Question

我尝试阅读有关使用flask-Marshmallow进行序列化的现有问题，但是我似乎无法了解我所想要的东西，我想知道丢失了什么：

我想得到这样的回复：

{
   "data": [ {"name": "Netherlands tour",
    "description": "This is a fascinating tour to take ...",
    "price": 30.0,
    "available_dates":[
        {
            "date": "2018-05-05"
        },
        {
            "date": "2018-07-07"
        }
    ],
    "destinations":[
        {
            "location":"A",
            "tour_type":"Adventure",
            "danger_type":"Low"
        },
        {
             "location":"B",
            "tour_type":"Leisure",
            "danger_type":"Medium"
        }
    ],
    "capacity": 30},
  ...
]
}

但是我没有得到它，只是得到了这个：

{
  "data": [
    {
      "capacity": 30,
      "description": "This is a fascinating tour to take",
      "name": "Europe tour",
      "price": 30.0
    },
    {
      "capacity": 30,
      "description": "This is a fascinating tour to take",
      "name": "Europe tour",
      "price": 30.0
    },
    {
      "capacity": 30,
      "description": "This is a fascinating tour to take",
      "name": "Europe tour",
      "price": 30.0
    },
    {
      "capacity": 30,
      "description": "This is a fascinating tour to take",
      "name": "Europe tour",
      "price": 30.0
    }
]

下面是我的模特：

class TourPackages(db.Model):
    __tablename__ = 'tourpackage'

    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))
    description = db.Column(db.TEXT)
    price = db.Column(db.Float)
    destinations = db.relationship('Destinations', backref='destination_id', lazy='dynamic')
    available_dates = db.relationship('AvailableDates', backref='available_date_id', lazy='dynamic')
    capacity = db.Column(db.Integer)
    created_on = db.Column(db.DateTime(), default=datetime.utcnow)


class Destinations(db.Model):
    __tablename__ = 'destinations'

    id = db.Column(db.Integer, primary_key=True)
    tour_Packages = db.Column(db.Integer, db.ForeignKey('tourpackage.id'))
    location = db.Column(db.String(50))
    tour_type = db.Column(db.String(50))
    danger_type = db.Column(db.String(50))


class AvailableDates(db.Model):
    __tablename__ = 'availabledates'

    id = db.Column(db.Integer, primary_key=True)
    date_available = db.Column(db.String(50))
    tour_date = db.Column(db.Integer, db.ForeignKey('tourpackage.id'))

然后，这是我的棉花糖模式：

class DestinationSchema(ma.Schema):
    class Meta:
        model = Destinations
        sqla_session = Session
        fields = ('id', 'location', 'danger_type')



class AvailableDatesSchema(ma.Schema):
    class Meta:
        model = AvailableDates
        sqla_session = Session
        fields = ('id', 'date_')


class TourPackagesSchema(ma.Schema):
    class Meta:
        model = TourPackages
        fields = ('id', 'name', 'description', 'price', 'capacity')

    destiantion = fields.Nested(DestinationSchema, many=True)
    available = fields.Nested(AvailableDatesSchema, many=True)

然后，在我的GET请求方法中，这是我的代码：

def get_all_tours(self):
    tours = db.session.query(TourPackages.name, TourPackages.description, TourPackages.price,
                             TourPackages.capacity,
                             Destinations.location,
                             Destinations.tour_type,
                             Destinations.danger_type, AvailableDates.date_available).join(
        Destinations).join(AvailableDates).all()


    tour_schema = TourPackagesSchema(many=True)


    dump_data = tour_schema.dump(tours)

    output = jsonify({'data' : dump_data})
    return output

序列化嵌套json响应时我缺少什么？

Answer 1

我希望我的回答会有所帮助。

型号：

from dataclasses import dataclass
from typing import Optional


@dataclass
class Settings:
    verbose: Optional[bool] = None
    detailed: Optional[bool] = None

    def __post_init__(self) -> None:

        args = []
        if self.verbose is None:
            args.append('verbose')

        if self.detailed is None:
            args.append('detailed')

        if args:
            s = f"Settings class could not locate {args} as a setting."
            s += " Skipping..."
            print(s)


@dataclass
class FSettings(Settings):
    vals: Optional[list] = None


args = {'vals': ["a", "b"], 'verbose': True, 'detailed': False}
f_settings = FSettings(**args)

args = {'vals': ["a", "b"]}
f_settings = FSettings(**args)
# Settings class could not locate ['verbose', 'detailed'] as a setting. Skipping..

方案：

class TourPackage(db.Model):
    __tablename__ = 'tour_packages'

    id = db.Column(db.Integer, primary_key=True)
    created_on = db.Column(db.DateTime(), default=datetime.utcnow)
    name = db.Column(db.String(50))
    description = db.Column(db.TEXT)
    price = db.Column(db.Float)
    capacity = db.Column(db.Integer)
    destinations = db.relationship('Destination', backref='tour_package', lazy='dynamic')
    available_dates = db.relationship('AvailableDate', backref='tour_package', lazy='dynamic')

class Destination(db.Model):
    __tablename__ = 'destinations'

    id = db.Column(db.Integer, primary_key=True)
    tour_package_id = db.Column(db.Integer, db.ForeignKey('tour_packages.id'))
    location = db.Column(db.String(50))
    tour_type = db.Column(db.String(50))
    danger_type = db.Column(db.String(50))

class AvailableDate(db.Model):
    __tablename__ = 'available_dates'

    id = db.Column(db.Integer, primary_key=True)
    tour_package_id = db.Column(db.Integer, db.ForeignKey('tour_packages.id'))
    date_available = db.Column(db.String(50))

路线：

class DestinationSchema(ma.SQLAlchemyAutoSchema):
    class Meta:
        model = Destination

class AvailableDateSchema(ma.SQLAlchemyAutoSchema):
    class Meta:
        model = AvailableDate


class TourPackageSchema(ma.SQLAlchemyAutoSchema):
    class Meta:
        model = TourPackage

    destinations = ma.Nested(DestinationSchema, many=True)
    available_dates = ma.Nested(AvailableDateSchema, many=True)

用烧瓶棉花糖序列化一对多关系嵌套json

1 个答案: