feat: 初始化项目，并且接近完成 ozon 部分

server/services/storage.py

@@ -0,0 +1,70 @@
+"""本地文件存储：落 data/media/，由 FastAPI /media 静态托管。"""
+from __future__ import annotations
+
+import mimetypes
+import uuid
+from pathlib import Path
+
+import httpx
+
+from config import get_settings
+
+
+def media_root() -> Path:
+    root = Path(get_settings().data_dir) / "media"
+    root.mkdir(parents=True, exist_ok=True)
+    return root
+
+
+def public_url(key: str) -> str:
+    """media key → 可访问 URL。"""
+    settings = get_settings()
+    return f"{settings.app_base_url.rstrip('/')}/media/{key}"
+
+
+def _ext_from_url_or_type(hint: str, content_type: str = "") -> str:
+    if content_type:
+        ctype = content_type.split(";")[0].strip().lower()
+        mapping = {
+            "image/jpeg": ".jpg", "image/png": ".png", "image/webp": ".webp",
+            "image/gif": ".gif", "image/bmp": ".bmp", "video/mp4": ".mp4",
+        }
+        if ctype in mapping:
+            return mapping[ctype]
+    ext = mimetypes.guess_extension(hint.split("?")[0].lower()) or ".jpg"
+    return ".jpg" if ext == ".jpe" else ext
+
+
+def write_bytes(data: bytes, key_prefix: str = "", ext: str = ".jpg") -> str:
+    """写文件，返回 media key（相对 media 根的路径）。"""
+    key = f"{key_prefix + '/' if key_prefix else ''}{uuid.uuid4().hex}{ext}"
+    path = media_root() / key
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_bytes(data)
+    return key
+
+
+async def download_bytes(url: str, referer: str | None = None, timeout: float = 60.0) -> tuple[bytes, str]:
+    """下载远程字节。返回 (bytes, content_type)。"""
+    headers = {"Referer": referer} if referer else {}
+    headers.setdefault("User-Agent", "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7)")
+    async with httpx.AsyncClient(timeout=timeout, follow_redirects=True, verify=False) as client:
+        resp = await client.get(url, headers=headers)
+        resp.raise_for_status()
+        ctype = (resp.headers.get("content-type") or "application/octet-stream").split(";")[0].strip()
+        return resp.content, ctype
+
+
+async def save_from_url(url: str, key_prefix: str = "", referer: str | None = None) -> str:
+    data, ctype = await download_bytes(url, referer)
+    key = write_bytes(data, key_prefix, _ext_from_url_or_type(url, ctype))
+    return public_url(key)
+
+
+def local_path(stored_url_or_key: str) -> Path | None:
+    """stored_url（http.../media/xxx）或 key → 本地文件路径。"""
+    s = stored_url_or_key
+    if "/media/" in s:
+        s = s.split("/media/", 1)[1]
+    p = media_root() / s
+    return p if p.exists() else None