如何使用 Flask Marshmallow 將嵌套模式連接到一個 JSON 對象中

Question

我在將兩個模式連接到一個嵌套的 JSON 對象中時遇到問題。 此 API 返回 JSON 作為 3 個相關表連接查詢的結果。 在我進行查詢之后，我使用了從這里引用的兩個 Marshmellow 模式。 但是響應並不像預期的那樣，這里是響應：

{
  "message": "success",
  "device": [
    {
      "device_name": "Kamar Tidur Utama"
    }
  ],
  "sensor": [
    {
      "value": 23.3683,
      "sensor_name": "Temperature"
    },
    {
      "value": 0.0,
      "sensor_name": "Motion"
    },
    {
      "value": 90.12,
      "sensor_name": "Humidity"
    },
    {
      "value": 15.8667,
      "sensor_name": "Current 1"
    },
    {
      "value": 15.0333,
      "sensor_name": "Current 2"
    }
  ]
}

我想要的是“傳感器”對象放在“設備”中。 很多設備都有很多這樣的傳感器：

{
  "message": "success",
  "device": [
    {
        "device_name": "Kamar Tidur Utama"
        "sensor": [
            {
            "value": 23.3683,
            "sensor_name": "Temperature"
            },
            {
            "value": 0.0,
            "sensor_name": "Motion"
            },
            {
            "value": 90.12,
            "sensor_name": "Humidity"
            },
            {
            "value": 15.8667,
            "sensor_name": "Current 1"
            },
            {
            "value": 15.0333,
            "sensor_name": "Current 2"
            }
        ]
    }
  ]
}

這是我的三個相關模型：

Device.py（一種查詢API的方法）

 @classmethod
    def get_device_sensor(cls):
        device_sensor_schema = DeviceSensorSchema(many=True)
        sensor_value_schema = SensorValueSchema(many=True)

        device = Device.query.join(SensorData, Device.id == SensorData.device_id)\
            .add_columns(Device.name.label('device_name'))
        print(device)
        sensor = Sensor.query.join(SensorData, Sensor.id == SensorData.sensor_id)\
            .add_columns(Sensor.name.label('sensor_name'), SensorData.value.label('value'))

        res_device = device_sensor_schema.dump(device, many=True)
        res_sensor = sensor_value_schema.dump(sensor, many=True)
        if device:
            return jsonify({'message': 'success', 'device': res_device, 'sensor': res_sensor})
        else:
            return {'message': 'Table device is empty'}, 404

Device.py（兩個棉花糖架構）

class SensorValueSchema(ma.Schema):
    sensor_name = fields.String()
    value = fields.Float()
    ordered=True

class DeviceSensorSchema(Schema):
    device_name = fields.String()
    sensors = fields.List(fields.Nested(SensorValueSchema))

Device.py（模型類）

class Device(db.Model):
    __tablename__ = "devices"
    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('users.id'))
    name = db.Column(db.String(255))
    serial_number = db.Column(db.String(255), unique=True)
    used_relay = db.Column(db.Integer, default=0)
    created_at = db.Column(db.DateTime(timezone=True), server_default=db.func.now())
    updated_at = db.Column(db.DateTime(timezone=True), onupdate=db.func.now())
    switches = db.relationship('Switch', backref='device', lazy='dynamic')
    power_usages = db.relationship('PowerUsage', backref='device', lazy='dynamic')
    power_expenses = db.relationship('PowerExpense', backref='device', lazy='dynamic')
    behaviors_dataset = db.relationship('BehaviorDataset', backref='device', lazy='dynamic')
    usage_histories = db.relationship('UsageHistory', backref='device', lazy='dynamic')
    sensors_data = db.relationship('SensorData', backref='device', lazy='dynamic')
    notifications = db.relationship('Notification', backref='device', lazy='dynamic')
    device_serial_number = db.relationship('DeviceSerialNumber', backref='device', lazy='dynamic')

Sensor.py（模型類）

class Sensor(db.Model):
    __tablename__ = "sensors"
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(120))
    created_at = db.Column(db.DateTime(timezone=True), server_default=db.func.now())
    updated_at = db.Column(db.DateTime(timezone=True), onupdate=db.func.now())
    sensors_data = db.relationship('SensorData', backref='sensor', lazy='dynamic')

SensorData.py（模型類）

class SensorData(db.Model):
    __tablename__ = "sensors_data"
    id = db.Column(db.Integer, primary_key=True)
    device_id = db.Column(db.Integer, db.ForeignKey('devices.id'))
    sensor_id = db.Column(db.Integer, db.ForeignKey('sensors.id'))
    value = db.Column(db.Float)
    created_at = db.Column(db.DateTime(timezone=True), server_default=db.func.now())
    updated_at = db.Column(db.DateTime(timezone=True), onupdate=db.func.now())

Answer 1

您應該將sensor對象分配給device列表中的每個條目。 我達到理想結果的愚蠢方式：

 @classmethod
    def get_device_sensor(cls):
        device_sensor_schema = DeviceSensorSchema(many=True)
        sensor_value_schema = SensorValueSchema(many=True)

        device = Device.query.join(SensorData, Device.id == SensorData.device_id)\
            .add_columns(Device.name.label('device_name'))
        print(device)
        sensor = Sensor.query.join(SensorData, Sensor.id == SensorData.sensor_id)\
            .add_columns(Sensor.name.label('sensor_name'), SensorData.value.label('value'))

        res_device[0].sensors = sensor
        res_device = device_sensor_schema.dump(device, many=True)

        if device:
            return jsonify({'message': 'success', 'device': res_device})
        else:
            return {'message': 'Table device is empty'}, 404

解決這個問題的更好方法是使用映射的 SQLAlchemy 對象。 在這種情況下Device.sensors_data 。