如何使用python解决循环导入的问题

Question

我正在学习如何使用flask-restful 和jwt 在python 中创建restful api，现在我遇到了导入问题。这是错误和我的源代码 错误： py .\api.py

回溯（最近一次通话最后一次）： 文件“C:\Users\Amoungui\Documents\Projects\API-playlist-master\api.py”，第 4 行，在 从应用程序导入应用程序，api 文件“C:\Users\Amoungui\Documents\Projects\API-playlist-master\app.py”，第 4 行，在 从安全导入身份验证，身份 文件“C:\Users\Amoungui\Documents\Projects\API-playlist-master\security.py”，第 1 行，在 从用户导入用户 文件“C:\Users\Amoungui\Documents\Projects\API-playlist-master\User.py”，第 1 行，在 从应用程序导入数据库 ImportError：无法从部分初始化的模块“app”导入名称“db”（很可能是由于循环导入）（C:\Users\Amoungui\Documents\Projects\API-playlist-master\app.py）

这是文件代码 index.py：

from flask import request
from flask_restful import Resource
from flask_jwt import jwt_required
from app import app, api
from CustomerRepository import CustomerRepository as Repository

items = Repository.findAll()

class UserController(Resource):
    @jwt_required()
    def get(self, id):
        item = next(filter(lambda x: x['id'] == id, items), None)
        return {'item': item}, 200 if item else 404
    
    def post(self):
        data = request.get_json()
        new_item = {'tel': data['tel'],'password':data['password']}
        items.append(new_item)
        return new_item
    
    def delete(self, id):
        global items
        items = list(filter(lambda x:x['name']!=id,items))
        return items

    def put(self, id):
        data = request.get_json()
        item = next(filter(lambda x:x['id'] == id, items),None)
        if item is None:
            item = {'tel':data['tel'], 'password':data['password']}
            items.append(item)
        else:
            item.update(data)

class ItemList(Resource):
    def get(self):
        return{'item':items}

api.add_resource(UserController,'/items/<string:name>')
api.add_resource(ItemList,'/items')


app.run(port=4000,debug=True)

我拥有所有配置的 app.py

from flask import Flask
from flask_mongoengine import MongoEngine
from flask_restful import Api
from security import auth,identity
from flask_jwt import JWT
import urllib

app = Flask(__name__)

database_name = "API"
mongodb_password = ""
DB_URI = "mongodb+srv://m001-student:"+ urllib.parse.quote(mongodb_password) +"@cluster0.hr17o.mongodb.net/{}?retryWrites=true&w=majority".format(database_name)
app.config['MONGODB_HOST'] = DB_URI

app.secret_key = '#0#'
api = Api(app)
jwt = JWT(app, auth, identity)#/auth

db = MongoEngine()
db.init_app(app)

CustomerRepository.py

from flask import make_response, request, jsonify
from User import User

class CustomerRepository():
    
    def findAll():
        users = []
        for user in User.objects:
            users.append(user)
            
        return make_response(jsonify(users), 200)

用户.py：

from app import db

class User(db.Document):
    customer_id = db.IntField()
    tel = db.StringField()
    password = db.IntField(6)
    
    def to_json(self):
        return {
            "customer_id": self.customer_id,
            "tel": self.tel,
            "password": self.password,
        }

security.py

from User import User
from werkzeug.security import safe_str_cmp

def auth(tel,password):
    user = User.findByName(tel)
    if user and safe_str_cmp(user.password,password):
        return user

def identity(payload):
    id = payload['identity']
    return User.find_by_id(id)

def findByName(number):
    customer_obj = User.objects(tel=number).first()
    if customer_obj:
        return customer_obj

def findById(customer_id):
    customer_obj = User.objects(customer_id=customer_id).first()
    if customer_obj:
        return customer_obj

提前感谢您的帮助

Answer 1

我可以看到您在index.py 中有api.add_resource(UserController,'/items/<string:name>')。但我没有看到 api 被定义或从任何地方导入。你可以从那里开始。

Answer 2

我尝试了一种新方法，效果很好 应用程序.py

from flask import Flask

app = Flask(__name__)

index.py

from flask import Flask, jsonify, request
from flask_restful import Resource
from Customer import Customer

class HelloWorld(Resource): 

    def get(self):
        return Customer.findAll(Customer)
    
    def post(self):
        data = request.get_json()
        
        customer = Customer(
                    tel=data['tel'], 
                    password=data['password']
                )
        customer.save()     
    
class Multi(Resource):
    def get(self, num):
        return {'result': num*10}

客户.py

from flask import jsonify, make_response
from mongoose import db

class Customer(db.Document):
    customer_id = db.IntField()
    tel = db.StringField()
    password = db.IntField(6)
    
    def to_json(self):
        return {
            "customer_id": self.customer_id,
            "tel": self.tel,
            "password": self.password,
        }

    def findAll(self):
        users = []
        for user in self.objects:
            users.append(user)
            
        return make_response(jsonify(users), 200)

routes.py

from index import HelloWorld, Multi
from flask_restful import Api
from app import app
api = Api(app)

api.add_resource(HelloWorld, '/')
api.add_resource(Multi, '/multi/<int:num>')

if __name__ == '__main__':
    app.run(debug=True)

猫鼬.py

from flask_mongoengine import MongoEngine
from app import app
import urllib

database_name = "API"
mongodb_password = ""
DB_URI = "mongodb+srv://m001-student:"+ urllib.parse.quote(mongodb_password) +"@cluster0.hr17o.mongodb.net/{}?retryWrites=true&w=majority".format(database_name)
app.config['MONGODB_HOST'] = DB_URI


db = MongoEngine()
db.init_app(app)