konova/api/utils/serializer/serializer.py

"""
Author: Michel Peltriaux
Organization: Struktur- und Genehmigungsdirektion Nord, Rhineland-Palatinate, Germany
Contact: michel.peltriaux@sgdnord.rlp.de
Created on: 24.01.22

"""
import json
from abc import abstractmethod

from django.contrib.gis import geos
from django.contrib.gis.geos import GEOSGeometry


class AbstractModelAPISerializer:
    model = None
    lookup = None
    properties_data = None

    class Meta:
        abstract = True

    def __init__(self, *args, **kwargs):
        self.lookup = {
            "id": None,  # must be set
            "deleted__isnull": True,
            "users__in": [],  # must be set
        }
        super().__init__(*args, **kwargs)

    @abstractmethod
    def model_to_geo_json(self, entry):
        """ Defines the model as geo json

        Args:
            entry (): The found entry from the database

        Returns:

        """
        raise NotImplementedError("Must be implemented in subclasses")

    @abstractmethod
    def extend_properties_data(self, entry):
        """ Defines the 'properties' part of geo json

        Args:
            entry (): The found entry from the database

        Returns:

        """
        raise NotImplementedError("Must be implemented in subclasses")

    @abstractmethod
    def prepare_lookup(self, _id, user):
        """ Updates lookup dict for db fetching

        Args:
            _id (str): The object's id
            user (User): The user requesting for

        Returns:

        """
        self.lookup["id"] = _id
        self.lookup["users__in"] = [user]

    def fetch_and_serialize(self):
        """ Serializes the model entry according to the given lookup data

        Args:

        Returns:
            serialized_data (dict)
        """
        entry = self.model.objects.get(**self.lookup)
        serialized_data = self.model_to_geo_json(entry)
        return serialized_data

    @abstractmethod
    def update_model_from_json(self, id, json_model, user):
        """ Updates an instance from given json data

        Args:
            id (str): The instance's to be updated
            json_model (dict): JSON data
            user (User): The performing user

        Returns:

        """
        raise NotImplementedError("Must be implemented in subclasses")

    @abstractmethod
    def create_model_from_json(self, json_model, user):
        """ Creates a new instance from given json data

        Args:
            json_model (dict): JSON data
            user (User): The performing user

        Returns:

        """
        raise NotImplementedError("Must be implemented in subclasses")

    def create_geometry_from_json(self, geojson) -> GEOSGeometry:
        """ Creates a GEOSGeometry object based on the given geojson

        Args:
            geojson (str|dict): The geojson as str or dict

        Returns:
            geometry (GEOSGeometry)
        """
        if isinstance(geojson, dict):
            geojson = json.dumps(geojson)
        geometry = geos.fromstr(geojson)
        return geometry