Disable caching of index.html

Fixes: https://github.com/aquarist-labs/s3gw/issues/730

Signed-off-by: Volker Theile <[email protected]>

src/frontend/src/index.html

@@ -4,9 +4,6 @@
   <meta charset="utf-8">
   <title></title>
   <meta name="viewport" content="width=device-width, initial-scale=1">
-  <meta http-equiv="cache-control" content="no-cache">
-  <meta http-equiv="pragma" content="no-cache">
-  <meta http-equiv="expires" content="0">
   <link rel="icon" type="image/x-icon" href="favicon.ico">
   <link rel="apple-touch-icon" href="favicon_180x180.png">
   <link rel="icon" href="favicon.svg" sizes="any" type="image/svg+xml">

src/s3gw_ui_backend.py

@@ -19,15 +19,30 @@
 from typing import Awaitable, Callable
 
 import uvicorn
-from fastapi import FastAPI
+from fastapi import FastAPI, Response
 from fastapi.logger import logger
 from fastapi.staticfiles import StaticFiles
+from starlette.types import Scope
 
 from backend.api import admin, auth, buckets, config, objects
 from backend.config import Config
 from backend.logging import setup_logging
 
 
+class S3gwStaticFiles(StaticFiles):
+    async def get_response(self, path: str, scope: Scope) -> Response:
+        resp = await super().get_response(path, scope)
+        if scope["path"] == "/":  # index.html
+            resp.headers.update(
+                {
+                    "Cache-Control": "no-cache, max-age=0, must-revalidate",
+                    "Expires": "0",
+                    "Pragma": "no-cache",
+                }
+            )
+        return resp
+
+
 async def s3gw_startup(s3gw_app: FastAPI, s3gw_api: FastAPI) -> None:
     setup_logging()
     logger.info("Starting s3gw-ui backend")
@@ -90,7 +105,9 @@ async def on_shutdown():  # type: ignore
     s3gw_app.mount("/api", s3gw_api, name="api")
     if static_dir is not None:
         s3gw_app.mount(
-            "/", StaticFiles(directory=static_dir, html=True), name="static"
+            "/",
+            S3gwStaticFiles(directory=static_dir, html=True),
+            name="static",
         )
 
     return s3gw_app