fix: respect json structure while truncating tool call strings

Author: zly2006

packages/global/common/string/tools.ts

@@ -187,7 +187,66 @@ export const sliceStrStartEnd = (str: string, start: number, end: number) => {
   return `${startContent}${overSize ? `\n\n...[hide ${str.length - start - end} chars]...\n\n` : ''}${endContent}`;
 };
 
-/* 
+/**
+ * Slice string while respecting JSON structure
+ */
+export const truncateStrRespectingJson = (str: string, start: number, end: number) => {
+  const overSize = str.length > start + end;
+
+  if (!overSize) return str;
+
+  let obj: any;
+  try {
+    obj = JSON.parse(str);
+  } catch (e) {
+    // Not a valid JSON, fallback to normal slicing
+    return sliceStrStartEnd(str, start, end);
+  }
+
+  let tooLongStrings = 0;
+
+  function forEachString(obj: any, operation: (s: string) => string): any {
+    if (typeof obj === 'string') {
+      return operation(obj);
+    } else if (Array.isArray(obj)) {
+      return obj.map((item) => forEachString(item, operation));
+    } else if (typeof obj === 'object' && obj) {
+      const newObj: any = {};
+      for (const key in obj) {
+        newObj[key] = forEachString(obj[key], operation);
+      }
+      return newObj;
+    }
+    return obj;
+  }
+
+  forEachString(obj, (s) => {
+    if (s.length > 200) {
+      tooLongStrings++;
+      return s;
+    }
+    return s;
+  });
+
+  if (tooLongStrings === 0) {
+    return str;
+  }
+
+  forEachString(obj, (s) => {
+    if (s.length > (start + end) / tooLongStrings) {
+      return sliceStrStartEnd(
+        s,
+        Math.floor(start / tooLongStrings),
+        Math.floor(end / tooLongStrings)
+      );
+    }
+    return s;
+  });
+
+  return JSON.stringify(obj);
+};
+
+/*
   Parse file extension from url
   Test：
   1. https://xxx.com/file.pdf?token=123

packages/service/core/workflow/dispatch/ai/agent/toolCall.ts

@@ -16,7 +16,7 @@ import { GPTMessages2Chats } from '@fastgpt/global/core/chat/adapt';
 import type { AIChatItemType } from '@fastgpt/global/core/chat/type';
 import { formatToolResponse, initToolCallEdges, initToolNodes } from './utils';
 import { computedMaxToken } from '../../../../ai/utils';
-import { sliceStrStartEnd } from '@fastgpt/global/common/string/tools';
+import { truncateStrRespectingJson } from '@fastgpt/global/common/string/tools';
 import type { WorkflowInteractiveResponseType } from '@fastgpt/global/core/workflow/template/system/interactive/type';
 import { ChatItemValueTypeEnum } from '@fastgpt/global/core/chat/constants';
 import { getErrText } from '@fastgpt/global/common/error/utils';
@@ -28,23 +28,23 @@ type ToolRunResponseType = {
   toolMsgParams: ChatCompletionToolMessageParam;
 }[];
 
-/* 
+/*
   调用思路：
   先Check 是否是交互节点触发
-    
+
   交互模式：
   1. 从缓存中获取工作流运行数据
   2. 运行工作流
   3. 检测是否有停止信号或交互响应
     - 无：汇总结果，递归运行工具
     - 有：缓存结果，结束调用
-  
+
   非交互模式：
   1. 组合 tools
   2. 过滤 messages
   3. Load request llm messages: system prompt, histories, human question, （assistant responses, tool responses, assistant responses....)
   4. 请求 LLM 获取结果
-    
+
     - 有工具调用
       1. 批量运行工具的工作流，获取结果（工作流原生结果，工具执行结果）
       2. 合并递归中，所有工具的原生运行结果
@@ -126,7 +126,7 @@ export const runToolCall = async (
           toolName: '',
           toolAvatar: '',
           params: '',
-          response: sliceStrStartEnd(stringToolResponse, 5000, 5000)
+          response: truncateStrRespectingJson(stringToolResponse, 5000, 5000)
         }
       }
     });
@@ -407,7 +407,7 @@ export const runToolCall = async (
             toolName: '',
             toolAvatar: '',
             params: '',
-            response: sliceStrStartEnd(stringToolResponse, 5000, 5000)
+            response: truncateStrRespectingJson(stringToolResponse, 5000, 5000)
           }
         }
       });
@@ -426,7 +426,7 @@ export const runToolCall = async (
             toolName: '',
             toolAvatar: '',
             params: '',
-            response: sliceStrStartEnd(err, 5000, 5000)
+            response: truncateStrRespectingJson(err, 5000, 5000)
           }
         }
       });
@@ -437,7 +437,7 @@ export const runToolCall = async (
           tool_call_id: tool.id,
           role: ChatCompletionRequestMessageRoleEnum.Tool,
           name: tool.function.name,
-          content: sliceStrStartEnd(err, 5000, 5000)
+          content: truncateStrRespectingJson(err, 5000, 5000)
         }
       });
     }
@@ -460,7 +460,7 @@ export const runToolCall = async (
     : usage.outputTokens;
 
   if (toolCalls.length > 0) {
-    /* 
+    /*
       ...
       user
       assistant: tool data
@@ -471,7 +471,7 @@ export const runToolCall = async (
       ...toolsRunResponse.map((item) => item?.toolMsgParams)
     ];
 
-    /* 
+    /*
       Get tool node assistant response
       - history assistant
       - current tool assistant