Initial commit: PastPaper Master full stack

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/services/llm_clients.py

@@ -0,0 +1,74 @@
+import httpx
+from openai import OpenAI
+from app.config import get_settings
+
+_TIMEOUT = httpx.Timeout(connect=10, read=300, write=60, pool=10)
+
+_gpt_client: OpenAI | None = None
+_qwen_client: OpenAI | None = None
+_gemini_flash_client: OpenAI | None = None
+_gemini_lite_client: OpenAI | None = None
+_deepseek_client: OpenAI | None = None
+
+
+def get_gpt_client() -> OpenAI:
+    """laozhang API — gpt-4o / gpt-4o-mini"""
+    global _gpt_client
+    if _gpt_client is None:
+        s = get_settings()
+        _gpt_client = OpenAI(
+            base_url=s.laozhang_base_url,
+            api_key=s.laozhang_api_key,
+        )
+    return _gpt_client
+
+
+def get_qwen_client() -> OpenAI:
+    """DashScope — qwen-plus"""
+    global _qwen_client
+    if _qwen_client is None:
+        s = get_settings()
+        _qwen_client = OpenAI(
+            base_url=s.dashscope_base_url,
+            api_key=s.dashscope_api_key,
+        )
+    return _qwen_client
+
+
+def get_vision_client() -> OpenAI:
+    """Google Gemini 官方 API（视觉，用于拆题+OCR）— 部署在新加坡可用"""
+    global _gemini_flash_client
+    if _gemini_flash_client is None:
+        s = get_settings()
+        _gemini_flash_client = OpenAI(
+            base_url="https://generativelanguage.googleapis.com/v1beta/openai/",
+            api_key=s.google_gemini_api_key,
+            timeout=_TIMEOUT,
+        )
+    return _gemini_flash_client
+
+
+def get_gemini_lite_client() -> OpenAI:
+    """laozhang — gemini-3.1-flash-lite-preview（轻量，用于 AI trio）"""
+    global _gemini_lite_client
+    if _gemini_lite_client is None:
+        s = get_settings()
+        _gemini_lite_client = OpenAI(
+            base_url=s.laozhang_base_url,
+            api_key=s.laozhang_api_key,
+            timeout=_TIMEOUT,
+        )
+    return _gemini_lite_client
+
+
+def get_deepseek_client() -> OpenAI:
+    """DeepSeek — deepseek-chat（用于 AI trio）"""
+    global _deepseek_client
+    if _deepseek_client is None:
+        s = get_settings()
+        _deepseek_client = OpenAI(
+            base_url=s.deepseek_base_url,
+            api_key=s.deepseek_api_key,
+            timeout=_TIMEOUT,
+        )
+    return _deepseek_client