Server: If-Modified-Since, block bis Änderung; Client: sofortiger Re-Poll

server.py

@@ -8,6 +8,7 @@ import http.server
 import socketserver
 import urllib.request
 import urllib.parse
+import urllib.error
 import sys
 import os
 import threading
@@ -31,28 +32,33 @@ last_standings_fetch_time = None
 
 
 def fetch_pgn():
-    """Lädt die PGN-Datei von der URL als Bytes."""
+    """Lädt die PGN-Datei von der URL als Bytes.
+    Nutzt If-Modified-Since – gibt (data, changed) zurück.
+    changed=False bedeutet 304 Not Modified (keine neuen Daten)."""
     global last_fetch_time
     try:
         headers = {"User-Agent": "Mozilla/5.0"}
         if last_fetch_time:
-            headers["modified_since"] = str(last_fetch_time)
+            headers["If-Modified-Since"] = datetime.utcfromtimestamp(last_fetch_time).strftime("%a, %d %b %Y %H:%M:%S GMT")
         req = urllib.request.Request(PGN_URL, headers=headers)
         with urllib.request.urlopen(req, timeout=31) as response:
             data = response.read()
             last_fetch_time = time.time()
-            return data
+            return data, True
+    except urllib.error.HTTPError as e:
+        if e.code == 304:
+            return None, False
+        print(f"[{datetime.now().strftime('%H:%M:%S')}] HTTP-Fehler: {e}")
+        return None, False
     except Exception as e:
         print(f"[{datetime.now().strftime('%H:%M:%S')}] Fehler beim Laden: {e}")
-        return None
+        return None, False
 
 
 def get_pgn_content_longpoll(since=0):
-    """Long-Poll: Gibt PGN-Inhalt + mtime zurück.
-    Wenn Cache seit `since` unverändert ist, wird bis zu 31s gewartet."""
-    deadline = time.time() + 31
-
-    while time.time() < deadline:
+    """Long-Poll: Blockiert, bis sich die PGN-Datei tatsächlich ändert.
+    Antwortet nur bei neuen Daten, nie mit unverändertem Stand."""
+    while True:
         if os.path.exists(CACHE_FILE):
             mtime = os.path.getmtime(CACHE_FILE)
             if mtime > since:
@@ -60,28 +66,21 @@ def get_pgn_content_longpoll(since=0):
                     return f.read(), mtime
             age = time.time() - mtime
             if age >= CACHE_TTL:
-                content = fetch_pgn()
-                if content:
+                content, changed = fetch_pgn()
+                if changed and content is not None:
                     with open(CACHE_FILE, "wb") as f:
                         f.write(content)
                     new_mtime = os.path.getmtime(CACHE_FILE)
-                    if new_mtime > since:
-                        print(f"[{datetime.now().strftime('%H:%M:%S')}] PGN via Long-Poll aktualisiert ({len(content)} Bytes)")
-                        return content, new_mtime
+                    print(f"[{datetime.now().strftime('%H:%M:%S')}] PGN via Long-Poll aktualisiert ({len(content)} Bytes)")
+                    return content, new_mtime
         else:
-            content = fetch_pgn()
-            if content:
+            content, changed = fetch_pgn()
+            if changed and content is not None:
                 with open(CACHE_FILE, "wb") as f:
                     f.write(content)
                 return content, os.path.getmtime(CACHE_FILE)
 
-        time.sleep(2)
-
-    # Timeout – aktuellen Stand zurückgeben
-    if os.path.exists(CACHE_FILE):
-        with open(CACHE_FILE, "rb") as f:
-            return f.read(), os.path.getmtime(CACHE_FILE)
-    return None, 0
+        time.sleep(5)
 
 
 def fetch_standings():