python - Flask_Marshmallow 的 Flask sqlAlchemy 验证问题

Question

使用 flask_marshmallow 进行输入验证，使用 scheme.load() ，我无法捕获模型中 @validates 装饰器生成的错误

我在资源中捕获了结果和错误，但错误直接发送给用户

==========model.py==========

```python

from sqlalchemy.orm import validates

from sqlalchemy import Column, ForeignKey, Integer, String, DateTime
from sqlalchemy.orm import relationship, backref
from sqlalchemy import create_engine
from sqlalchemy.sql import func

from flask_marshmallow import Marshmallow
from flask_sqlalchemy import SQLAlchemy
from datetime import datetime
from sqlalchemy.orm import joinedload


db = SQLAlchemy()
ma = Marshmallow()

class Company(db.Model):

    __tablename__ = "company"

    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(250), nullable=False)
    addressLine1 = db.Column(db.String(250), nullable=False)
    addressLine2 = db.Column(db.String(250), nullable=True)
    city = db.Column(db.String(250), nullable=False)
    state = db.Column(db.String(250), nullable=False)
    zipCode = db.Column(db.String(10), nullable=False)
    logo = db.Column(db.String(250), nullable=True)
    website = db.Column(db.String(250), nullable=False)
    recognition = db.Column(db.String(250), nullable=True)
    vision = db.Column(db.String(250), nullable=True)
    history = db.Column(db.String(250), nullable=True)
    mission = db.Column(db.String(250), nullable=True)
    jobs = relationship("Job", cascade="all, delete-orphan")

    def save_to_db(self):
        db.session.add(self)
        db.session.commit()

    @validates('name')
    def validate_name(self, key, name):
        print("=====inside validate_name=======")
        if not name:
            raise AssertionError('No Company name provided')

        if Company.query.filter(Company.name == name).first():
            raise AssertionError('Company name is already in use')

        if len(name) < 4 or len(name) > 120:
            raise AssertionError('Company  name must be between 3 and 120 characters')

        return name

```

==========schemas_company.py==============

```python
from ma import ma
from models.model import Company


class CompanySchema(ma.ModelSchema):

    class Meta:
        model = Company
```

=============resources_company.py

```python
from schemas.company import CompanySchema
company_schema = CompanySchema(exclude='jobs')


COMPANY_ALREADY_EXIST = "A company with the same name already exists"
COMPANY_CREATED_SUCCESSFULLY = "The company was sucessfully created"


@api.route('/company')
class Company(Resource):

    def post(self, *args, **kwargs):
        """ Creating a new Company """
        data = request.get_json(force=True)
        schema = CompanySchema()
        if data:
            logger.info("Data got by /api/test/testId methd %s" % data)


            # Validation with schema.load() OPTION_2
            company, errors = schema.load(data)
            print(company)
            print(errors)

            if errors:
                return {"errors": errors}, 422
            company.save_to_db()
            return {"message": COMPANY_CREATED_SUCCESSFULLY}, 201

```

===========请求==========

这是来自用户的POST请求

{
    "name": "123",
    "addressLine1": "400 S Royal King Ave",
    "addressLine2": "Suite 356",
    "city": "Miami",
    "state": "FL",
    "zipCode": "88377",
    "logo": "This is the logo",
    "website": "http://www.python.com",
    "recognition": "Most innovated company in the USA 2018-2019",
    "vision": "We want to change for better all that needs to be changed",
    "history": "Created in 2016 with the objective of automate all needed process",
    "mission": " Our mission is to find solutions to old problems"
}

====问题描述======

上面的 POST 请求根据 model.py 中的 validate_name 函数生成一个 AssertionError 异常，如下所示:

File "code/models/model.py", line 95, in validate_name
raise AssertionError('Company  name must be between 3 and 120 characters')
AssertionError: Company  name must be between 3 and 120 characters
127.0.0.1 - - [30/Dec/2018 13:44:58] "POST /api/company HTTP/1.1" 500 -

所以返回给用户的响应就是这个无用的错误信息

{
    "message": "Internal Server Error"
}

我的问题是:

我必须做什么才能将引发的 AssertionError 消息发送给用户，而不是这个难看的错误消息？

AssertionError message
{
   "message": "Company  name must be between 3 and 120 characters" 
}

Exception 
{
    "message": "Internal Server Error"
}

我以为错误会捕获@validates('name') 生成的异常，但看起来并非如此。

Answer 1

我找到了解决问题的办法。我更改了架构如下:

from ma import ma
from models.model import Company

from marshmallow import fields, validate


class CompanySchema(ma.ModelSchema):

    name = fields.Str(required=True, validate=[validate.Length(min=4, max=250)])
    addressLine1 = fields.Str(required=True, validate=[validate.Length(min=5, max=250)])
    addressLine2 = fields.Str(required=False, validate=[validate.Length(max=250)])
    city = fields.Str(required=True, validate=[validate.Length(min=5, max=100)])
    state = fields.Str(required=True, validate=[validate.Length(min=2, max=10)])
    zipCode = fields.Str(required=True, validate=[validate.Length(min=5, max=250)])
    logo = fields.Str(required=False, validate=[validate.Length(max=250)])
    website = fields.Str(required=True, validate=[validate.Length(min=5, max=250)])
    recognition = fields.Str(required=False, validate=[validate.Length(max=250)])
    vision = fields.Str(required=False, validate=[validate.Length(max=250)])
    history = fields.Str(required=False, validate=[validate.Length(max=250)])
    mission = fields.Str(required=False, validate=[validate.Length(max=250)])

    class Meta:
        model = Company

现在我不验证模型中的任何内容，所以我的模型只是

class Company(db.Model):

    __tablename__ = "company"

    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(250), nullable=False)
    addressLine1 = db.Column(db.String(250), nullable=False)
    addressLine2 = db.Column(db.String(250), nullable=True)
    city = db.Column(db.String(250), nullable=False)
    state = db.Column(db.String(250), nullable=False)
    zipCode = db.Column(db.String(10), nullable=False)
    logo = db.Column(db.String(250), nullable=True)
    website = db.Column(db.String(250), nullable=False)
    recognition = db.Column(db.String(250), nullable=True)
    vision = db.Column(db.String(250), nullable=True)
    history = db.Column(db.String(250), nullable=True)
    mission = db.Column(db.String(250), nullable=True)
    jobs = relationship("Job", cascade="all, delete-orphan")

    def save_to_db(self):
        print("=====inside save_to_db=======")
        db.session.add(self)
        db.session.commit()

所以在资源( View )端点中，我有:

@api.route('/company')
class Company(Resource):

    def post(self, *args, **kwargs):
        """ Creating a new Company """
        data = request.get_json(force=True)
        schema = CompanySchema()
        if data:
            logger.info("Data got by /api/test/testId method %s" % data)

            # Validation with schema.load() OPTION_2
            company, errors = schema.load(data)
            print(company)

            if errors:
                return {"errors": errors}, 422

            company.save_to_db()
            return {"message": COMPANY_CREATED_SUCCESSFULLY}, 201

因此，现在当用户使用少于 4 个字符的名称发出错误请求时，我能够向用户返回一个漂亮的错误响应，如下所示

{
    "errors": {
        "name": [
            "Length must be between 4 and 250."
        ]
    }
}

但是如果您注意到我这样做的原因以及我使用的“模式”，您将看到以下详细信息

1. -使用 flask_marshmallow 进行序列化和反序列化。
2. -在我的模型中，我使用棉花糖(不是 flask_marshmallow)进行验证
3. -验证与 schema.load() 一起工作
4. -我想知道如何才能向输入添加比我使用的验证更复杂的验证？
5. -这是一个值得遵循的好模式吗，可以做哪些改进？

谢谢