Serializers for paginated collections

api/config/settings/common.py

@@ -30,6 +30,9 @@ FUNKWHALE_HOSTNAME = urlsplit(FUNKWHALE_URL).netloc
 
 FEDERATION_ENABLED = env.bool('FEDERATION_ENABLED', default=True)
 FEDERATION_HOSTNAME = env('FEDERATION_HOSTNAME', default=FUNKWHALE_HOSTNAME)
+FEDERATION_COLLECTION_PAGE_SIZE = env.int(
+    'FEDERATION_COLLECTION_PAGE_SIZE', default=50
+)
 FEDERATION_MUSIC_NEEDS_APPROVAL = env.bool(
     'FEDERATION_MUSIC_NEEDS_APPROVAL', default=True
 )

api/funkwhale_api/federation/serializers.py

@@ -2,10 +2,13 @@ import urllib.parse
 
 from django.urls import reverse
 from django.conf import settings
+from django.core.paginator import Paginator
 
 from rest_framework import serializers
 from dynamic_preferences.registries import global_preferences_registry
 
+from funkwhale_api.common.utils import set_query_parameter
+
 from . import activity
 from . import models
 from . import utils
@@ -199,3 +202,66 @@ OBJECT_SERIALIZERS = {
     t: ObjectSerializer
     for t in activity.OBJECT_TYPES
 }
+
+
+class PaginatedCollectionSerializer(serializers.Serializer):
+
+    def to_representation(self, conf):
+        paginator = Paginator(
+            conf['items'],
+            conf.get('page_size', 20)
+        )
+        first = set_query_parameter(conf['id'], page=1)
+        current = first
+        last = set_query_parameter(conf['id'], page=paginator.num_pages)
+        d = {
+            'id': conf['id'],
+            'actor': conf['actor'].url,
+            'totalItems': paginator.count,
+            'type': 'Collection',
+            'current': current,
+            'first': first,
+            'last': last,
+        }
+        if self.context.get('include_ap_context', True):
+            d['@context'] = AP_CONTEXT
+        return d
+
+
+class CollectionPageSerializer(serializers.Serializer):
+
+    def to_representation(self, conf):
+        page = conf['page']
+        first = set_query_parameter(conf['id'], page=1)
+        last = set_query_parameter(conf['id'], page=page.paginator.num_pages)
+        id = set_query_parameter(conf['id'], page=page.number)
+        d = {
+            'id': id,
+            'partOf': conf['id'],
+            'actor': conf['actor'].url,
+            'totalItems': page.paginator.count,
+            'type': 'CollectionPage',
+            'first': first,
+            'last': last,
+            'items': [
+                conf['item_serializer'](
+                    i,
+                    context={
+                        'actor': conf['actor'],
+                        'include_ap_context': False}
+                ).data
+                for i in page.object_list
+            ]
+        }
+
+        if page.has_previous():
+            d['prev'] = set_query_parameter(
+                conf['id'], page=page.previous_page_number())
+
+        if page.has_previous():
+            d['next'] = set_query_parameter(
+                conf['id'], page=page.next_page_number())
+
+        if self.context.get('include_ap_context', True):
+            d['@context'] = AP_CONTEXT
+        return d

api/tests/federation/test_serializers.py

 from django.urls import reverse
+from django.core.paginator import Paginator
 
 from funkwhale_api.federation import keys
 from funkwhale_api.federation import models
 from funkwhale_api.federation import serializers
+from funkwhale_api.music.serializers import AudioSerializer
 
 
 def test_actor_serializer_from_ap(db):
@@ -163,3 +165,73 @@ def test_follow_serializer_to_ap(factories):
     }
 
     assert serializer.data == expected
+
+
+def test_paginated_collection_serializer(factories):
+    tfs = factories['music.TrackFile'].create_batch(size=5)
+    actor = factories['federation.Actor'](local=True)
+
+    conf = {
+        'id': 'https://test.federation/test',
+        'items': tfs,
+        'item_serializer': AudioSerializer,
+        'actor': actor,
+        'page_size': 2,
+    }
+    expected = {
+        '@context': [
+            'https://www.w3.org/ns/activitystreams',
+            'https://w3id.org/security/v1',
+            {},
+        ],
+        'type': 'Collection',
+        'id': conf['id'],
+        'actor': actor.url,
+        'totalItems': len(tfs),
+        'current': conf['id'] + '?page=1',
+        'last': conf['id'] + '?page=3',
+        'first': conf['id'] + '?page=1',
+    }
+
+    serializer = serializers.PaginatedCollectionSerializer(conf)
+
+    assert serializer.data == expected
+
+
+def test_collection_page_serializer(factories):
+    tfs = factories['music.TrackFile'].create_batch(size=5)
+    actor = factories['federation.Actor'](local=True)
+
+    conf = {
+        'id': 'https://test.federation/test',
+        'item_serializer': AudioSerializer,
+        'actor': actor,
+        'page': Paginator(tfs, 2).page(2),
+    }
+    expected = {
+        '@context': [
+            'https://www.w3.org/ns/activitystreams',
+            'https://w3id.org/security/v1',
+            {},
+        ],
+        'type': 'CollectionPage',
+        'id': conf['id'] + '?page=2',
+        'actor': actor.url,
+        'totalItems': len(tfs),
+        'partOf': conf['id'],
+        'prev': conf['id'] + '?page=1',
+        'next': conf['id'] + '?page=3',
+        'first': conf['id'] + '?page=1',
+        'last': conf['id'] + '?page=3',
+        'items': [
+            conf['item_serializer'](
+                i,
+                context={'actor': actor, 'include_ap_context': False}
+            ).data
+            for i in conf['page'].object_list
+        ]
+    }
+
+    serializer = serializers.CollectionPageSerializer(conf)
+
+    assert serializer.data == expected