feat: 图片模型连续对话自动上一次响应作为参考图

close #15

src/api/routes.py

@@ -1,13 +1,17 @@
 """API routes - OpenAI compatible endpoints"""
 from fastapi import APIRouter, Depends, HTTPException
 from fastapi.responses import StreamingResponse, JSONResponse
-from typing import List
+from typing import List, Optional
 import base64
 import re
 import json
+import time
+from urllib.parse import urlparse
+from curl_cffi.requests import AsyncSession
 from ..core.auth import verify_api_key_header
 from ..core.models import ChatCompletionRequest
 from ..services.generation_handler import GenerationHandler, MODEL_CONFIG
+from ..core.logger import debug_logger
 
 router = APIRouter()
 
@@ -21,6 +25,40 @@ def set_generation_handler(handler: GenerationHandler):
     generation_handler = handler
 
 
+async def retrieve_image_data(url: str) -> Optional[bytes]:
+    """
+    智能获取图片数据：
+    1. 优先检查是否为本地 /tmp/ 缓存文件，如果是则直接读取磁盘
+    2. 如果本地不存在或是外部链接，则进行网络下载
+    """
+    # 优先尝试本地读取
+    try:
+        if "/tmp/" in url and generation_handler and generation_handler.file_cache:
+            path = urlparse(url).path
+            filename = path.split("/tmp/")[-1]
+            local_file_path = generation_handler.file_cache.cache_dir / filename
+
+            if local_file_path.exists() and local_file_path.is_file():
+                data = local_file_path.read_bytes()
+                if data:
+                    return data
+    except Exception as e:
+        debug_logger.log_warning(f"[CONTEXT] 本地缓存读取失败: {str(e)}")
+
+    # 回退逻辑：网络下载
+    try:
+        async with AsyncSession() as session:
+            response = await session.get(url, timeout=30, impersonate="chrome110", verify=False)
+            if response.status_code == 200:
+                return response.content
+            else:
+                debug_logger.log_warning(f"[CONTEXT] 图片下载失败，状态码: {response.status_code}")
+    except Exception as e:
+        debug_logger.log_error(f"[CONTEXT] 图片下载异常: {str(e)}")
+
+    return None
+
+
 @router.get("/v1/models")
 async def list_models(api_key: str = Depends(verify_api_key_header)):
     """List available models"""
@@ -92,6 +130,33 @@ async def create_chat_completion(
                     image_bytes = base64.b64decode(image_base64)
                     images.append(image_bytes)
 
+        # 自动参考图：仅对图片模型生效
+        model_config = MODEL_CONFIG.get(request.model)
+
+        if model_config and model_config["type"] == "image" and not images and len(request.messages) > 1:
+            debug_logger.log_info(f"[CONTEXT] 开始查找历史参考图，消息数量: {len(request.messages)}")
+
+            # 如果当前请求没有上传图片，则尝试从历史记录中寻找最近的一张生成图
+            for msg in reversed(request.messages[:-1]):
+                if msg.role == "assistant" and isinstance(msg.content, str):
+                    # 匹配 Markdown 图片格式: ![...](http...)
+                    matches = re.findall(r"!\[.*?\]\((.*?)\)", msg.content)
+                    if matches:
+                        last_image_url = matches[-1]
+
+                        if last_image_url.startswith("http"):
+                            try:
+                                downloaded_bytes = await retrieve_image_data(last_image_url)
+                                if downloaded_bytes and len(downloaded_bytes) > 0:
+                                    images.append(downloaded_bytes)
+                                    debug_logger.log_info(f"[CONTEXT] ✅ 自动使用历史参考图: {last_image_url}")
+                                    break
+                                else:
+                                    debug_logger.log_warning(f"[CONTEXT] 图片下载失败或为空，尝试下一个: {last_image_url}")
+                            except Exception as e:
+                                debug_logger.log_error(f"[CONTEXT] 处理参考图时出错: {str(e)}")
+                                # 继续尝试下一个图片
+
         if not prompt:
             raise HTTPException(status_code=400, detail="Prompt cannot be empty")