Serialization

Before sending data through the api, we have to serialize the Python objects. We use Marshmallow for this.

In crc/models/data_store.py, we define DataStoreModel, the database model for our data store, where we can save key/value pairs for studies, users, and files.

from flask_marshmallow.sqla import SQLAlchemyAutoSchema
from sqlalchemy import func
from crc import db

class DataStoreModel(db.Model):
    __tablename__ = 'data_store'
    id = db.Column(db.Integer, primary_key=True)
    last_updated = db.Column(db.DateTime(timezone=True), server_default=func.now())
    key = db.Column(db.String, nullable=False)
    workflow_id = db.Column(db.Integer)
    study_id = db.Column(db.Integer, nullable=True)
    task_id = db.Column(db.String)
    spec_id = db.Column(db.String)
    user_id = db.Column(db.String, nullable=True)
    file_id = db.Column(db.Integer, db.ForeignKey('file.id'), nullable=True)
    value = db.Column(db.String)

In the same file, we also define DataStoreSchema, which we use to serialize the data.

class DataStoreSchema(SQLAlchemyAutoSchema):
    class Meta:
        model = DataStoreModel
        load_instance = True
        sqla_session = db.session

Note that this is the same way we serialized the response for ApiError in ApiErrorSchema.

For more information about Marshmallow, see the documentation.