125 lines
4.8 KiB
Python
125 lines
4.8 KiB
Python
import uuid
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from datetime import datetime
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from typing import Set
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from flask import g
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from sqlalchemy.dialects.postgresql import UUID
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from sqlalchemy.sql import expression
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from sqlalchemy_utils import LtreeType
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from sqlalchemy_utils.types.ltree import LQUERY
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from teal.db import UUIDLtree
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from ereuse_devicehub.db import db
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from ereuse_devicehub.resources.device.models import Device
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from ereuse_devicehub.resources.models import STR_SIZE, Thing
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from ereuse_devicehub.resources.user.models import User
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class Lot(Thing):
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id = db.Column(UUID(as_uuid=True), primary_key=True) # uuid is generated on init by default
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name = db.Column(db.Unicode(STR_SIZE), nullable=False)
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closed = db.Column(db.Boolean, default=False, nullable=False)
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closed.comment = """
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A closed lot cannot be modified anymore.
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"""
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devices = db.relationship(Device,
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backref=db.backref('parents', lazy=True, collection_class=set),
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secondary=lambda: LotDevice.__table__,
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collection_class=set)
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def __init__(self, name: str, closed: bool = closed.default.arg) -> None:
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"""
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Initializes a lot
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:param name:
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:param closed:
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"""
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super().__init__(id=uuid.uuid4(), name=name, closed=closed)
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Path(self) # Lots have always one edge per default.
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def add_child(self, child: 'Lot'):
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"""Adds a child to this lot."""
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Path.add(self.id, child.id)
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db.session.refresh(self) # todo is this useful?
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db.session.refresh(child)
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def remove_child(self, child: 'Lot'):
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Path.delete(self.id, child.id)
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def __contains__(self, child: 'Lot'):
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return Path.has_lot(self.id, child.id)
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@classmethod
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def roots(cls):
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"""Gets the lots that are not under any other lot."""
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return set(cls.query.join(cls.paths).filter(db.func.nlevel(Path.path) == 1).all())
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def __repr__(self) -> str:
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return '<Lot {0.name} devices={0.devices!r}>'.format(self)
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class LotDevice(db.Model):
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device_id = db.Column(db.BigInteger, db.ForeignKey(Device.id), primary_key=True)
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lot_id = db.Column(UUID(as_uuid=True), db.ForeignKey(Lot.id), primary_key=True)
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created = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
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author_id = db.Column(UUID(as_uuid=True),
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db.ForeignKey(User.id),
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nullable=False,
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default=lambda: g.user.id)
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author = db.relationship(User, primaryjoin=author_id == User.id)
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author_id.comment = """
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The user that put the device in the lot.
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"""
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class Path(db.Model):
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id = db.Column(db.UUID(as_uuid=True),
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primary_key=True,
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server_default=db.text('gen_random_uuid()'))
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lot_id = db.Column(db.UUID(as_uuid=True), db.ForeignKey(Lot.id), nullable=False)
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lot = db.relationship(Lot,
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backref=db.backref('paths', lazy=True, collection_class=set),
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primaryjoin=Lot.id == lot_id)
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path = db.Column(LtreeType, nullable=False)
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created = db.Column(db.TIMESTAMP(timezone=True), server_default=db.text('CURRENT_TIMESTAMP'))
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created.comment = """
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When Devicehub created this.
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"""
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__table_args__ = (
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# dag.delete_edge needs to disable internally/temporarily the unique constraint
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db.UniqueConstraint(path, name='path_unique', deferrable=True, initially='immediate'),
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db.Index('path_gist', path, postgresql_using='gist'),
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db.Index('path_btree', path, postgresql_using='btree')
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)
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def __init__(self, lot: Lot) -> None:
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super().__init__(lot=lot)
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self.path = UUIDLtree(lot.id)
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def children(self) -> Set['Path']:
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"""Get the children edges."""
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# todo is it useful? test it when first usage
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# From https://stackoverflow.com/a/41158890
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exp = '*.{}.*{{1}}'.format(self.lot_id)
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return set(self.query
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.filter(self.path.lquery(expression.cast(exp, LQUERY)))
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.distinct(self.__class__.lot_id)
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.all())
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@classmethod
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def add(cls, parent_id: uuid.UUID, child_id: uuid.UUID):
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"""Creates an edge between parent and child."""
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db.session.execute(db.func.add_edge(str(parent_id), str(child_id)))
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@classmethod
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def delete(cls, parent_id: uuid.UUID, child_id: uuid.UUID):
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"""Deletes the edge between parent and child."""
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db.session.execute(db.func.delete_edge(str(parent_id), str(child_id)))
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@classmethod
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def has_lot(cls, parent_id: uuid.UUID, child_id: uuid.UUID) -> bool:
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return bool(db.session.execute(
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"SELECT 1 from path where path ~ '*.{}.*.{}.*'".format(
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str(parent_id).replace('-', '_'), str(child_id).replace('-', '_'))
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).first())
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