added cache and FileResponse for range requests to seek meia

app/api.py

@@ -18,6 +18,7 @@ api_key_header = APIKeyHeader(name="X-API-Key")
 FTP_URL = os.getenv("FTP_URL")
 FTP_LOGIN = os.getenv("FTP_LOGIN")
 FTP_PASSWORD = os.getenv("FTP_PASSWORD")
+CACHE_DIR = "cache"
 
 def verify_api_key(api_key: str = Security(api_key_header)):
     if api_key != API_KEY:
@@ -58,29 +59,38 @@ async def save_file(file: UploadFile = File(...), api_key: str = Depends(verify_
 
             ftp.storbinary(f"STOR {FILES_DIR}/{file_url}", buffer)
             ftp.quit()
+
+            cached = os.path.join(CACHE_DIR, file_url)
+            if os.path.exists(cached):
+                os.remove(cached)
+
             return {"status": "saved", "filename": file_url}
         except Exception as e:
             db.remove_file(file_url)
+
             return {"status": "error", "message": f"Could not save file {file_url}: {e}"}
     else:
         return {"status": "file_exists", "filename": existed_url}
 
 @app.get("/file/{filename}")
 async def get_file(filename: str, raw: bool = False, api_key: str = Depends(verify_api_key)):
-    try:
-        ftp = FTP(FTP_URL)
-        ftp.login(FTP_LOGIN, FTP_PASSWORD)
-        buffer = BytesIO()
-        ftp.retrbinary(f"RETR {FILES_DIR}/{filename}", buffer.write)
-        ftp.quit()
-        buffer.seek(0)
-    except Exception as e:
-        raise HTTPException(status_code=404, detail=f"File not found: {e}")
+    local_path = os.path.join(CACHE_DIR, filename)
+
+    if not os.path.exists(local_path):
+        try:
+            ftp = FTP(FTP_URL)
+            ftp.login(FTP_LOGIN, FTP_PASSWORD)
+            with open(local_path, "wb") as f:
+                ftp.retrbinary(f"RETR {FILES_DIR}/{filename}", f.write)
+            ftp.quit()
+        except Exception as e:
+            raise HTTPException(status_code=404, detail=f"File not found: {e}")
 
     if raw:
-        return PlainTextResponse(buffer.getvalue().decode("utf-8", errors="ignore"))
+        with open(local_path, "r", encoding="utf-8", errors="ignore") as f:
+            return PlainTextResponse(f.read())
 
-    return StreamingResponse(buffer, media_type="application/octet-stream", headers={"Content-Disposition": f'attachment; filename="{filename}"'})
+    return FileResponse(local_path, filename=filename)
 
 
 from ftplib import FTP