python3 中的循环导入

Question

我有一个包含多个文件的包。每个文件都包含一个 class 并且 class 是相互依赖的。如何在不将所有代码放在一个文件中的情况下避免循环依赖。有没有更好的方法来重构代码或者有没有办法解决循环导入

这是目录结构

.
|-- Complainant.py
|-- Complaint.py
`-- __init__.py

Complaint.py:

from .Complainant import Complainant

class Complaint(BaseDocument):
    ALL_STATUS = ["waiting","resolved", "rejected"]
    text = TextField()
    timestamp = DateTimeField()
    status = TextField()
    complainant_id = TextField()
    department_ids = ListField(TextField())

    def get_complainant(self):
        db = DBManager.db()
        complainant = Complainant.load(db, self.complainant_id)
        return complainant

Complainant.py

from .Complaint import Complaint

class Complainant(BaseDocument):
    account_type = TextField()
    account_handle = TextField()
    complaint_ids = ListField(TextField())

    def get_complaints(self):
        db = DBManager.db()
        complaints = [Complaint.load(db, i) for i in self.complaint_ids]
        return complaints

init.py

from .Complaint import Complaint
from .Complainant import Complainant

__all__ = [
    Complaint,
    Complainant
]

Answer 1

在具有循环依赖的系统中，为了避免循环导入，通常必须将相互依赖的部分放在同一个模块中。

在您的情况下，只有一小部分类 Complaint 和 Complainant 是相互依赖的。您可以重构模块，将不相互依赖的部分放入 BaseComplaint.py 和 BaseComplainant.py 中的类，并使用第三个模块定义子类 Complaint和 Complainant.

目录结构：

.
|-- BaseComplainant.py
|-- BaseComplaint.py
|-- ComplaintComplainant.py
`-- __init__.py

BaseComplaint.py:

class BaseComplaint(BaseDocument):
    ALL_STATUS = ["waiting","resolved", "rejected"]
    text = TextField()
    timestamp = DateTimeField()
    status = TextField()
    complainant_id = TextField()
    department_ids = ListField(TextField())

BaseComplainant.py

class BaseComplainant(BaseDocument):
    account_type = TextField()
    account_handle = TextField()
    complaint_ids = ListField(TextField())

ComplaintComplainant.py（也许你能找到更好的名字）

from .BaseComplaint import BaseComplaint
from .BaseComplainant import BaseComplainant

class Complaint(BaseComplaint):
    def get_complainant(self):
        db = DBManager.db()
        complainant = Complainant.load(db, self.complainant_id)
        return complainant

class Complainant(BaseComplainant):
    def get_complaints(self):
        db = DBManager.db()
        complaints = [Complaint.load(db, i) for i in self.complaint_ids]
        return complaints

init.py

from .ComplaintComplainant import Complaint, Complainant

__all__ = [
    Complaint,
    Complainant
]

python3 中的循环导入

Circular imports in python3

circular-dependency

package

python-3.x