Invalidate CSS cache when updated

app/config.py

@@ -1,3 +1,4 @@
+import hashlib
 import os
 import secrets
 from pathlib import Path
@@ -25,6 +26,14 @@ try:
 except ImportError:
     pass
 
+# Force reloading cache when the CSS is updated
+CSS_HASH = "none"
+try:
+    css_data = (ROOT_DIR / "app" / "static" / "css" / "main.css").read_bytes()
+    CSS_HASH = hashlib.md5(css_data, usedforsecurity=False).hexdigest()
+except FileNotFoundError:
+    pass
+
 
 VERSION = f"2.0.0+{VERSION_COMMIT}"
 USER_AGENT = f"microblogpub/{VERSION}"

app/templates.py

@@ -26,6 +26,7 @@ from app.actor import LOCAL_ACTOR
 from app.ap_object import Attachment
 from app.ap_object import Object
 from app.config import BASE_URL
+from app.config import CSS_HASH
 from app.config import DEBUG
 from app.config import VERSION
 from app.config import generate_csrf_token
@@ -102,6 +103,7 @@ async def render_template(
             "request": request,
             "debug": DEBUG,
             "microblogpub_version": VERSION,
+            "css_hash": CSS_HASH,
             "is_admin": is_admin,
             "csrf_token": generate_csrf_token(),
             "highlight_css": HIGHLIGHT_CSS,

app/templates/layout.html

@@ -4,7 +4,7 @@
 <meta charset="utf-8">
 <meta http-equiv="x-ua-compatible" content="ie=edge">
 <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
-<link rel="stylesheet" href="/static/css/main.css">
+<link rel="stylesheet" href="/static/css/main.css?v={{ css_hash }}">
 <link rel="alternate" title="{{ local_actor.display_name}}'s microblog" type="application/json" href="{{ url_for("json_feed") }}" />
 <link rel="alternate" href="{{ url_for("rss_feed") }}" type="application/rss+xml" title="{{ local_actor.display_name}}'s microblog">
 <link rel="alternate" href="{{ url_for("atom_feed") }}" type="application/atom+xml" title="{{ local_actor.display_name}}'s microblog">