feat: add content validation

- Add content validation to filter empty or invalid content
- Add special handling for excalidraw clipboard content
- Add minimum content length check
- Add user feedback for invalid content
- Improve error messages

project/llmclipboard/llmclipboard/app.py

@@ -40,6 +40,33 @@ class TextCaptureService:
         )
         self.logger = logging.getLogger(__name__)
 
+    def is_valid_content(self, content):
+        """验证内容是否有效"""
+        if not content:
+            return False
+            
+        # 检查是否是空的JSON对象
+        if content.strip().startswith('{') and content.strip().endswith('}'):
+            try:
+                import json
+                data = json.loads(content)
+                # 检查是否是空的excalidraw内容
+                if data.get('type') == 'excalidraw/clipboard' and not data.get('elements'):
+                    self.logger.info("跳过空的excalidraw内容")
+                    return False
+            except:
+                pass
+                
+        # 检查内容是否全是空白字符
+        if not content.strip():
+            return False
+            
+        # 检查内容是否太短
+        if len(content.strip()) < 5:
+            return False
+            
+        return True
+
     def get_clipboard_content(self):
         """获取剪贴板内容"""
         try:
@@ -50,7 +77,7 @@ class TextCaptureService:
             try:
                 content = win32clipboard.GetClipboardData(win32con.CF_UNICODETEXT)
                 self.logger.info("获取Unicode文本格式内容")
-                if content:
+                if content and self.is_valid_content(content):
                     return content
             except Exception as e:
                 self.logger.debug(f"获取Unicode文本失败: {e}")
@@ -76,7 +103,7 @@ class TextCaptureService:
                         html_content = html_content[start:end+7]
                     
                     content = h.handle(html_content).strip()
-                    if content:
+                    if content and self.is_valid_content(content):
                         return content
             except Exception as e:
                 self.logger.debug(f"获取HTML格式失败: {e}")
@@ -86,18 +113,24 @@ class TextCaptureService:
                 text_content = win32clipboard.GetClipboardData(win32con.CF_TEXT)
                 self.logger.info("获取普通文本格式内容")
                 if text_content:
-                    return text_content.decode('gbk')
+                    content = text_content.decode('gbk')
+                    if self.is_valid_content(content):
+                        return content
             except Exception as e:
                 self.logger.debug(f"获取普通文本失败: {e}")
 
-            if not content:
+            if not content or not self.is_valid_content(content):
-                self.logger.warning("剪贴板内容为空")
+                self.logger.warning("剪贴板内容为空或无效")
+                if hasattr(self, 'gui') and self.gui:
+                    self.gui.show_message("剪贴板内容为空或无效", error=True)
                 return None
 
             return content
 
         except Exception as e:
             self.logger.error(f"获取剪贴板内容失败: {e}")
+            if hasattr(self, 'gui') and self.gui:
+                self.gui.show_message(f"获取剪贴板内容失败: {str(e)}", error=True)
             return None
         finally:
             try: