[BugFix] fix mm_positions type error (#5182)

* fix mm_positions type error

* update code

* update code

* update code

---------

Co-authored-by: Jiang-Jia-Jun <163579578+Jiang-Jia-Jun@users.noreply.github.com>

fastdeploy/engine/request.py

@@ -17,6 +17,7 @@
 from __future__ import annotations
 
 import time
+import traceback
 from dataclasses import asdict, dataclass, fields
 from enum import Enum
 from typing import Any, Dict, Generic, Optional, Union
@@ -24,7 +25,6 @@ from typing import Any, Dict, Generic, Optional, Union
 import numpy as np
 from typing_extensions import TypeVar
 
-from fastdeploy import envs
 from fastdeploy.engine.pooling_params import PoolingParams
 from fastdeploy.engine.sampling_params import SamplingParams
 from fastdeploy.entrypoints.openai.protocol import ToolCall
@@ -190,6 +190,22 @@ class Request:
             pooling_params = PoolingParams.from_dict(d["pooling_params"])
         else:
             sampling_params = SamplingParams.from_dict(d)
+        if (
+            isinstance(d.get("multimodal_inputs"), dict)
+            and isinstance(d["multimodal_inputs"].get("mm_positions"), list)
+            and len(d["multimodal_inputs"]["mm_positions"]) > 0
+        ):
+            # if mm_positions is not of type ImagePosition, convert to ImagePosition
+            try:
+                for i, mm_pos in enumerate(d["multimodal_inputs"]["mm_positions"]):
+                    d["multimodal_inputs"]["mm_positions"][i] = (
+                        ImagePosition(**mm_pos) if not isinstance(mm_pos, ImagePosition) else mm_pos
+                    )
+            except Exception as e:
+                data_processor_logger.error(
+                    f"Convert mm_positions to ImagePosition error: {e}, {str(traceback.format_exc())}"
+                )
+
         return cls(
             request_id=d["request_id"],
             prompt=d.get("prompt"),