args, **kw):
        cls = args[0]
        change_set_name = args[1]

        if change_set_name in ('bar', 'foobar'):
            kw['change_set_id'] = 1
        else:
            kw['change_set_id'] = None

        return fn(*args, **kw)
    return wrapper


class Foo():
    @validateData
    def stage_changes(self, change_set_name, change_set_id=None):
        print('change_set_id in stage_changes:', change_set_id)
        # Perform validation on change set ID
        #self._stage_changes_internal(change_set_id)

    @validateData
    def commit_changes(self, change_set_name, change_set_id=None):
        #change_set_id = self._get_change_set_id(change_set_name)
        print('change_set_id in commit_changes:', change_set_id)
        # Perform validation on change set ID (same validation as first function)
        # Perform some other computation using change set ID
        #self._commit_changes_internal(change_set_id, ...)

f = Foo()
f.stage_changes('bar')
f.stage_changes('banana')

印刷品：

change_set_id in stage_changes: 1
change_set_id in stage_changes: None

---

正如您提到的，您可以使用辅助函数应用DRY原理。 我认为更多的是关于个人品味，在这里使用助手或装饰功能。 但作为一名装饰师，它可能看起来像这样：

from functools import wraps

def validateData(fn):
    @wraps(fn)
    def wrapper(*args, **kw):
        cls = args[0]
        change_set_name = args[1]

        if change_set_name in ('bar', 'foobar'):
            kw['change_set_id'] = 1
        else:
            kw['change_set_id'] = None

        return fn(*args, **kw)
    return wrapper


class Foo():
    @validateData
    def stage_changes(self, change_set_name, change_set_id=None):
        print('change_set_id in stage_changes:', change_set_id)
        # Perform validation on change set ID
        #self._stage_changes_internal(change_set_id)

    @validateData
    def commit_changes(self, change_set_name, change_set_id=None):
        #change_set_id = self._get_change_set_id(change_set_name)
        print('change_set_id in commit_changes:', change_set_id)
        # Perform validation on change set ID (same validation as first function)
        # Perform some other computation using change set ID
        #self._commit_changes_internal(change_set_id, ...)

f = Foo()
f.stage_changes('bar')
f.stage_changes('banana')

印刷品：

change_set_id in stage_changes: 1
change_set_id in stage_changes: None