fix: 修复生成报错

app/services/ai_rewriter.py

@@ -484,6 +484,10 @@ class AIRewriter:
             return json.loads(raw)
         except json.JSONDecodeError:
             pass
+        try:
+            return json.loads(self._escape_control_chars_in_json_string(raw))
+        except json.JSONDecodeError:
+            pass
 
         fenced = re.sub(r"^```(?:json)?\s*|\s*```$", "", raw, flags=re.IGNORECASE).strip()
         if fenced != raw:
@@ -491,14 +495,65 @@ class AIRewriter:
                 return json.loads(fenced)
             except json.JSONDecodeError:
                 pass
+            try:
+                return json.loads(self._escape_control_chars_in_json_string(fenced))
+            except json.JSONDecodeError:
+                pass
 
         start = raw.find("{")
         end = raw.rfind("}")
         if start != -1 and end != -1 and end > start:
-            return json.loads(raw[start : end + 1])
+            sliced = raw[start : end + 1]
+            try:
+                return json.loads(sliced)
+            except json.JSONDecodeError:
+                return json.loads(self._escape_control_chars_in_json_string(sliced))
 
         raise ValueError("model output is not valid JSON")
 
+    def _escape_control_chars_in_json_string(self, s: str) -> str:
+        """
+        修复“近似 JSON”中字符串里的裸控制字符（尤其是换行），
+        避免 `Invalid control character` 导致误判为无效 JSON。
+        """
+        out: list[str] = []
+        in_string = False
+        escaped = False
+        for ch in s:
+            if in_string:
+                if escaped:
+                    out.append(ch)
+                    escaped = False
+                    continue
+                if ch == "\\":
+                    out.append(ch)
+                    escaped = True
+                    continue
+                if ch == '"':
+                    out.append(ch)
+                    in_string = False
+                    continue
+                if ch == "\n":
+                    out.append("\\n")
+                    continue
+                if ch == "\r":
+                    out.append("\\r")
+                    continue
+                if ch == "\t":
+                    out.append("\\t")
+                    continue
+                if ord(ch) < 0x20:
+                    out.append(f"\\u{ord(ch):04x}")
+                    continue
+                out.append(ch)
+                continue
+            else:
+                out.append(ch)
+                if ch == '"':
+                    in_string = True
+                    escaped = False
+        return "".join(out)
+
     def _chat_completions_json(self, user_prompt: str, timeout_sec: float, request_id: str) -> dict | None:
         """chat.completions：通义兼容层在 json_object 下易产出极短 JSON，故 DashScope 不传 response_format，并支持短文自动重试。"""
         max_attempts = 2 if self._prefer_chat_first else 1