Don't send data if not modified

blueprints/risdeveau/__init__.py

@@ -4,9 +4,12 @@ from pathlib import Path
 from htmlmin import minify
 from time import time
 from datetime import datetime, timedelta
+from hashlib import md5
+from json import dumps
 from musicbrainzngs import get_image_front
 from flask import (
     Blueprint,
+    request,
     render_template,
     send_file,
     send_from_directory,
@@ -40,6 +43,12 @@ def utmsmp(unix: int) -> str:
 def rtmsmp(unix: int) -> str:
     return tmsmp(int(time() - unix))
 
+def lb_etag():
+    return md5((dumps(listens.get('data')) + dumps(listening.get('data'))).encode()).hexdigest()
+
+def steam_etag():
+    return md5((dumps(recent.get('data')) + dumps(owned.get('data'))).encode()).hexdigest()
+
 bp = Blueprint(
     "risdeveau",
     __name__,
@@ -73,6 +82,8 @@ def mb_cover(mbid):
     return r
 
 args = {
+    "lb_etag": lb_etag,
+    "steam_etag": steam_etag,
     "lb":     listens,
     "lb_now": listening,
     "recent": recent,
@@ -88,4 +99,22 @@ def index():
 
 @bp.route("/m/<module>")
 def module(module):
+    if modified_since := request.headers.get('if-modified-since'):
+        modified_since = int(modified_since)
+    none_match = request.headers.get('if-none-match')
+
+    if any((modified_since, none_match)):
+        match module:
+            case "listenbrainz":
+                if modified_since >= int(max((x.get('last_updated', 0) for x in (listens, listening)))):
+                    return '', 304
+                if none_match == lb_etag():
+                    return '', 304
+
+            case "steam":
+                if modified_since >= int(max((x.get('last_updated', 0) for x in (recent, owned)))):
+                    return "Not updated yet", 304
+                if none_match == steam_etag():
+                    return '', 304
+
     return render_tmpl(f'{module}.htm', **args)