|
| 1 | +from collections import defaultdict |
| 2 | +from typing import Any, Dict, Optional, Sequence, Tuple, Type |
| 3 | + |
| 4 | +from django.apps import apps |
| 5 | +from django.db import models as django_models |
| 6 | +from django.db.models.options import Options |
| 7 | +from django.utils.translation import gettext_lazy as _ |
| 8 | + |
| 9 | +from ..remote import get_remote_object_class, get_local_resource_prefix |
| 10 | + |
| 11 | + |
| 12 | +class DABContentTypeManager(django_models.Manager["DABContentType"]): |
| 13 | + """Manager storing DABContentType objects in a local cache like original ContentType. |
| 14 | +
|
| 15 | + The major structural difference is that the cache keys have to add the service reference. |
| 16 | + """ |
| 17 | + |
| 18 | + use_in_migrations = True |
| 19 | + |
| 20 | + def __init__(self, *args: Any, **kwargs: Any) -> None: |
| 21 | + super().__init__(*args, **kwargs) |
| 22 | + self._cache: Dict[str, Dict[Tuple[str, str, str] | int, "DABContentType"]] = {} |
| 23 | + |
| 24 | + def clear_cache(self) -> None: |
| 25 | + self._cache.clear() |
| 26 | + |
| 27 | + def create(self, *args: Any, **kwargs: Any) -> "DABContentType": |
| 28 | + obj = super().create(*args, **kwargs) |
| 29 | + self._add_to_cache(self.db, obj) |
| 30 | + return obj |
| 31 | + |
| 32 | + def _add_to_cache(self, using: str, ct: "DABContentType") -> None: |
| 33 | + """Store ``ct`` in the manager cache for the given database alias.""" |
| 34 | + key = (ct.service, ct.app_label, ct.model) |
| 35 | + self._cache.setdefault(using, {})[key] = ct |
| 36 | + self._cache.setdefault(using, {})[ct.id] = ct |
| 37 | + |
| 38 | + def _get_from_cache(self, opts: Options, service: str) -> "DABContentType": |
| 39 | + """Return a cached ``DABContentType`` for ``opts`` and ``service``.""" |
| 40 | + key = (service, opts.app_label, opts.model_name) |
| 41 | + return self._cache[self.db][key] |
| 42 | + |
| 43 | + def _get_opts(self, model: Type[django_models.Model], for_concrete_model: bool) -> Options: |
| 44 | + """Return the ``Options`` object for ``model``.""" |
| 45 | + return model._meta.concrete_model._meta if for_concrete_model else model._meta |
| 46 | + |
| 47 | + def get_for_model( |
| 48 | + self, |
| 49 | + model: Type[django_models.Model], |
| 50 | + for_concrete_model: bool = True, |
| 51 | + service: Optional[str] = None, |
| 52 | + ) -> "DABContentType": |
| 53 | + if service is None: |
| 54 | + service = get_local_resource_prefix() |
| 55 | + opts = self._get_opts(model, for_concrete_model) |
| 56 | + try: |
| 57 | + return self._get_from_cache(opts, service) |
| 58 | + except KeyError: |
| 59 | + pass |
| 60 | + |
| 61 | + try: |
| 62 | + ct = self.get(service=service, app_label=opts.app_label, model=opts.model_name) |
| 63 | + except self.model.DoesNotExist: |
| 64 | + ct, _ = self.get_or_create( |
| 65 | + service=service, |
| 66 | + app_label=opts.app_label, |
| 67 | + model=opts.model_name, |
| 68 | + ) |
| 69 | + self._add_to_cache(self.db, ct) |
| 70 | + return ct |
| 71 | + |
| 72 | + def get_for_models( |
| 73 | + self, |
| 74 | + *model_list: Type[django_models.Model], |
| 75 | + for_concrete_models: bool = True, |
| 76 | + service: Optional[str] = None, |
| 77 | + ) -> Dict[Type[django_models.Model], "DABContentType"]: |
| 78 | + """Return ``DABContentType`` objects for each model in ``model_list``.""" |
| 79 | + if service is None: |
| 80 | + service = get_local_resource_prefix() |
| 81 | + results: Dict[Type[django_models.Model], "DABContentType"] = {} |
| 82 | + needed_models: Dict[str, set[str]] = defaultdict(set) |
| 83 | + needed_opts: Dict[Tuple[str, str], list[Type[django_models.Model]]] = defaultdict(list) |
| 84 | + for model in model_list: |
| 85 | + opts = self._get_opts(model, for_concrete_models) |
| 86 | + try: |
| 87 | + ct = self._get_from_cache(opts, service) |
| 88 | + except KeyError: |
| 89 | + needed_models[opts.app_label].add(opts.model_name) |
| 90 | + needed_opts[(opts.app_label, opts.model_name)].append(model) |
| 91 | + else: |
| 92 | + results[model] = ct |
| 93 | + |
| 94 | + if needed_opts: |
| 95 | + condition = django_models.Q( |
| 96 | + *( |
| 97 | + django_models.Q( |
| 98 | + ("service", service), |
| 99 | + ("app_label", app_label), |
| 100 | + ("model__in", models), |
| 101 | + ) |
| 102 | + for app_label, models in needed_models.items() |
| 103 | + ), |
| 104 | + _connector=django_models.Q.OR, |
| 105 | + ) |
| 106 | + cts = self.filter(condition) |
| 107 | + for ct in cts: |
| 108 | + opts_models = needed_opts.pop((ct.app_label, ct.model), []) |
| 109 | + for model in opts_models: |
| 110 | + results[model] = ct |
| 111 | + self._add_to_cache(self.db, ct) |
| 112 | + for (app_label, model_name), opts_models in needed_opts.items(): |
| 113 | + ct = self.create(service=service, app_label=app_label, model=model_name) |
| 114 | + self._add_to_cache(self.db, ct) |
| 115 | + for model in opts_models: |
| 116 | + results[model] = ct |
| 117 | + return results |
| 118 | + |
| 119 | + def get_by_natural_key(self, *args: str) -> "DABContentType": |
| 120 | + """Return the content type identified by its natural key.""" |
| 121 | + if len(args) == 2: |
| 122 | + service = get_local_resource_prefix() |
| 123 | + app_label, model = args |
| 124 | + else: |
| 125 | + service, app_label, model = args |
| 126 | + key = (service, app_label, model) |
| 127 | + try: |
| 128 | + return self._cache[self.db][key] |
| 129 | + except KeyError: |
| 130 | + ct = self.get(service=service, app_label=app_label, model=model) |
| 131 | + self._add_to_cache(self.db, ct) |
| 132 | + return ct |
| 133 | + |
| 134 | + def get_for_id(self, id: int) -> "DABContentType": |
| 135 | + """Return the content type with primary key ``id`` from the cache.""" |
| 136 | + try: |
| 137 | + return self._cache[self.db][id] |
| 138 | + except KeyError: |
| 139 | + ct = self.get(pk=id) |
| 140 | + self._add_to_cache(self.db, ct) |
| 141 | + return ct |
| 142 | + |
| 143 | + |
| 144 | +class DABContentType(django_models.Model): |
| 145 | + """Like Django ContentType model but scoped by service.""" |
| 146 | + |
| 147 | + service = django_models.CharField( |
| 148 | + max_length=100, |
| 149 | + default=get_local_resource_prefix, |
| 150 | + help_text=_("service namespace to track what service this type is for. Can have a value of shared, which indicates it is synchronized."), |
| 151 | + ) |
| 152 | + app_label = django_models.CharField( |
| 153 | + max_length=100, |
| 154 | + help_text=_("Django app that the model is in. This is an internal technical detail that does not affect API use."), |
| 155 | + ) |
| 156 | + model = django_models.CharField( |
| 157 | + max_length=100, |
| 158 | + help_text=_("Name of the type according to the Django ORM Meta model_name convention. Comes from the python class, but lowercase with no spaces."), |
| 159 | + ) |
| 160 | + |
| 161 | + objects = DABContentTypeManager() |
| 162 | + |
| 163 | + class Meta: |
| 164 | + unique_together = [ |
| 165 | + ("service", "app_label", "model"), |
| 166 | + ] |
| 167 | + |
| 168 | + def __str__(self) -> str: |
| 169 | + return self.app_labeled_name |
| 170 | + |
| 171 | + @property |
| 172 | + def name(self) -> str: |
| 173 | + model = self.model_class() |
| 174 | + if not model: |
| 175 | + return self.model |
| 176 | + return str(model._meta.verbose_name) |
| 177 | + |
| 178 | + @property |
| 179 | + def app_labeled_name(self) -> str: |
| 180 | + model = self.model_class() |
| 181 | + if not model: |
| 182 | + return self.model |
| 183 | + return f"{model._meta.app_config.verbose_name} | {model._meta.verbose_name}" |
| 184 | + |
| 185 | + def model_class(self) -> Optional[Type[django_models.Model]]: |
| 186 | + """Return the model class if available for the current service.""" |
| 187 | + if self.service not in ("shared", get_local_resource_prefix()): |
| 188 | + return None |
| 189 | + try: |
| 190 | + return apps.get_model(self.app_label, self.model) |
| 191 | + except LookupError: |
| 192 | + return None |
| 193 | + |
| 194 | + def get_object_for_this_type(self, **kwargs: Any) -> django_models.Model: |
| 195 | + """Return the object referenced by this content type.""" |
| 196 | + model = self.model_class() |
| 197 | + if model is None: |
| 198 | + object_id = kwargs.get("pk") or kwargs.get("id") or kwargs.get("pk__exact") or kwargs.get("id__exact") |
| 199 | + if object_id is None: |
| 200 | + raise LookupError("Model not available in this service") |
| 201 | + return get_remote_object_class()(self, object_id) |
| 202 | + return model._base_manager.get(**kwargs) |
| 203 | + |
| 204 | + def get_all_objects_for_this_type(self, **kwargs: Any) -> django_models.QuerySet | Sequence[django_models.Model]: |
| 205 | + """Return all objects referenced by this content type.""" |
| 206 | + model = self.model_class() |
| 207 | + if model is None: |
| 208 | + ids = kwargs.get("pk__in") or kwargs.get("id__in") or (kwargs.get("pk") and [kwargs["pk"]]) or (kwargs.get("id") and [kwargs["id"]]) |
| 209 | + if not ids: |
| 210 | + return [] |
| 211 | + return [get_remote_object_class()(self, obj_id) for obj_id in ids] |
| 212 | + return list(model._base_manager.filter(**kwargs)) |
| 213 | + |
| 214 | + def natural_key(self) -> Tuple[str, str, str]: |
| 215 | + return (self.service, self.app_label, self.model) |
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