gestioCOF/shared/views/autocomplete.py
2020-05-05 22:30:17 +02:00

64 lines
2 KiB
Python

from typing import Generic, Iterable, Type, TypeVar
from dal import autocomplete # type: ignore
from django.db.models import Model, Q
M = TypeVar("M", bound=Model)
class ModelSearch(Generic[M]):
"""Basic search engine for models based on filtering.
As the type hints indicate, the class is generic with respect to the model. This
means that the ``search`` method only returns instances of the model specified as
the ``model`` class attribute in subclasses.
The ``search_fields`` attributes indicates which fields to search in during the
search.
Example:
>>> from django.contrib.auth.models import User
>>>
>>> class UserSearch(ModelSearch):
... model = User
... search_fields = ["username", "first_name", "last_name"]
>>>
>>> user_search = UserSearch() # has type ModelSearch[User]
>>> user_search.search(["toto", "foo"]) # returns a queryset of Users
"""
model: Type[M]
search_fields: Iterable[str]
def get_queryset_filter(self, keywords: Iterable[str]) -> Q:
filter_q = Q()
if not keywords:
return filter_q
for keyword in keywords:
kw_filter = Q()
for field in self.search_fields:
kw_filter |= Q(**{"{}__icontains".format(field): keyword})
filter_q &= kw_filter
return filter_q
def search(self, keywords: Iterable[str]) -> Iterable[M]:
"""Returns the queryset of model instances matching all the keywords.
The semantic of the search is the following: a model instance appears in the
search results iff all of the keywords given as arguments occur in at least one
of the search fields.
"""
return self.model.objects.filter(self.get_queryset_filter(keywords))
class Select2QuerySetView(ModelSearch, autocomplete.Select2QuerySetView):
"""Compatibility layer between ModelSearch and Select2QuerySetView."""
def get_queryset(self):
keywords = self.q.split()
return super().search(keywords)