perf(prompts): make /tags fetch only the tags column with SQL access filter (#24287)

Non-admin GET /api/v1/prompts/tags went through get_prompts_by_user_id,
which loaded every active prompt with its full content/data/meta plus
owner records and all access grants, then ran one has_access query per
prompt that wasn't owned by the caller - all so the endpoint could
collapse the result to a sorted tag list. With 600 prompts this took
several seconds while the admin path (a single SELECT) returned in <1s.

Add Prompts.get_tags_by_user_id which selects only the tags column and
applies the same EXISTS-based access filter used by /list. Also tighten
the admin get_tags to project just the tags column instead of full rows.
The endpoint is now one DB query (plus one for groups), no row hydration,
no N+1.

Co-authored-by: Claude <noreply@anthropic.com>

backend/open_webui/models/prompts.py

@@ -663,12 +663,38 @@ class PromptsTable:
     async def get_tags(self, db: Optional[AsyncSession] = None) -> list[str]:
         try:
             async with get_async_db_context(db) as db:
-                result = await db.execute(select(Prompt).filter_by(is_active=True))
-                prompts = result.scalars().all()
+                result = await db.execute(select(Prompt.tags).filter(Prompt.is_active == True))
                 tags = set()
-                for prompt in prompts:
-                    if prompt.tags:
-                        for tag in prompt.tags:
+                for (tag_list,) in result.all():
+                    if tag_list:
+                        for tag in tag_list:
+                            if tag:
+                                tags.add(tag)
+                return sorted(list(tags))
+        except Exception:
+            return []
+
+    async def get_tags_by_user_id(self, user_id: str, db: Optional[AsyncSession] = None) -> list[str]:
+        try:
+            async with get_async_db_context(db) as db:
+                user_groups = await Groups.get_groups_by_member_id(user_id, db=db)
+                user_group_ids = [group.id for group in user_groups]
+
+                query = select(Prompt.tags).filter(Prompt.is_active == True)
+                query = AccessGrants.has_permission_filter(
+                    db=db,
+                    query=query,
+                    DocumentModel=Prompt,
+                    filter={'user_id': user_id, 'group_ids': user_group_ids},
+                    resource_type='prompt',
+                    permission='read',
+                )
+
+                result = await db.execute(query)
+                tags = set()
+                for (tag_list,) in result.all():
+                    if tag_list:
+                        for tag in tag_list:
                             if tag:
                                 tags.add(tag)
                 return sorted(list(tags))

backend/open_webui/routers/prompts.py

@@ -61,13 +61,7 @@ async def get_prompts(user=Depends(get_verified_user), db: AsyncSession = Depend
 async def get_prompt_tags(user=Depends(get_verified_user), db: AsyncSession = Depends(get_async_session)):
     if user.role == 'admin' and BYPASS_ADMIN_ACCESS_CONTROL:
         return await Prompts.get_tags(db=db)
-    else:
-        prompts = await Prompts.get_prompts_by_user_id(user.id, 'read', db=db)
-        tags = set()
-        for prompt in prompts:
-            if prompt.tags:
-                tags.update(prompt.tags)
-        return sorted(list(tags))
+    return await Prompts.get_tags_by_user_id(user.id, db=db)
 
 
 @router.get('/list', response_model=PromptAccessListResponse)