gns3-server/gns3server/db/models/base.py

#!/usr/bin/env python
#
# Copyright (C) 2020 GNS3 Technologies Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import uuid

from fastapi.encoders import jsonable_encoder
from sqlalchemy import Column, DateTime, func, inspect
from sqlalchemy.types import TypeDecorator, CHAR
from sqlalchemy.dialects.postgresql import UUID
from sqlalchemy.ext.declarative import as_declarative


@as_declarative()
class Base:

    def asdict(self):

        return {c.key: getattr(self, c.key)
                for c in inspect(self).mapper.column_attrs}

    def asjson(self):

        return jsonable_encoder(self.asdict())


class GUID(TypeDecorator):
    """
    Platform-independent GUID type.
    Uses PostgreSQL's UUID type, otherwise uses
    CHAR(32), storing as stringified hex values.
    """

    impl = CHAR

    def load_dialect_impl(self, dialect):
        if dialect.name == 'postgresql':
            return dialect.type_descriptor(UUID())
        else:
            return dialect.type_descriptor(CHAR(32))

    def process_bind_param(self, value, dialect):
        if value is None:
            return value
        elif dialect.name == 'postgresql':
            return str(value)
        else:
            if not isinstance(value, uuid.UUID):
                return "%.32x" % uuid.UUID(value).int
            else:
                # hexstring
                return "%.32x" % value.int

    def process_result_value(self, value, dialect):
        if value is None:
            return value
        else:
            if not isinstance(value, uuid.UUID):
                value = uuid.UUID(value)
            return value


class BaseTable(Base):

    __abstract__ = True

    created_at = Column(DateTime, default=func.current_timestamp())
    updated_at = Column(DateTime,
                        default=func.current_timestamp(),
                        onupdate=func.current_timestamp())


def generate_uuid():
    return str(uuid.uuid4())