118 lines
4.0 KiB
Python
118 lines
4.0 KiB
Python
import pprint
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import string
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import uuid
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from random import choices
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from typing import Dict, List, TYPE_CHECKING, Union
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from weakref import proxy
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from orm.fields import ForeignKey
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if TYPE_CHECKING: # pragma no cover
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from orm.models import Model
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def get_table_alias() -> str:
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return "".join(choices(string.ascii_uppercase, k=2)) + uuid.uuid4().hex[:4]
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def get_relation_config(
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relation_type: str, table_name: str, field: ForeignKey
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) -> Dict[str, str]:
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alias = get_table_alias()
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config = {
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"type": relation_type,
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"table_alias": alias,
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"source_table": table_name
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if relation_type == "primary"
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else field.to.__tablename__,
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"target_table": field.to.__tablename__
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if relation_type == "primary"
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else table_name,
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}
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return config
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class RelationshipManager:
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def __init__(self) -> None:
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self._relations = dict()
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def add_relation_type(
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self, relations_key: str, reverse_key: str, field: ForeignKey, table_name: str
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) -> None:
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if relations_key not in self._relations:
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self._relations[relations_key] = get_relation_config(
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"primary", table_name, field
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)
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if reverse_key not in self._relations:
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self._relations[reverse_key] = get_relation_config(
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"reverse", table_name, field
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)
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def deregister(self, model: "Model") -> None:
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# print(f'deregistering {model.__class__.__name__}, {model._orm_id}')
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for rel_type in self._relations.keys():
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if model.__class__.__name__.lower() in rel_type.lower():
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if model._orm_id in self._relations[rel_type]:
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del self._relations[rel_type][model._orm_id]
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def add_relation(
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self,
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parent_name: str,
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child_name: str,
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parent: "Model",
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child: "Model",
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virtual: bool = False,
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) -> None:
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parent_id = parent._orm_id
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child_id = child._orm_id
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if virtual:
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child_name, parent_name = parent_name, child_name
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child_id, parent_id = parent_id, child_id
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child, parent = parent, proxy(child)
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else:
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child = proxy(child)
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parents_list = self._relations[
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parent_name.lower().title() + "_" + child_name + "s"
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].setdefault(parent_id, [])
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self.append_related_model(parents_list, child)
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children_list = self._relations[
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child_name.lower().title() + "_" + parent_name
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].setdefault(child_id, [])
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self.append_related_model(children_list, parent)
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def append_related_model(
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self, relations_list: List["Model"], model: "Model"
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) -> None:
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for x in relations_list:
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try:
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if x.__same__(model):
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return
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except ReferenceError:
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continue
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relations_list.append(model)
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def contains(self, relations_key: str, object: "Model") -> bool:
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if relations_key in self._relations:
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return object._orm_id in self._relations[relations_key]
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return False
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def get(self, relations_key: str, object: "Model") -> Union["Model", List["Model"]]:
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if relations_key in self._relations:
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if object._orm_id in self._relations[relations_key]:
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if self._relations[relations_key]["type"] == "primary":
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return self._relations[relations_key][object._orm_id][0]
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return self._relations[relations_key][object._orm_id]
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def resolve_relation_join(self, from_table: str, to_table: str) -> str:
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for k, v in self._relations.items():
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if v["source_table"] == from_table and v["target_table"] == to_table:
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return self._relations[k]["table_alias"]
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return ""
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def __str__(self) -> str: # pragma no cover
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return pprint.pformat(self._relations, indent=4, width=1)
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def __repr__(self) -> str: # pragma no cover
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return self.__str__()
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