10

Marshmallow を使用して SQLAlchemy オブジェクトの逆シリアル化とシリアル化を実行しようとしていますが、ORM で地理フィールドを処理するときに問題が発生します。

まずモデル：

class Address(db.Model, TableColumnsBase):
    __tablename__ = 'address'
    addressLine1 = db.Column(String(255), nullable=True, info="Street address, company name, c/o")
    addressLine2 = db.Column(String(255), nullable=True, info="Apartment, suite, unit, building floor, etc")
    countryCode = db.Column(String(255), nullable=True, info="Country code such as AU, US etc")
    suburb = db.Column(String(255), nullable=True, info="Users suburb such as Elizabeth Bay")
    postcode = db.Column(String(32), nullable=True, info="Users postcode such as 2011 for Elizabeth Bay")
    state = db.Column(String(64), info="State for user such as NSW")
    user_presence = one_to_many('UserPresence', backref = 'user', lazy='select', cascade='all, delete-orphan')

    location = Column(Geography(geometry_type='POINT', srid=4326))
    discriminator = Column('type', String(50))
    __mapper_args__ = {'polymorphic_on': discriminator}

    def as_physical(self):
        pa = {   # TODO - stub, make it proper
            "latitude": 2.1,
            "longitude": 1.1,
            "unitNumber": '1',
            "streetNumber": self.addressLine1,
            "streetName": self.addressLine2,
            "streetType": 'street',
            "suburb": self.suburb,
            "postcode": self.postcode
        }
        return pa

次に、マシュマロ スキーマ:

class AddressSchema(ModelSchema):
    class Meta:
        model = Address
        sqla_session

次に、実行しようとしたときのエラー:

/Users/james/.virtualenvs/trustmile-api-p2710/bin/python /Users/james/Documents/workspace/trustmile-backend/trustmile/tests/postgis_scratch.py
Traceback (most recent call last):
  File "/Users/james/Documents/workspace/trustmile-backend/trustmile/tests/postgis_scratch.py", line 1, in <module>
    from app import db
  File "/Users/james/Documents/workspace/trustmile-backend/trustmile/app/__init__.py", line 54, in <module>
    from app.api.consumer_v1 import bp as blueprint
  File "/Users/james/Documents/workspace/trustmile-backend/trustmile/app/api/__init__.py", line 4, in <module>
    import courier_v1
  File "/Users/james/Documents/workspace/trustmile-backend/trustmile/app/api/courier_v1/__init__.py", line 5, in <module>
    from .routes import routes
  File "/Users/james/Documents/workspace/trustmile-backend/trustmile/app/api/courier_v1/routes.py", line 10, in <module>
    from .api.nearestNeighbours_latitude_longitude import NearestneighboursLatitudeLongitude
  File "/Users/james/Documents/workspace/trustmile-backend/trustmile/app/api/courier_v1/api/__init__.py", line 5, in <module>
    from app.ops import requesthandler
  File "/Users/james/Documents/workspace/trustmile-backend/trustmile/app/ops/requesthandler.py", line 1, in <module>
    from app.ops.consumer_operations import cons_ops, ConsumerOperationsFactory
  File "/Users/james/Documents/workspace/trustmile-backend/trustmile/app/ops/consumer_operations.py", line 19, in <module>
    from app.users.serialize import ApplicationInstallationSchema, UserAddressSchema, ConsumerUserSchema, CourierUserSchema
  File "/Users/james/Documents/workspace/trustmile-backend/trustmile/app/users/serialize.py", line 40, in <module>
    class AddressSchema(ModelSchema):
  File "/Users/james/.virtualenvs/trustmile-api-p2710/lib/python2.7/site-packages/marshmallow/schema.py", line 116, in __new__
    dict_cls=dict_cls
  File "/Users/james/.virtualenvs/trustmile-api-p2710/lib/python2.7/site-packages/marshmallow_sqlalchemy/schema.py", line 57, in get_declared_fields
    declared_fields = mcs.get_fields(converter, opts)
  File "/Users/james/.virtualenvs/trustmile-api-p2710/lib/python2.7/site-packages/marshmallow_sqlalchemy/schema.py", line 90, in get_fields
    include_fk=opts.include_fk,
  File "/Users/james/.virtualenvs/trustmile-api-p2710/lib/python2.7/site-packages/marshmallow_sqlalchemy/convert.py", line 77, in fields_for_model
    field = self.property2field(prop)
  File "/Users/james/.virtualenvs/trustmile-api-p2710/lib/python2.7/site-packages/marshmallow_sqlalchemy/convert.py", line 95, in property2field
    field_class = self._get_field_class_for_property(prop)
  File "/Users/james/.virtualenvs/trustmile-api-p2710/lib/python2.7/site-packages/marshmallow_sqlalchemy/convert.py", line 153, in _get_field_class_for_property
    field_cls = self._get_field_class_for_column(column)
  File "/Users/james/.virtualenvs/trustmile-api-p2710/lib/python2.7/site-packages/marshmallow_sqlalchemy/convert.py", line 123, in _get_field_class_for_column
    return self._get_field_class_for_data_type(column.type)
  File "/Users/james/.virtualenvs/trustmile-api-p2710/lib/python2.7/site-packages/marshmallow_sqlalchemy/convert.py", line 145, in _get_field_class_for_data_type
    'Could not find field column of type {0}.'.format(types[0]))
marshmallow_sqlalchemy.exceptions.ModelConversionError: Could not find field column of type <class 'geoalchemy2.types.Geography'>.

場所フィールドでいくつかのオーバーライドを試みましたが、役に立ちませんでした。どんな助けでも大歓迎です。

2016 年 1 月 24 日更新

これは、より単純なモデルを使用した瞬間としての私のコードです。

SQLAlchemyModel:

class Location(db.Model, TableColumnsBase):
    __tablename__ = "location"
    loc = db.Column(Geography(geometry_type='POINT', srid=4326))

marshmallow_sqlalchemy スキーマ オブジェクト

class LocationSchema(ModelSchema):
    loc = GeographySerializationField(attribute='loc')
    class Meta:
        model = Location
        sqla_session = db.session
        model_converter = GeoConverter

提案による他の配管:

class GeoConverter(ModelConverter):
    SQLA_TYPE_MAPPING = ModelConverter.SQLA_TYPE_MAPPING.copy()
    SQLA_TYPE_MAPPING.update({
        Geography: fields.Str
    })


class GeographySerializationField(fields.Field):
    def _serialize(self, value, attr, obj):
        if value is None:
            return value
        else:
            if isinstance(value, Geography):
                return json.dumps({'latitude': db.session.scalar(geo_funcs.ST_X(value)), 'longitude': db.session.scalar(geo_funcs.ST_Y(value))})
            else:
                return None

    def _deserialize(self, value, attr, data):
        """Deserialize value. Concrete :class:`Field` classes should implement this method.

        :param value: The value to be deserialized.
        :param str attr: The attribute/key in `data` to be deserialized.
        :param dict data: The raw input data passed to the `Schema.load`.
        :raise ValidationError: In case of formatting or validation failure.
        :return: The deserialized value.

        .. versionchanged:: 2.0.0
            Added ``attr`` and ``data`` parameters.
        """
        if value is None:
            return value
        else:
            if isinstance(value, Geography):
                return {'latitude': db.session.scalar(geo_funcs.ST_X(value)), 'longitude': db.session.scalar(geo_funcs.ST_Y(value))}
            else:
                return None

コードの実行中:

from app.users.serialize import *
from app.model.meta.schema import Location
l = LocationSchema()
loc = Location(27.685994, 85.317815)
r = l.load(loc)
print r

私が得る結果は次のとおりです。

UnmarshalResult(data={}, errors={u'_schema': [u'Invalid input type.']})
4

2 に答える 2

7

ModelConverter クラスをオーバーライドして、geography フィールドのカスタム マッピングを指定できます。ここで Jair Perrut の回答を参照してくださいマシュマロを使用してカスタム sqlalchemy フィールドをシリアル化する方法は?

from marshmallow_sqlalchemy import ModelConverter
from marshmallow import fields

class GeoConverter(ModelConverter):
    SQLA_TYPE_MAPPING = ModelConverter.SQLA_TYPE_MAPPING.copy()
    SQLA_TYPE_MAPPING.update({
        Geography: fields.Str
    })

class Meta:
    model = Address
    sqla_session = session
    model_converter = GeoConverter
于 2016-01-21T18:33:52.907 に答える