GAE和Flask：在__init__文件中导入模型时引发DuplicatePropertyError

Question

我正在使用GAE Python 2.7标准环境创建基于Flask的Web应用程序。当我尝试在application / __ init__py文件和其他文件中导入动物模型时，App Engine SDK引发DuplicatePropertyError。

DuplicatePropertyError: Class AnimalKind already has property animal_set

.
├── README.md
├── requirements.txt
├── src
│   ├── app.yaml
│   ├── application
│   │   ├── __init__.py
│   │   ├── animal_bp
│   │   │   ├── __init__.py
│   │   │   └── views.py
│   │   ├── appengine_config.py
│   │   ├── main.py
│   │   ├── models
│   │   │   ├── __init__.py
│   │   │   ├── base_models.py
│   │   │   ├── common_models.py
│   │   │   └── kind_models.py
│   │   └── settings.py
│   ├── index.yaml
│   ├── lib

app.yaml

service: default
runtime: python27
api_version: 1
threadsafe: true
instance_class: F1

builtins:
- appstats: on
- remote_api: on

libraries:
- name: ssl
  version: latest

inbound_services:
- warmup

# [START handlers]
handlers:
- url: /static
  static_dir: static

- url: .*
  script: run.application.app
  # script: main.app
  secure: always
# [END handlers]

run.py

# -*- coding: utf-8 -*-
import os
import sys

sys.path.insert(1, os.path.join(os.path.abspath('.'), 'lib'))
sys.path.insert(1, os.path.join(os.path.abspath('.'), 'application'))

import application

application / init。py

# -*- coding: utf-8 -*-
import os

from flask import Flask, g, request, session
from werkzeug.debug import DebuggedApplication
from animal_bp.views import animal_bp
from models.common_models import Animal


def create_app():
    app = Flask(__name__)
    app.config.from_object('application.settings.Local')
    app.wsgi_app = DebuggedApplication(app.wsgi_app, evalex=True)
    app.register_blueprint(animal_bp)
    return app

app = create_app()

application / models / common_models.py

from google.appengine.ext import db
from models.kind_models import AnimalKind


class Animal(db.Model):
    """
    Animal Model
    """
    animal_kind_name = db.ReferenceProperty(AnimalKind)

application / models / kind_models.py

from google.appengine.ext import db


class AnimalKind(db.Model):
    """
    Kind Model
    """
    name = db.StringProperty(required=True)

application / animal_bp / views.py

from flask import Blueprint
from models.common_models import Animal

animal_bp = Blueprint('animal_bp', __name__)


@animal_bp.route('/')
def hello():
    return 'Hello world1'

例如，如果我删除animal_bp / views.py中的“从models.common_models导入动物”。错误不会出现。当然，当我从application / init。py文件中删除“ from models.common_models import Animal”时，不会引发错误。

我没有任何重复属性，但是由于我的目录结构，初始化过程可能运行了两次。抱歉，这么长的问题，但是任何帮助都将受到欢迎！

我正在使用GAE Python 2.7标准环境创建基于Flask的Web应用程序。当我尝试将动物模型导入application / __ init__py文件和其他文件中时，App Engine SDK会引发...

Answer 1

from google.appengine.ext import db
from models.kind_models import AnimalKind


class Animal(db.Model):
    """
    Animal Model
    """
    animal_kind_name = db.ReferenceProperty(AnimalKind)