Re-fetch QR codes after 12 hours

php/utils/room-icons.php

@@ -58,7 +58,7 @@
             log_debug("Fetching icon for $room_id.");
             $icon = file_get_contents($icon_url);
             if (empty($icon)) {
-                log_info("$room_id returned empty icon.");
+                log_info("$room_id returned an empty icon.");
             }
             // Never overwrite with an empty file.
             if (!(file_exists($icon_cached) && filesize($icon_cached) > 0 && empty($icon))) {

php/utils/room-invites.php

@@ -26,15 +26,20 @@
 	function room_qr_code($room): string {
 		$room_id = $room->get_room_identifier();
 		$png_cached = room_qr_code_path($room_id);
-		if (file_exists($png_cached)) {
+		$image_expired = file_exists($png_cached) && 
+			filemtime($png_cached) < strtotime("-12 hour");
+		if (file_exists($png_cached) && !$image_expired) {
 			return room_qr_code_path_relative($room_id);
 		}
 		log_debug("Fetching QR code for $room_id.");
 		$png = file_get_contents($room->get_invite_url());
 		if (empty($png)) {
-			log_warning("$room_id returned empty QR code.");
+			log_warning("$room_id returned an empty QR code.");
+		}
+		// Never overwrite with an empty file.
+		if (!(file_exists($png_cached) && filesize($png_cached) > 0 && empty($png))) {
+			file_put_contents($png_cached, $png);
 		}
-		file_put_contents($png_cached, $png);
 		return room_qr_code_path_relative($room_id);
 	}