Make max_media_attachments configurable by admin (#669)

api/views/instance.py

@@ -41,7 +41,7 @@ def instance_info_v1(request):
             "accounts": {},
             "statuses": {
                 "max_characters": Config.system.post_length,
-                "max_media_attachments": 4,
+                "max_media_attachments": Config.system.max_media_attachments,
                 "characters_reserved_per_url": 23,
             },
             "media_attachments": {
@@ -102,7 +102,7 @@ def instance_info_v2(request) -> dict:
             "accounts": {"max_featured_tags": 0},
             "statuses": {
                 "max_characters": Config.system.post_length,
-                "max_media_attachments": 4,
+                "max_media_attachments": Config.system.max_media_attachments,
                 "characters_reserved_per_url": 23,
             },
             "media_attachments": {

core/models/config.py

@@ -214,6 +214,7 @@ class Config(models.Model):
         content_warning_text: str = "Content Warning"
 
         post_length: int = 500
+        max_media_attachments: int = 4
         post_minimum_interval: int = 3  # seconds
         identity_min_length: int = 2
         identity_max_per_user: int = 5

users/views/admin/settings.py

@@ -38,6 +38,10 @@ class BasicSettings(AdminSettingsPage):
             "title": "Maximum Post Length",
             "help_text": "The maximum number of characters allowed per post",
         },
+        "max_media_attachments": {
+            "title": "Maximum Media Attachments",
+            "help_text": "The maximum number of media attachments allowed per post.\nA value other than 4 may be unsupported by clients.",
+        },
         "post_minimum_interval": {
             "title": "Minimum Posting Interval",
             "help_text": "The minimum number of seconds a user must wait between posts",
@@ -129,6 +133,7 @@ class BasicSettings(AdminSettingsPage):
         ],
         "Posts": [
             "post_length",
+            "max_media_attachments",
             "post_minimum_interval",
             "content_warning_text",
             "hashtag_unreviewed_are_public",