API Views/serializers/tests for activity (#141)

api/funkwhale_api/activity/utils.py

@@ -0,0 +1,64 @@
+from django.db import models
+
+from funkwhale_api.common import fields
+from funkwhale_api.favorites.models import TrackFavorite
+from funkwhale_api.history.models import Listening
+
+
+def combined_recent(limit, **kwargs):
+    datetime_field = kwargs.pop('datetime_field', 'creation_date')
+    source_querysets = {
+        qs.model._meta.label: qs for qs in kwargs.pop('querysets')
+    }
+    querysets = {
+        k: qs.annotate(
+            __type=models.Value(
+                qs.model._meta.label, output_field=models.CharField()
+            )
+        ).values('pk', datetime_field, '__type')
+        for k, qs in source_querysets.items()
+    }
+    _qs_list = list(querysets.values())
+    union_qs = _qs_list[0].union(*_qs_list[1:])
+    records = []
+    for row in union_qs.order_by('-{}'.format(datetime_field))[:limit]:
+        records.append({
+            'type': row['__type'],
+            'when': row[datetime_field],
+            'pk': row['pk']
+        })
+    # Now we bulk-load each object type in turn
+    to_load = {}
+    for record in records:
+        to_load.setdefault(record['type'], []).append(record['pk'])
+    fetched = {}
+
+    for key, pks in to_load.items():
+        for item in source_querysets[key].filter(pk__in=pks):
+            fetched[(key, item.pk)] = item
+
+    # Annotate 'records' with loaded objects
+    for record in records:
+        record['object'] = fetched[(record['type'], record['pk'])]
+    return records
+
+
+def get_activity(user, limit=20):
+    query = fields.privacy_level_query(
+        user, lookup_field='user__privacy_level')
+    querysets = [
+        Listening.objects.filter(query).select_related(
+            'track',
+            'user',
+            'track__artist',
+            'track__album__artist',
+        ),
+        TrackFavorite.objects.filter(query).select_related(
+            'track',
+            'user',
+            'track__artist',
+            'track__album__artist',
+        ),
+    ]
+    records = combined_recent(limit=limit, querysets=querysets)
+    return [r['object'] for r in records]