fix: 修复工作流模板JSON解析错误

- 添加 WorkflowType 的 From<String> 实现，支持从字符串转换
- 修复 workflow_template_repository 中的JSON字段解析，处理空字符串情况
- 为所有JSON字段（comfyui_workflow_json, ui_config_json, execution_config_json等）添加空字符串检查
- 添加详细的数据库调试测试，帮助诊断JSON解析问题
- 修复 WorkflowTemplateFilter 添加缺失的 search_term 字段

主要修复：
1. JSON解析：当JSON字段为空字符串时，返回空对象而不是解析错误
2. 类型转换：WorkflowType 现在可以从数据库字符串直接转换
3. 错误处理：改进了JSON解析的错误处理逻辑
4. 测试工具：添加了详细的数据库内容检查和逐字段解析测试

这些修复解决了前端 WorkflowList.tsx 中的 'premature end of input' JSON解析错误。

apps/desktop/src-tauri/src/data/repositories/workflow_template_repository.rs

@@ -474,42 +474,65 @@ impl WorkflowTemplateRepository {
 
         // 解析工作流类型
         let type_str: String = row.get("type")?;
-        let workflow_type: WorkflowType = serde_json::from_str(&type_str)
-            .map_err(|e| rusqlite::Error::FromSqlConversionFailure(
-                0, rusqlite::types::Type::Text, Box::new(e)
-            ))?;
+        let workflow_type: WorkflowType = WorkflowType::from(type_str);
 
         let description: Option<String> = row.get("description")?;
 
-        // 解析JSON字段
+        // 解析JSON字段，处理空字符串的情况
         let comfyui_workflow_json_str: String = row.get("comfyui_workflow_json")?;
-        let comfyui_workflow_json: serde_json::Value = serde_json::from_str(&comfyui_workflow_json_str)
+        let comfyui_workflow_json: serde_json::Value = if comfyui_workflow_json_str.trim().is_empty() {
+            serde_json::Value::Object(serde_json::Map::new())
+        } else {
+            serde_json::from_str(&comfyui_workflow_json_str)
                 .map_err(|e| rusqlite::Error::FromSqlConversionFailure(
                     0, rusqlite::types::Type::Text, Box::new(e)
-            ))?;
+                ))?
+        };
 
         let ui_config_json_str: String = row.get("ui_config_json")?;
-        let ui_config_json: serde_json::Value = serde_json::from_str(&ui_config_json_str)
+        let ui_config_json: serde_json::Value = if ui_config_json_str.trim().is_empty() {
+            serde_json::Value::Object(serde_json::Map::new())
+        } else {
+            serde_json::from_str(&ui_config_json_str)
                 .map_err(|e| rusqlite::Error::FromSqlConversionFailure(
                     0, rusqlite::types::Type::Text, Box::new(e)
-            ))?;
+                ))?
+        };
 
         let execution_config_json: Option<serde_json::Value> = row.get::<_, Option<String>>("execution_config_json")?
-            .map(|s| serde_json::from_str(&s))
+            .map(|s| {
+                if s.trim().is_empty() {
+                    Ok(serde_json::Value::Object(serde_json::Map::new()))
+                } else {
+                    serde_json::from_str(&s)
+                }
+            })
             .transpose()
             .map_err(|e| rusqlite::Error::FromSqlConversionFailure(
                 0, rusqlite::types::Type::Text, Box::new(e)
             ))?;
 
         let input_schema_json: Option<serde_json::Value> = row.get::<_, Option<String>>("input_schema_json")?
-            .map(|s| serde_json::from_str(&s))
+            .map(|s| {
+                if s.trim().is_empty() {
+                    Ok(serde_json::Value::Object(serde_json::Map::new()))
+                } else {
+                    serde_json::from_str(&s)
+                }
+            })
             .transpose()
             .map_err(|e| rusqlite::Error::FromSqlConversionFailure(
                 0, rusqlite::types::Type::Text, Box::new(e)
             ))?;
 
         let output_schema_json: Option<serde_json::Value> = row.get::<_, Option<String>>("output_schema_json")?
-            .map(|s| serde_json::from_str(&s))
+            .map(|s| {
+                if s.trim().is_empty() {
+                    Ok(serde_json::Value::Object(serde_json::Map::new()))
+                } else {
+                    serde_json::from_str(&s)
+                }
+            })
             .transpose()
             .map_err(|e| rusqlite::Error::FromSqlConversionFailure(
                 0, rusqlite::types::Type::Text, Box::new(e)

apps/desktop/src-tauri/src/tests/basic_tests.rs

@@ -136,3 +136,171 @@ fn test_json_operations() {
     assert_eq!(json_value["value"], 42);
     assert_eq!(json_value["active"], true);
 }
+
+#[tokio::test]
+async fn test_database_connection() {
+    use crate::infrastructure::database::Database;
+
+    // 测试数据库连接
+    let database = Database::new().expect("应该能够创建数据库连接");
+
+    // 运行迁移
+    database.run_migrations().expect("应该能够运行数据库迁移");
+
+    // 测试查询工作流模板表
+    let conn = database.get_connection();
+    let conn = conn.lock().unwrap();
+
+    // 检查表是否存在
+    let mut stmt = conn.prepare("SELECT name FROM sqlite_master WHERE type='table' AND name='workflow_templates'")
+        .expect("应该能够准备查询语句");
+
+    let table_exists = stmt.exists([]).expect("应该能够检查表是否存在");
+    assert!(table_exists, "workflow_templates 表应该存在");
+
+    // 检查表结构
+    let mut stmt = conn.prepare("PRAGMA table_info(workflow_templates)")
+        .expect("应该能够准备表结构查询");
+
+    let column_count = stmt.query_map([], |row| {
+        Ok(row.get::<_, String>(1)?) // 获取列名
+    }).expect("应该能够查询表结构")
+    .collect::<Result<Vec<_>, _>>()
+    .expect("应该能够收集列信息")
+    .len();
+
+    assert!(column_count > 0, "workflow_templates 表应该有列");
+    println!("数据库连接测试通过，workflow_templates 表有 {} 列", column_count);
+}
+
+#[tokio::test]
+async fn test_workflow_template_repository() {
+    use crate::data::repositories::workflow_template_repository::WorkflowTemplateRepository;
+    use crate::infrastructure::database::Database;
+    use std::sync::Arc;
+
+    // 创建数据库和仓库
+    let database = Arc::new(Database::new().expect("应该能够创建数据库"));
+    database.run_migrations().expect("应该能够运行迁移");
+
+    // 首先检查数据库中的原始数据
+    let conn = database.get_connection();
+    let conn = conn.lock().unwrap();
+
+    // 检查表中是否有数据
+    let count: i64 = conn.query_row("SELECT COUNT(*) FROM workflow_templates", [], |row| {
+        row.get(0)
+    }).expect("应该能够查询记录数量");
+
+    println!("数据库中有 {} 条工作流模板记录", count);
+
+    if count > 0 {
+        // 检查第一条记录的所有字段
+        let mut stmt = conn.prepare("SELECT * FROM workflow_templates LIMIT 1")
+            .expect("应该能够准备查询语句");
+
+        let result = stmt.query_row([], |row| {
+            println!("第一条记录的所有字段:");
+            for i in 0..row.as_ref().column_count() {
+                let column_name = row.as_ref().column_name(i).unwrap_or("unknown");
+                match row.get_ref(i) {
+                    Ok(value) => {
+                        match value {
+                            rusqlite::types::ValueRef::Null => println!("  {}: NULL", column_name),
+                            rusqlite::types::ValueRef::Integer(v) => println!("  {}: {}", column_name, v),
+                            rusqlite::types::ValueRef::Real(v) => println!("  {}: {}", column_name, v),
+                            rusqlite::types::ValueRef::Text(v) => {
+                                let text = std::str::from_utf8(v).unwrap_or("invalid utf8");
+                                if text.len() > 100 {
+                                    println!("  {}: {} chars, preview: {:?}", column_name, text.len(), &text[..100]);
+                                } else {
+                                    println!("  {}: {:?}", column_name, text);
+                                }
+                            },
+                            rusqlite::types::ValueRef::Blob(v) => println!("  {}: blob {} bytes", column_name, v.len()),
+                        }
+                    },
+                    Err(e) => println!("  {}: ERROR - {}", column_name, e),
+                }
+            }
+            Ok(())
+        });
+
+        if let Err(e) = result {
+            println!("查询第一条记录失败: {}", e);
+        }
+    }
+
+    drop(conn); // 释放连接
+
+    // 现在测试手动解析第一条记录
+    if count > 0 {
+        let conn = database.get_connection();
+        let conn = conn.lock().unwrap();
+
+        let mut stmt = conn.prepare("SELECT * FROM workflow_templates LIMIT 1")
+            .expect("应该能够准备查询语句");
+
+        let result = stmt.query_row([], |row| {
+            println!("开始手动解析记录...");
+
+            // 逐个字段解析，找出问题所在
+            let id: Option<i64> = Some(row.get("id")?);
+            println!("✓ ID: {:?}", id);
+
+            let name: String = row.get("name")?;
+            println!("✓ Name: {}", name);
+
+            let base_name: String = row.get("base_name")?;
+            println!("✓ Base name: {}", base_name);
+
+            let version: String = row.get("version")?;
+            println!("✓ Version: {}", version);
+
+            let type_str: String = row.get("type")?;
+            println!("✓ Type: {}", type_str);
+
+            let description: Option<String> = row.get("description")?;
+            println!("✓ Description: {:?}", description);
+
+            // 测试JSON字段解析
+            let comfyui_workflow_json_str: String = row.get("comfyui_workflow_json")?;
+            println!("✓ ComfyUI JSON string length: {}", comfyui_workflow_json_str.len());
+
+            // 尝试解析JSON
+            match serde_json::from_str::<serde_json::Value>(&comfyui_workflow_json_str) {
+                Ok(json) => println!("✓ ComfyUI JSON parsed successfully"),
+                Err(e) => println!("✗ ComfyUI JSON parse error: {}", e),
+            }
+
+            let ui_config_json_str: String = row.get("ui_config_json")?;
+            println!("✓ UI Config JSON string length: {}", ui_config_json_str.len());
+
+            match serde_json::from_str::<serde_json::Value>(&ui_config_json_str) {
+                Ok(json) => println!("✓ UI Config JSON parsed successfully"),
+                Err(e) => println!("✗ UI Config JSON parse error: {}", e),
+            }
+
+            Ok(())
+        });
+
+        if let Err(e) = result {
+            println!("手动解析失败: {}", e);
+        }
+
+        drop(conn);
+    }
+
+    let repo = WorkflowTemplateRepository::new(database);
+
+    // 测试查询所有模板（应该返回空列表而不是错误）
+    match repo.find_all(None) {
+        Ok(templates) => {
+            println!("成功查询工作流模板，数量: {}", templates.len());
+            // 空列表是正常的，因为还没有插入数据
+        },
+        Err(e) => {
+            panic!("查询工作流模板失败: {}", e);
+        }
+    }
+}