feat(backend): CivitAI download support for other model types with subtype routing

py/routes/handlers/download_routing_handlers.py

@@ -7,7 +7,11 @@ import logging
 
 from aiohttp import web
 
-from ...services.download_routing import is_diffusion_model_download
+from ...services.download_routing import (
+    is_diffusion_model_download,
+    resolve_other_download_sub_type,
+)
+from ...utils.constants import VALID_OTHER_CIVITAI_TYPES
 
 logger = logging.getLogger(__name__)
 
@@ -31,6 +35,7 @@ class DownloadRoutingHandler:
         model_type = payload.get("model_type", "")
         base_model = payload.get("base_model") or ""
         file_types = payload.get("file_types") or []
+        selected_file_type = payload.get("selected_file_type")
 
         if not isinstance(model_type, str) or not model_type:
             return web.json_response(
@@ -44,6 +49,25 @@ class DownloadRoutingHandler:
                 },
                 status=400,
             )
+        if selected_file_type is not None and not isinstance(selected_file_type, str):
+            return web.json_response(
+                {"success": False, "error": "selected_file_type must be a string"},
+                status=400,
+            )
+
+        if model_type.lower() in VALID_OTHER_CIVITAI_TYPES:
+            sub_type = resolve_other_download_sub_type(
+                model_type,
+                file_types=(str(t) for t in file_types),
+                selected_file_type=selected_file_type,
+            )
+            return web.json_response(
+                {
+                    "success": True,
+                    "root_kind": "other",
+                    "sub_type": sub_type,
+                }
+            )
 
         is_diffusion = is_diffusion_model_download(
             model_type,