将太多的参数传递给构造函数是否被视为反模式? [英] Is passing too many arguments to the constructor considered an anti-pattern?

问题描述

我正在考虑使用factory_boy库进行API测试.文档中的一个示例是:

I am considering using the factory_boy library for API testing. An example from the documentation is:

class UserFactory(factory.Factory):
    class Meta:
        model = base.User

    first_name = "John"
    last_name = "Doe"

为此，我们需要将first_name，last_name等作为参数传递给base.User() class的__init__()方法.但是，如果您有很多参数，则结果如下:

For this to work, we need first_name, last_name, etc to be passed as parameters to the __init__() method of the base.User() class. However, if you have many parameters this leads to something like:

class User(object):

    GENDER_MALE = 'mr'
    GENDER_FEMALE = 'ms'

    def __init__(self, title=None, first_name=None, last_name=None, is_guest=None,
             company_name=None, mobile=None, landline=None, email=None, password=None,
             fax=None, wants_sms_notification=None, wants_email_notification=None,
             wants_newsletter=None, street_address=None):

        self. title = title
        self.first_name = first_name
        self.last_name = last_name
        self.company_name = company_name
        self.mobile = mobile
        self.landline = landline
        self.email = email
        self.password = password
        self.fax = fax
        self.is_guest = is_guest
        self.wants_sms_notification = wants_sms_notification
        self.wants_email_notification = wants_email_notification
        self.wants_newsletter = wants_newsletter
        self.company_name = company_name
        self.street_address = street_address

现在的问题是，这种构造是否被认为是反模式的?如果是的话，我还有什么选择?

Now the question is, is this construction considered anti-pattern, and if yes, what alternatives do I have?

谢谢

推荐答案

您可以将__init__方法的关键字参数打包到一个字典中，并使用setattr动态设置它们:

You could pack the __init__ method's keyword arguments into one dict, and set them dynamically with setattr:

class User(object):
    GENDER_MALE = 'mr'
    GENDER_FEMALE = 'ms'
    def __init__(self, **kwargs):
        valid_keys = ["title", "first_name", "last_name", "is_guest", "company_name", "mobile", "landline", "email", "password", "fax", "wants_sms_notification", "wants_email_notification", "wants_newsletter","street_address"]
        for key in valid_keys:
            setattr(self, key, kwargs.get(key))

x = User(first_name="Kevin", password="hunter2")
print(x.first_name, x.password, x.mobile)

但是，这样做的缺点是不允许您在不命名的情况下提供参数-x = User("Mr", "Kevin")适用于您的原始代码，但不适用于此代码.

However, this has the drawback of disallowing you from supplying arguments without naming them - x = User("Mr", "Kevin") works with your original code, but not with this code.

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