feat: 初始提交

backend/app/utils/llm_tool.py

@@ -0,0 +1,65 @@
+# -*- coding: utf-8 -*-
+"""OpenAI 兼容型 LLM 工具封装，保持与旧项目一致的接口体验。"""
+
+import os
+from dataclasses import asdict, dataclass
+from typing import AsyncGenerator, Dict, List, Optional
+
+from openai import AsyncOpenAI
+
+
+@dataclass
+class ChatMessage:
+    role: str
+    content: str
+
+    def to_dict(self) -> Dict[str, str]:
+        return asdict(self)
+
+
+class LLMClient:
+    """异步流式调用封装，兼容 OpenAI SDK。"""
+
+    def __init__(self, api_key: Optional[str] = None, base_url: Optional[str] = None):
+        key = api_key or os.environ.get("OPENAI_API_KEY")
+        if not key:
+            raise ValueError("缺少 OPENAI_API_KEY 配置，请在数据库或环境变量中补全。")
+
+        self._client = AsyncOpenAI(api_key=key, base_url=base_url or os.environ.get("OPENAI_API_BASE"))
+
+    async def stream_chat(
+        self,
+        messages: List[ChatMessage],
+        model: Optional[str] = None,
+        response_format: Optional[str] = None,
+        temperature: Optional[float] = None,
+        top_p: Optional[float] = None,
+        max_tokens: Optional[int] = None,
+        timeout: int = 120,
+        **kwargs,
+    ) -> AsyncGenerator[Dict[str, str], None]:
+        payload = {
+            "model": model or os.environ.get("MODEL", "gpt-3.5-turbo"),
+            "messages": [msg.to_dict() for msg in messages],
+            "stream": True,
+            "timeout": timeout,
+            **kwargs,
+        }
+        if response_format:
+            payload["response_format"] = {"type": response_format}
+        if temperature is not None:
+            payload["temperature"] = temperature
+        if top_p is not None:
+            payload["top_p"] = top_p
+        if max_tokens is not None:
+            payload["max_tokens"] = max_tokens
+
+        stream = await self._client.chat.completions.create(**payload)
+        async for chunk in stream:
+            if not chunk.choices:
+                continue
+            choice = chunk.choices[0]
+            yield {
+                "content": choice.delta.content,
+                "finish_reason": choice.finish_reason,
+            }