Makes attachment Images a serializable class

bookwyrm/migrations/0014_auto_20201128_0118.py

@@ -0,0 +1,17 @@
+# Generated by Django 3.0.7 on 2020-11-28 01:18
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('bookwyrm', '0013_book_origin_id'),
+    ]
+
+    operations = [
+        migrations.RenameModel(
+            old_name='Attachment',
+            new_name='Image',
+        ),
+    ]

bookwyrm/models/__init__.py

@@ -5,15 +5,21 @@ import sys
 from .book import Book, Work, Edition
 from .author import Author
 from .connector import Connector
-from .relationship import UserFollows, UserFollowRequest, UserBlocks
+
 from .shelf import Shelf, ShelfBook
+
 from .status import Status, GeneratedNote, Review, Comment, Quotation
-from .status import Attachment, Favorite, Boost, Notification, ReadThrough
+from .status import Favorite, Boost, Notification, ReadThrough
+from .attachment import Image
+
 from .tag import Tag
+
 from .user import User
+from .relationship import UserFollows, UserFollowRequest, UserBlocks
 from .federated_server import FederatedServer
 
 from .import_job import ImportJob, ImportItem
+
 from .site import SiteSettings, SiteInvite, PasswordReset
 
 cls_members = inspect.getmembers(sys.modules[__name__], inspect.isclass)

bookwyrm/models/attachment.py

@@ -0,0 +1,31 @@
+''' media that is posted in the app '''
+from django.db import models
+
+from bookwyrm import activitypub
+from .base_model import ActivitypubMixin
+from .base_model import ActivityMapping, BookWyrmModel
+
+
+class Attachment(ActivitypubMixin, BookWyrmModel):
+    ''' an image (or, in the future, video etc) associated with a status '''
+    status = models.ForeignKey(
+        'Status',
+        on_delete=models.CASCADE,
+        related_name='attachments'
+    )
+    class Meta:
+        ''' one day we'll have other types of attachments besides images '''
+        abstract = True
+
+    activity_mappings = [
+        ActivityMapping('id', 'remote_id'),
+        ActivityMapping('url', 'image'),
+        ActivityMapping('name', 'caption'),
+    ]
+
+class Image(Attachment):
+    ''' an image attachment '''
+    image = models.ImageField(upload_to='status/', null=True, blank=True)
+    caption = models.TextField(null=True, blank=True)
+
+    activity_serializer = activitypub.Image

bookwyrm/models/status.py

@@ -151,17 +151,6 @@ class Status(OrderedCollectionPageMixin, BookWyrmModel):
         return super().save(*args, **kwargs)
 
 
-class Attachment(BookWyrmModel):
-    ''' an image (or, in the future, video etc) associated with a status '''
-    status = models.ForeignKey(
-        'Status',
-        on_delete=models.CASCADE,
-        related_name='attachments'
-    )
-    image = models.ImageField(upload_to='status/', null=True, blank=True)
-    caption = models.TextField(null=True, blank=True)
-
-
 class GeneratedNote(Status):
     ''' these are app-generated messages about user activity '''
     @property