电子签基础功能

SimpleAdmin.System/Services/Dev/File/FileService.cs

@@ -115,10 +115,26 @@ public class FileService : DbRepository<SysFile>, IFileService
         IFormFile file = new FormFile(stream, 0, content.Length, "file", fileName)
         {
             Headers = new HeaderDictionary(),
-            ContentType = "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
+            ContentType = ResolveGeneratedContentType(fileName)
         };
         return await StorageFile(engine, file);
     }
+
+    /// <summary>
+    /// 根据归档文件扩展名设置 OSS 元数据，避免 PDF、ZIP 被错误标记为 DOCX。
+    /// </summary>
+    private static string ResolveGeneratedContentType(string fileName)
+    {
+        return Path.GetExtension(fileName).ToLowerInvariant() switch
+        {
+            ".docx" => "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
+            ".pdf" => "application/pdf",
+            ".zip" => "application/zip",
+            ".png" => "image/png",
+            ".jpg" or ".jpeg" => "image/jpeg",
+            _ => "application/octet-stream"
+        };
+    }
     #region 方法
 
     /// <summary>