use aliyun s3 store for this project

app/utils/s3.py

@@ -0,0 +1,53 @@
+import oss2
+import httpx
+import os
+import io
+from fastapi import HTTPException
+
+# 加载配置
+ACCESS_KEY_ID = os.getenv("S3_ACCESS_KEY_ID")
+ACCESS_KEY_SECRET = os.getenv("S3_SECRET_ACCESS_KEY")
+ENDPOINT = os.getenv("S3_ENDPOINT", "https://oss-ap-northeast-1.aliyuncs.com")
+BUCKET_NAME = os.getenv("S3_STORAGE_BUCKET_NAME", "character-roleplay-dev-asset")
+
+# 初始化阿里云 Auth 和 Bucket
+auth = oss2.Auth(ACCESS_KEY_ID, ACCESS_KEY_SECRET)
+bucket = oss2.Bucket(auth, ENDPOINT, BUCKET_NAME)
+
+async def upload_google_avatar_to_s3(google_avatar_url: str, user_id: str) -> str:
+    """
+    下载 Google 头像并上传到阿里云 OSS
+    """
+    try:
+        # 1. 使用 httpx 下载图片
+        async with httpx.AsyncClient(timeout=10.0) as client:
+            response = await client.get(google_avatar_url)
+            if response.status_code != 200:
+                return google_avatar_url
+            
+            image_data = response.content
+            # 获取内容类型（如 image/jpeg）
+            content_type = response.headers.get("Content-Type", "image/jpeg")
+
+        # 构造 OSS 中的存储路径
+        object_name = f"avatars/{user_id}/avatar.jpg"
+
+        headers = {"Content-Type": content_type}
+        
+        # oss2.Bucket.put_object 是同步阻塞调用
+        # 在高并发下建议使用 run_in_executor，初期可以直接这样写
+        bucket.put_object(object_name, image_data, headers=headers)
+
+        # 4. 生成公开访问的 URL
+        # 阿里云 OSS 标准 URL 格式: https://bucket-name.endpoint/object-name
+        # 例如: https://character-roleplay-dev-asset.oss-ap-northeast-1.aliyuncs.com/avatars/xxx/avatar.jpg
+        host = ENDPOINT.replace("https://", "")
+        oss_url = f"https://{BUCKET_NAME}.{host}/{object_name}"
+        
+        return oss_url
+
+    except Exception as e:
+        # 打印错误日志，生产环境建议使用 logger
+        print(f"OSS Upload Error: {str(e)}")
+        # 降级处理：上传失败则返回原始 Google URL，确保用户能注册成功
+        return google_avatar_url