from datetime import datetime, timezone from flask_sqlalchemy import event from ereuse_devicehub.db import db STR_SIZE = 64 STR_BIG_SIZE = 128 STR_SM_SIZE = 32 STR_XSM_SIZE = 16 class Thing(db.Model): """The base class of all Devicehub resources. This is a loose copy of `schema.org's Thing class `_ using only needed fields. """ __abstract__ = True updated = db.Column(db.TIMESTAMP(timezone=True), nullable=False, index=True, server_default=db.text('CURRENT_TIMESTAMP')) updated.comment = """The last time Devicehub recorded a change for this thing. """ created = db.Column(db.TIMESTAMP(timezone=True), nullable=False, index=True, server_default=db.text('CURRENT_TIMESTAMP')) created.comment = """When Devicehub created this.""" def __init__(self, **kwargs) -> None: # We need to set 'created' before sqlalchemy inits the class # to be able to use sorted containers self.created = kwargs.get('created', datetime.now(timezone.utc)) super().__init__(**kwargs) def update_object_timestamp(mapper, connection, thing_obj): """ This function update the stamptime of field updated """ thing_obj.updated = datetime.now(timezone.utc) def listener_reset_field_updated_in_actual_time(thing_obj): """ This function launch a event than listen like a signal when some object is saved """ event.listen(thing_obj, 'before_update', update_object_timestamp, propagate=True)