Files
dify/api/extensions/storage/file_presign_storage.py
2026-01-20 18:45:13 +08:00

84 lines
3.0 KiB
Python

import base64
import hashlib
import hmac
import os
import time
import urllib.parse
from collections.abc import Generator
from configs import dify_config
from extensions.storage.base_storage import BaseStorage
class FilePresignStorage(BaseStorage):
SIGNATURE_PREFIX = "storage-download"
def __init__(self, storage: BaseStorage):
super().__init__()
self._storage = storage
def save(self, filename: str, data: bytes):
self._storage.save(filename, data)
def load_once(self, filename: str) -> bytes:
return self._storage.load_once(filename)
def load_stream(self, filename: str) -> Generator:
return self._storage.load_stream(filename)
def download(self, filename: str, target_filepath: str):
self._storage.download(filename, target_filepath)
def exists(self, filename: str) -> bool:
return self._storage.exists(filename)
def delete(self, filename: str):
self._storage.delete(filename)
def scan(self, path: str, files: bool = True, directories: bool = False) -> list[str]:
return self._storage.scan(path, files=files, directories=directories)
def get_download_url(self, filename: str, expires_in: int = 3600) -> str:
try:
return self._storage.get_download_url(filename, expires_in)
except NotImplementedError:
return self._generate_signed_proxy_url(filename)
def get_upload_url(self, filename: str, expires_in: int = 3600) -> str:
try:
return self._storage.get_upload_url(filename, expires_in)
except NotImplementedError:
return self._generate_signed_upload_url(filename)
def _generate_signed_upload_url(self, filename: str) -> str:
# TODO: Implement this
raise NotImplementedError("This storage backend doesn't support pre-signed URLs")
def _generate_signed_proxy_url(self, filename: str) -> str:
base_url = dify_config.FILES_URL
encoded_filename = urllib.parse.quote(filename, safe="")
url = f"{base_url}/files/storage/{encoded_filename}/download"
timestamp = str(int(time.time()))
nonce = os.urandom(16).hex()
sign = self._create_signature(filename, timestamp, nonce)
query = urllib.parse.urlencode({"timestamp": timestamp, "nonce": nonce, "sign": sign})
return f"{url}?{query}"
@classmethod
def _create_signature(cls, filename: str, timestamp: str, nonce: str) -> str:
key = dify_config.SECRET_KEY.encode()
msg = f"{cls.SIGNATURE_PREFIX}|{filename}|{timestamp}|{nonce}"
sign = hmac.new(key, msg.encode(), hashlib.sha256).digest()
return base64.urlsafe_b64encode(sign).decode()
@classmethod
def verify_signature(cls, *, filename: str, timestamp: str, nonce: str, sign: str) -> bool:
expected_sign = cls._create_signature(filename, timestamp, nonce)
if sign != expected_sign:
return False
current_time = int(time.time())
return current_time - int(timestamp) <= dify_config.FILES_ACCESS_TIMEOUT