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