Python 烧瓶-我可以'；t从flask_应用程序导入用户模型

当我尝试在flask_应用程序（包含应用程序）中导入“用户”模型时，我收到一个错误，我收到ImportError:无法从“模型”错误导入名称“用户”

forms.py-我正在尝试从flask_应用程序导入用户

from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, SubmitField, BooleanField
from wtforms.validators import DataRequired, Length, Email, EqualTo, ValidationError
from flask_app import User


class RegistrationForm(FlaskForm):
    username = StringField('Username',
                           validators=[DataRequired(), Length(min=2, max=20)])
    email = StringField('Email',
                        validators=[DataRequired(), Email()])
    password = PasswordField('Password', validators=[DataRequired()])
    confirm_password = PasswordField('Confirm Password',
                                     validators=[DataRequired(), EqualTo('password')])
    submit = SubmitField('Sign Up')

    def validate_username(self, username):
        user = User.query.filter_by(username=username.data).first()
        if user:
            raise ValidationError('That username is taken. Please choose a different one.')

    def validate_email(self, email):
        user = User.query.filter_by(email=email.data).first()
        if user:
            raise ValidationError('That email is taken. Please choose a different one.')

以下是用户模型：

from datetime import datetime
from flask import Flask, render_template, url_for, flash, redirect
from flask_sqlalchemy import SQLAlchemy
from forms import RegistrationForm, LoginForm
from flask_bcrypt import Bcrypt
from flask_login import login_user, current_user, logout_user, login_required, LoginManager

app = Flask(__name__)
app.config['SECRET_KEY'] = ''
app.config['SQLALCHEMY_DATABASE_URI'] = ''
db = SQLAlchemy(app)
bcrypt = Bcrypt(app)
login_manager = LoginManager(app)
login_manager.login_view = 'login'
login_manager.login_message_category = 'info'


class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(20), unique=True, nullable=False)
    email = db.Column(db.String(120), unique=True, nullable=False)
    image_file = db.Column(db.String(20), nullable=False, default='default.jpg')
    password = db.Column(db.String(60), nullable=False)
    posts = db.relationship('Post', backref='author', lazy=True)

    def __repr__(self):
        return f"User('{self.username}', '{self.email}', '{self.image_file}')"


@app.route("/")
@app.route("/home")
def home():
    return render_template('home.html', posts=posts)


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

给我这个：

2020-01-12 08:58:53,282: Error running WSGI application
2020-01-12 08:58:53,284: ImportError: cannot import name 'User' from 'models' (/home/kickie/mysite/models.py)
2020-01-12 08:58:53,287:   File "/var/www/fdfdfd_pythonanywhere_com_wsgi.py", line 16, in <module>
2020-01-12 08:58:53,289:     from flask_app import app as application  # noqa
2020-01-12 08:58:53,290: 
2020-01-12 08:58:53,291:   File "/home/kickie/mysite/flask_app.py", line 4, in <module>
2020-01-12 08:58:53,292:     from forms import RegistrationForm, LoginForm
2020-01-12 08:58:53,292: 
2020-01-12 08:58:53,293:   File "/home/kickie/mysite/forms.py", line 4, in <module>
2020-01-12 08:58:53,293:     from flask_app import User

2020-01-12 08:58:53282:运行WSGI应用程序时出错
2020-01-12 08:58:53284:导入错误：无法从“模型”导入名称“用户”（/home/kickie/mysite/models.py）
2020-01-12 08:58:53287：文件“/var/www/fdfdfd_pythonanwhere_com_wsgi.py”，第16行，在
2020-01-12 08:58:53289：来自flask_应用程序导入应用程序作为应用程序#noqa
2020-01-12 08:58:53,290: 
2020-01-12 08:58:53291：文件“/home/kickie/mysite/flask_app.py”，第4行，在
2020-01-12 08:58:53292：从表单导入注册表单，登录信息表单
2020-01-12 08:58:53,292: 
2020-01-12 08:58:53293：文件“/home/kickie/mysite/forms.py”，第4行，在
2020-01-12 08:58:53293：来自flask_应用程序导入用户

---

我收到一个错误，因为应用程序在这里？我是否应该将用户移动到其他位置？

发生这种情况是因为您正在执行

循环导入

# inside flask_app.py
from forms import RegistrationForm

及

---

简单解 为了避免代码中出现此问题，如果您决定使用此结构

1） 只需从flask_应用程序导入用户的

表单.py中删除

2） 在使用模型的方法中导入它

from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, SubmitField, BooleanField
from wtforms.validators import DataRequired, Length, Email, EqualTo, ValidationError
# REMOVE THE IMPORT


class RegistrationForm(FlaskForm):
    username = StringField('Username',
                           validators=[DataRequired(), Length(min=2, max=20)])
    email = StringField('Email',
                        validators=[DataRequired(), Email()])
    password = PasswordField('Password', validators=[DataRequired()])
    confirm_password = PasswordField('Confirm Password',
                                     validators=[DataRequired(), EqualTo('password')])
    submit = SubmitField('Sign Up')

    def validate_username(self, username):
        # Import them inside the methods that are using the Model
        from flask_app import User
        user = User.query.filter_by(username=username.data).first()
        if user:
            raise ValidationError('That username is taken. Please choose a different one.')

    def validate_email(self, email):
        # Import them inside the methods that are using the Model
        from flask_app import User
        user = User.query.filter_by(email=email.data).first()
        if user:
            raise ValidationError('That email is taken. Please choose a different one.')

from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, SubmitField, BooleanField
from wtforms.validators import DataRequired, Length, Email, EqualTo, ValidationError
# REMOVE THE IMPORT


class RegistrationForm(FlaskForm):
    username = StringField('Username',
                           validators=[DataRequired(), Length(min=2, max=20)])
    email = StringField('Email',
                        validators=[DataRequired(), Email()])
    password = PasswordField('Password', validators=[DataRequired()])
    confirm_password = PasswordField('Confirm Password',
                                     validators=[DataRequired(), EqualTo('password')])
    submit = SubmitField('Sign Up')

    def validate_username(self, username):
        # Import them inside the methods that are using the Model
        from flask_app import User
        user = User.query.filter_by(username=username.data).first()
        if user:
            raise ValidationError('That username is taken. Please choose a different one.')

    def validate_email(self, email):
        # Import them inside the methods that are using the Model
        from flask_app import User
        user = User.query.filter_by(email=email.data).first()
        if user:
            raise ValidationError('That email is taken. Please choose a different one.')