在 Query.Get 上获取 TypeError“意外的关键字参数”

Question

我正在关注这个 Flask Mega-Tutorial，但在某种程度上遇到了问题。我正在使用 PyCharm CE for Windows。

我遇到问题的部分是在将用户注册表单添加到应用程序之后。运行应用程序并尝试在浏览器中注册新用户时，我从表单验证中收到以下错误：

File "C:\Users\janmar\OneDrive - KONGSBERG MARITIME AS\Programming\Python\Projects\colligero\app\forms.py", line 49, in validate_username
user = User.query.get(username=username.data).first()
TypeError: get() got an unexpected keyword argument 'username'

这来自 forms.py 模块中的自定义验证方法“def validate_username”。我猜它无法在 models.py 模块的 User 类中“找到”“用户名”项？

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


class LoginForm(FlaskForm):

    username = StringField("Username", validators=[DataRequired()])
    password = PasswordField("Password", validators=[DataRequired()])
    remember_me = BooleanField("Remember Me")
    submit = SubmitField("Sign In")


class RegistrationForm(FlaskForm):

    first_name = StringField("First Name", validators=[
        Regexp(regex=r'^[a-zA-Z]+$', message="First name can not contain numbers or special characters.")])
    last_name = StringField("Last Name", validators=[
        Regexp(regex=r'^[a-zA-Z]+$', message="First name can not contain numbers or special characters.")])
    username = StringField("Username", validators=[
        Regexp(regex=r'^\w+$', message="Username can only contain letters, numbers or underscore."),
        Length(min=5, max=25, message="Username must be between 5 and 25 characters.")])
    email = StringField("Email", validators=[
        DataRequired(),
        Email()])
    password = PasswordField("Password", validators=[
        DataRequired()])
    confirm = PasswordField("Repeat Password", validators=[
        DataRequired(), EqualTo('password')])
    submit = SubmitField("Register")

    def validate_username(self, username):

        user = User.query.get(username=username.data).first()

        if user is not None:

            raise ValidationError("Username is already taken by another. Please select a different username.")

    def validate_email(self, email):

        user = User.query.get(email=email.data).first()

        if user is not None:

            raise ValidationError("Email is already taken by another user. Please select a different email.")

这是models.py文件的内容。

from datetime import datetime
from werkzeug.security import generate_password_hash, check_password_hash
from flask_login import UserMixin
from app import db, login


class User(UserMixin, db.Model):

    id = db.Column(db.Integer, primary_key=True)
    first_name = db.Column(db.String(32), index=True)
    last_name = db.Column(db.String(32), index=True)
    username = db.Column(db.String(64), index=True, unique=True)
    email = db.Column(db.String(120), index=True, unique=True)
    password_hash = db.Column(db.String(128))
    posts = db.relationship('Post', backref='author', lazy='dynamic')

    def set_password(self, password):

        self.password_hash = generate_password_hash(password)

    def check_password(self, password):

        return check_password_hash(self.password_hash, password)

    def __repr__(self):

        return "<User {}>".format(self.username)


@login.user_loader
def load_user(id):

    return User.query.get(int(id))

我已经尝试从终端会话中以相同的方式查询用户表，它似乎工作正常，所以我不知道是什么导致了这里的问题。此外，PyCharm 编辑器似乎对两种验证方法 'validate_username' 和 'validate_email' 发出警告，称这些方法“可能是'静态'”。这与我遇到的错误有什么关系吗？

Answer 1

我认为您在此处将语法与 Django 混淆了。在 Flask-SQLAlchemy 中，get 不接受关键字参数 - 它仅用于通过 PK 进行的查询，正如您在 load_user 中所做的那样。您需要使用filter。

user = User.query.filter(username=username.data).first()