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e097e8a12f
May your database queries be much reduced with minimal effort. co-authored-by: Andreas Pelme <andreas@pelme.se> co-authored-by: Simon Charette <charette.s@gmail.com> co-authored-by: Jacob Walls <jacobtylerwalls@gmail.com>
52 lines
1.1 KiB
Python
52 lines
1.1 KiB
Python
from django.core.exceptions import FieldFetchBlocked
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class FetchMode:
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__slots__ = ()
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track_peers = False
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def fetch(self, fetcher, instance):
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raise NotImplementedError("Subclasses must implement this method.")
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class FetchOne(FetchMode):
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__slots__ = ()
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def fetch(self, fetcher, instance):
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fetcher.fetch_one(instance)
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FETCH_ONE = FetchOne()
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class FetchPeers(FetchMode):
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__slots__ = ()
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track_peers = True
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def fetch(self, fetcher, instance):
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instances = [
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peer
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for peer_weakref in instance._state.peers
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if (peer := peer_weakref()) is not None
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]
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if len(instances) > 1:
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fetcher.fetch_many(instances)
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else:
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fetcher.fetch_one(instance)
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FETCH_PEERS = FetchPeers()
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class Raise(FetchMode):
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__slots__ = ()
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def fetch(self, fetcher, instance):
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klass = instance.__class__.__qualname__
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field_name = fetcher.field.name
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raise FieldFetchBlocked(f"Fetching of {klass}.{field_name} blocked.") from None
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RAISE = Raise()
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