improve small image create, add minimal size check

conf/app.php

@@ -3,8 +3,8 @@
  * Config
  */
 $configs = array(
-    'version' => '0.3.5',
-    'releaseDate' => '2024-10-07',
+    'version' => '0.3.6',
+    'releaseDate' => '2024-10-16',
     'showVersion' => false,     //默认不显示版本号和发布日期
 
     'default_timezone' => 'Asia/Hong_Kong',      //timezone, check more: https://www.php.net/manual/en/timezones.asia.php

themes/beauty/controller/SiteController.php

@@ -590,6 +590,7 @@ Class SiteController extends Controller {
     //优先从缓存获取小尺寸的图片
     //增加父目录封面图缓存更新
     //增加图片尺寸类型参数: size
+    //增加缩略图生成失败检查，如果缩略图文件大小小于 5 Kb，则认为生成了无效的图片（如黑图）
     public function actionSmallimg() {
         $imgId = $this->get('id', '');
         $imgUrl = $this->get('url', '');
@@ -605,6 +606,17 @@ Class SiteController extends Controller {
 
         $small_image_client_cache_seconds = FSC::$app['config']['small_image_client_cache_seconds'];
 
+        //检查文件大小，如果小于 5 Kb，则重新生成图片
+        if (!empty($cachedData)) {
+            $imgType = preg_replace('/^data:(image\/.+);base64,.+$/i', "$1", $cachedData);
+            $base64_img = preg_replace('/^data:image\/.+;base64,/i', '', $cachedData);
+            $img_data = base64_decode($base64_img);
+            $minNormalImgSize = 5 * 1024;       //最小图片尺寸：5Kb
+            if (strlen($img_data) < $minNormalImgSize) {
+                $cachedData = null;
+            }
+        }
+
         //无缓存，则实时生成缩略图
         if (empty($cachedData)) {
             $tmpUrl = parse_url($imgUrl);
@@ -629,7 +641,6 @@ Class SiteController extends Controller {
             $base64_img = preg_replace('/^data:image\/.+;base64,/i', '', $cachedData);
 
             $img_data = base64_decode($base64_img);
-
             $etag = md5($img_data);
             $etag_from_client = !empty($_SERVER['HTTP_IF_NONE_MATCH']) ? $_SERVER['HTTP_IF_NONE_MATCH'] : '';  //get etag from client
             if (!empty($etag) && $etag == $etag_from_client) {