From a9ce45279e74528bf37c337474601499269c2916 Mon Sep 17 00:00:00 2001
From: bymyself <cbyrne@comfy.org>
Date: Thu, 12 Mar 2026 15:17:39 -0700
Subject: [PATCH] fix: use no-store cache headers to prevent stale frontend
 chunks

After a frontend update (e.g. nightly build), browsers could load
outdated cached index.html and JS/CSS chunks, causing dynamically
imported modules to fail with MIME type errors and vite:preloadError.

Hard refresh (Ctrl+Shift+R) was insufficient to fix the issue because
Cache-Control: no-cache still allows the browser to cache and
revalidate via ETags. aiohttp's FileResponse auto-generates ETags
based on file mtime+size, which may not change after pip reinstall,
so the browser gets 304 Not Modified and serves stale content.

Clearing ALL site data in DevTools did fix it, confirming the HTTP
cache was the root cause.

The fix changes:
- index.html: no-cache -> no-store, must-revalidate
- JS/CSS/JSON entry points: no-cache -> no-store

no-store instructs browsers to never cache these responses, ensuring
every page load fetches the current index.html with correct chunk
references. This is a small tradeoff (~5KB re-download per page load)
for guaranteed correctness after updates.
---
 middleware/cache_middleware.py               |  2 +-
 server.py                                    |  2 +-
 tests-unit/server_test/test_cache_control.py | 16 ++++++++--------
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/middleware/cache_middleware.py b/middleware/cache_middleware.py
index f02135369..7a18821b0 100644
--- a/middleware/cache_middleware.py
+++ b/middleware/cache_middleware.py
@@ -32,7 +32,7 @@ async def cache_control(
     )
 
     if request.path.endswith(".js") or request.path.endswith(".css") or is_entry_point:
-        response.headers.setdefault("Cache-Control", "no-cache")
+        response.headers.setdefault("Cache-Control", "no-store")
         return response
 
     # Early return for non-image files - no cache headers needed
diff --git a/server.py b/server.py
index 76904ebc9..85a8964be 100644
--- a/server.py
+++ b/server.py
@@ -310,7 +310,7 @@ class PromptServer():
         @routes.get("/")
         async def get_root(request):
             response = web.FileResponse(os.path.join(self.web_root, "index.html"))
-            response.headers['Cache-Control'] = 'no-cache'
+            response.headers['Cache-Control'] = 'no-store, must-revalidate'
             response.headers["Pragma"] = "no-cache"
             response.headers["Expires"] = "0"
             return response
diff --git a/tests-unit/server_test/test_cache_control.py b/tests-unit/server_test/test_cache_control.py
index fa68d9408..1d0366387 100644
--- a/tests-unit/server_test/test_cache_control.py
+++ b/tests-unit/server_test/test_cache_control.py
@@ -28,31 +28,31 @@ CACHE_SCENARIOS = [
     },
     # JavaScript/CSS scenarios
     {
-        "name": "js_no_cache",
+        "name": "js_no_store",
         "path": "/script.js",
         "status": 200,
-        "expected_cache": "no-cache",
+        "expected_cache": "no-store",
         "should_have_header": True,
     },
     {
-        "name": "css_no_cache",
+        "name": "css_no_store",
         "path": "/styles.css",
         "status": 200,
-        "expected_cache": "no-cache",
+        "expected_cache": "no-store",
         "should_have_header": True,
     },
     {
-        "name": "index_json_no_cache",
+        "name": "index_json_no_store",
         "path": "/api/index.json",
         "status": 200,
-        "expected_cache": "no-cache",
+        "expected_cache": "no-store",
         "should_have_header": True,
     },
     {
-        "name": "localized_index_json_no_cache",
+        "name": "localized_index_json_no_store",
         "path": "/templates/index.zh.json",
         "status": 200,
-        "expected_cache": "no-cache",
+        "expected_cache": "no-store",
         "should_have_header": True,
     },
     # Non-matching files