Getting "werkzeug.exceptions.BadRequestKeyError: 400 Bad Request" Upon Creating Form on Python Flask REST API

Question

我正在学习 Python Flask 并学习这门课程，它教我用它构建 RESTful API。

现在，我正在尝试使用 request.form 通过其“/register”路由向用户请求信息（提交），但是在使用 Postman 测试其 POST 请求时我得到 raise exceptions.BadRequestKeyError(key) werkzeug.exceptions.BadRequestKeyError: 400 Bad Request: 浏览器（或代理）发送了该服务器无法理解的请求。键错误：'email'.

Error as depicted in Postman POST Request as shown in Postman

我在这里查看了其他看起来有类似问题的帖子，但其中一些也包含 HTML（令人困惑！）或者所提出的解决方案似乎建议使用 .get()，我已经尝试过但是虽然它可以防止 400 发生，但它会绕过任何表单填写（这不是我想要的）。

相关路线如下：

@app.route('/register', methods=['POST'])
def register():
    email = request.form['email']
    test = User.query.filter_by(email=email).first()
    if test:
        return jsonify(message='That email already exists.'), 409
    else:
        first_name = request.form['first_name']
        last_name = request.form['last_name']
        password = request.form['password']
        user = User(first_name=first_name, last_name=last_name, email=email, password=password)
        db.session.add(user)
        db.session.commit()
        return jsonify(message="User created successfully."), 201

以下是此文件中到目前为止使用的所有代码；称为 'app.py'（也有 SQLAlchemy、OS、Flask Marshmallow）：

from flask import Flask, jsonify, request
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import Column, Integer, String, Float
import os
from flask_marshmallow import Marshmallow


app = Flask(__name__)
basedir = os.path.abspath(os.path.dirname(__file__))
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' + os.path.join(basedir, 'planets.db')


db = SQLAlchemy(app)
ma = Marshmallow(app)


@app.cli.command('db_create')
def db_create():
    db.create_all()
    print('Database created!')


@app.cli.command('db_drop')
def db_drop():
    db.drop_all()
    print('Database dropped!')


@app.cli.command('db_seed')
def db_seed():
    mercury = Planet(planet_name='Mercury',
                     planet_type='Class D',
                     home_star='Sol',
                     mass=2.258e23,
                     radius=1516,
                     distance=35.98e6)

    venus = Planet(planet_name='Venus',
                         planet_type='Class K',
                         home_star='Sol',
                         mass=4.867e24,
                         radius=3760,
                         distance=67.24e6)

    earth = Planet(planet_name='Earth',
                     planet_type='Class M',
                     home_star='Sol',
                     mass=5.972e24,
                     radius=3959,
                     distance=92.96e6)

    db.session.add(mercury)
    db.session.add(venus)
    db.session.add(earth)

    test_user = User(first_name='William',
                     last_name='Herschel',
                     email='test@test.com',
                     password='P@ssw0rd')

    db.session.add(test_user)
    db.session.commit()
    print('Database seeded!')


@app.route('/')
def hello_world():
    return 'Hello World!'


@app.route('/super_simple')
def super_simple():
    return jsonify(message='Hello from the Planetary API.'), 200


@app.route('/not_found')
def not_found():
    return jsonify(message='That resource was not found'), 404


@app.route('/parameters')
def parameters():
    name = request.args.get('name')
    age = int(request.args.get('age'))
    if age < 18:
        return jsonify(message="Sorry " + name + ", you are not old enough."), 401
    else:
        return jsonify(message="Welcome " + name + ", you are old enough!")


@app.route('/url_variables/<string:name>/<int:age>')
def url_variables(name: str, age: int):
    if age < 18:
        return jsonify(message="Sorry " + name + ", you are not old enough."), 401
    else:
        return jsonify(message="Welcome " + name + ", you are old enough!")


@app.route('/planets', methods=['GET'])
def planets():
    planets_list = Planet.query.all()
    result = planets_schema.dump(planets_list)
    return jsonify(result.data)


@app.route('/register', methods=['POST'])
def register():
    email = request.form['email']
    test = User.query.filter_by(email=email).first()
    if test:
        return jsonify(message='That email already exists.'), 409
    else:
        first_name = request.form['first_name']
        last_name = request.form['last_name']
        password = request.form['password']
        user = User(first_name=first_name, last_name=last_name, email=email, password=password)
        db.session.add(user)
        db.session.commit()
        return jsonify(message="User created successfully."), 201


# database models
class User(db.Model):
    __tablename__ = 'users'
    id = Column(Integer, primary_key=True)
    first_name = Column(String)
    last_name = Column(String)
    email = Column(String, unique=True)
    password = Column(String)


class Planet(db.Model):
    __tablename__ = 'planets'
    planet_id = Column(Integer, primary_key=True)
    planet_name = Column(String)
    planet_type = Column(String)
    home_star = Column(String)
    mass = Column(Float)
    radius = Column(Float)
    distance = Column(Float)

class UserSchema(ma.Schema):
    class Meta:
        fields = ('id', 'first_name', 'last_name', 'email', 'password')


class PlanetSchema(ma.Schema):
    class Meta:
        fields = ('planet_id', 'planet_name', 'planet_type', 'home_star', 'mass', 'radius', 'distance')


user_schema = UserSchema()
users_schema = UserSchema(many=True)

planet_schema = PlanetSchema()
planets_schema = PlanetSchema(many=True)


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

任何关于为什么会发生此错误的见解，以及我如何在仍然允许用户输入电子邮件、first_name 等字段的同时修复它，将不胜感激！

提前致谢。

Answer 1

如果您尝试访问请求中的对象或字段，而客户端尚未在请求中发送字段，则会引发 BadRequest 错误。

看来您在邮递员请求中输入错误。还要确保像这样访问它request.form['']

Getting "werkzeug.exceptions.BadRequestKeyError: 400 Bad Request" Upon Creating Form on Python Flask REST API

Getting "werkzeug.exceptions.BadRequestKeyError: 400 Bad Request" Upon Creating Form on Python Flask REST API

rest

post

flask

http-status-code-400

marshmallow