See #170: proper error handling for username uniqueness in channels

api/funkwhale_api/audio/serializers.py

@@ -6,6 +6,7 @@ from funkwhale_api.common import serializers as common_serializers
 from funkwhale_api.common import utils as common_utils
 from funkwhale_api.common import locales
 from funkwhale_api.common import preferences
+from funkwhale_api.federation import models as federation_models
 from funkwhale_api.federation import serializers as federation_serializers
 from funkwhale_api.federation import utils as federation_utils
 from funkwhale_api.music import models as music_models
@@ -74,6 +75,14 @@ class ChannelCreateSerializer(serializers.Serializer):
         validated_data["metadata"] = metadata
         return validated_data
 
+    def validate_username(self, value):
+        matching = federation_models.Actor.objects.local().filter(
+            preferred_username__iexact=value
+        )
+        if matching.exists():
+            raise serializers.ValidationError("This username is already taken")
+        return value
+
     @transaction.atomic
     def create(self, validated_data):
         from . import views

api/tests/audio/test_serializers.py

@@ -56,7 +56,6 @@ def test_channel_serializer_create_honor_max_channels_setting(factories, prefere
     attributed_to = factories["federation.Actor"](local=True)
     factories["audio.Channel"](attributed_to=attributed_to)
     data = {
-        # TODO: cover
         "name": "My channel",
         "username": "mychannel",
         "description": {"text": "This is my channel", "content_type": "text/markdown"},
@@ -71,6 +70,23 @@ def test_channel_serializer_create_honor_max_channels_setting(factories, prefere
         assert serializer.is_valid(raise_exception=True)
 
 
+def test_channel_serializer_create_validates_username(factories):
+    attributed_to = factories["federation.Actor"](local=True)
+    data = {
+        "name": "My channel",
+        "username": attributed_to.preferred_username.upper(),
+        "description": {"text": "This is my channel", "content_type": "text/markdown"},
+        "tags": ["hello", "world"],
+        "content_category": "other",
+    }
+
+    serializer = serializers.ChannelCreateSerializer(
+        data=data, context={"actor": attributed_to}
+    )
+    with pytest.raises(serializers.serializers.ValidationError, match=r".*username.*"):
+        assert serializer.is_valid(raise_exception=True)
+
+
 def test_channel_serializer_create_podcast(factories):
     attributed_to = factories["federation.Actor"](local=True)