Fix streaming analysis None value concatenation error and improve error handling

app.py

@@ -846,8 +846,8 @@ async def streaming_ai_analysis(text: str, keywords: List[str], country: str, la
                                     chunk = json.loads(data_str)
                                     if 'choices' in chunk and len(chunk['choices']) > 0:
                                         delta = chunk['choices'][0].get('delta', {})
-                                        if 'content' in delta:
-                                            yield delta['content']
+                                        if 'content' in delta and delta['content']:
+                                            yield str(delta['content'])
                                 except json.JSONDecodeError:
                                     continue
                 else:
@@ -891,7 +891,8 @@ def comprehensive_text_audit_streaming(text, keywords="", country="China", langu
             while True:
                 try:
                     chunk = loop.run_until_complete(async_gen.__anext__())
-                    accumulated_content += chunk
+                    if chunk:  # 确保chunk不是None
+                        accumulated_content += str(chunk)
 
                     # 实时输出累积内容
                     yield f"""
@@ -994,7 +995,39 @@ def comprehensive_text_audit_streaming(text, keywords="", country="China", langu
 
     except Exception as e:
         print(f"Streaming analysis error: {e}")
-        yield generate_error_card(str(e))
+        error_msg = f"Analysis failed: {str(e)}"
+        yield f"""
+        <div style="
+            max-width: 900px;
+            margin: 0 auto;
+            padding: 30px;
+            background: linear-gradient(135deg, #E8E3DE 0%, #F2EDE9 100%);
+            border-radius: 20px;
+            font-family: 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
+        ">
+            <div style="
+                background-color: #F2EDE9;
+                border-radius: 15px;
+                padding: 25px;
+                box-shadow: 0 10px 30px rgba(0,0,0,0.1);
+                text-align: center;
+            ">
+                <h2 style="color: #B85450; margin-bottom: 15px; font-size: 24px;">⚠️ Analysis Error</h2>
+                <p style="color: #5B5B5B; margin-bottom: 20px; font-size: 16px;">AI analysis encountered an issue:</p>
+                <div style="
+                    background-color: rgba(184, 84, 80, 0.1);
+                    padding: 15px;
+                    border-radius: 10px;
+                    border-left: 4px solid #B85450;
+                    text-align: left;
+                    margin-bottom: 20px;
+                ">
+                    <code style="color: #B85450; font-size: 14px;">{error_msg}</code>
+                </div>
+                <p style="color: #8C8C8C; font-size: 14px;">Please try again later or check your network connection</p>
+            </div>
+        </div>
+        """
 
 # 更新审核函数以支持新参数
 def comprehensive_text_audit_with_options(text, keywords="", country="中国", language="简体中文"):