refactor: Centralize API base URL and clean up

Replaces hardcoded Google API base URLs with `settings.BASE_URL` for improved configurability and maintainability across services.

Removes unused imports and variables from various modules to reduce code bloat and enhance readability.

app/service/chat/gemini_chat_service.py

@@ -41,7 +41,7 @@ def _extract_file_references(contents: List[Dict[str, Any]]) -> List[str]:
                 file_uri = file_data["fileUri"]
                 # 從 URI 中提取文件名
                 # 1. https://generativelanguage.googleapis.com/v1beta/files/{file_id}
-                match = re.match(r"https://generativelanguage.googleapis.com/v1beta/(files/.*)", file_uri)
+                match = re.match(rf"{re.escape(settings.BASE_URL)}/(files/.*)", file_uri)
                 if not match:
                     logger.warning(f"Invalid file URI: {file_uri}")
                     continue

app/service/files/file_upload_handler.py

@@ -2,14 +2,13 @@
 文件上传处理器
 处理 Google 的可恢复上传协议
 """
-import hashlib
-from typing import Dict, Any, Optional
+from typing import Optional
 from datetime import datetime, timezone, timedelta
 
 from httpx import AsyncClient
 from fastapi import Request, Response, HTTPException
-from fastapi.responses import StreamingResponse
 
+from app.config.config import settings
 from app.database import services as db_services
 from app.database.models import FileState
 from app.log.logger import get_files_logger
@@ -136,7 +135,7 @@ class FileUploadHandler:
                                     mime_type=file_data.get("mimeType", session_info["mime_type"]),
                                     size_bytes=int(file_data.get("sizeBytes", session_info["size_bytes"])),
                                     api_key=session_info["api_key"],
-                                    uri=file_data.get("uri", f"https://generativelanguage.googleapis.com/v1beta/{real_file_name}"),
+                                    uri=file_data.get("uri", f"{settings.BASE_URL}/{real_file_name}"),
                                     create_time=now,
                                     update_time=now,
                                     expiration_time=datetime.fromisoformat(expiration_time_str),

app/service/files/files_service.py

@@ -2,17 +2,14 @@
 文件管理服务
 """
 import json
-import hashlib
-import uuid
 from datetime import datetime, timedelta, timezone
-from typing import Optional, Dict, Any, Tuple, List
-from httpx import AsyncClient, Headers
-from collections import defaultdict
+from typing import Optional, Dict, Any, Tuple
+from httpx import AsyncClient
 import asyncio
 
 from app.config.config import settings
 from app.database import services as db_services
-from app.database.models import FileRecord, FileState
+from app.database.models import FileState
 from app.domain.file_models import FileMetadata, ListFilesResponse
 from fastapi import HTTPException
 from app.log.logger import get_files_logger
@@ -254,7 +251,7 @@ class FilesService:
             
             async with AsyncClient() as client:
                 response = await client.get(
-                    f"https://generativelanguage.googleapis.com/v1beta/{file_name}",
+                    f"{settings.BASE_URL}/{file_name}",
                     params={"key": api_key}
                 )
                 
@@ -383,7 +380,7 @@ class FilesService:
             
             async with AsyncClient() as client:
                 response = await client.delete(
-                    f"https://generativelanguage.googleapis.com/v1beta/{file_name}",
+                    f"{settings.BASE_URL}/{file_name}",
                     params={"key": api_key}
                 )
                 
@@ -422,7 +419,7 @@ class FilesService:
         try:
             async with AsyncClient() as client:
                 response = await client.get(
-                    f"https://generativelanguage.googleapis.com/v1beta/{file_name}",
+                    f"{settings.BASE_URL}/{file_name}",
                     params={"key": api_key}
                 )
                 
@@ -475,7 +472,7 @@ class FilesService:
                     
                     async with AsyncClient() as client:
                         await client.delete(
-                            f"https://generativelanguage.googleapis.com/v1beta/{file_name}",
+                            f"{settings.BASE_URL}/{file_name}",
                             params={"key": api_key}
                         )
                 except Exception as e: