feat/enhance the multi-modal support (#8818)

api/core/file/helpers.py

@@ -0,0 +1,48 @@
+import base64
+import hashlib
+import hmac
+import os
+import time
+
+from configs import dify_config
+
+
+def get_signed_file_url(upload_file_id: str) -> str:
+    url = f"{dify_config.FILES_URL}/files/{upload_file_id}/file-preview"
+
+    timestamp = str(int(time.time()))
+    nonce = os.urandom(16).hex()
+    key = dify_config.SECRET_KEY.encode()
+    msg = f"file-preview|{upload_file_id}|{timestamp}|{nonce}"
+    sign = hmac.new(key, msg.encode(), hashlib.sha256).digest()
+    encoded_sign = base64.urlsafe_b64encode(sign).decode()
+
+    return f"{url}?timestamp={timestamp}&nonce={nonce}&sign={encoded_sign}"
+
+
+def verify_image_signature(*, upload_file_id: str, timestamp: str, nonce: str, sign: str) -> bool:
+    data_to_sign = f"image-preview|{upload_file_id}|{timestamp}|{nonce}"
+    secret_key = dify_config.SECRET_KEY.encode()
+    recalculated_sign = hmac.new(secret_key, data_to_sign.encode(), hashlib.sha256).digest()
+    recalculated_encoded_sign = base64.urlsafe_b64encode(recalculated_sign).decode()
+
+    # verify signature
+    if sign != recalculated_encoded_sign:
+        return False
+
+    current_time = int(time.time())
+    return current_time - int(timestamp) <= dify_config.FILES_ACCESS_TIMEOUT
+
+
+def verify_file_signature(*, upload_file_id: str, timestamp: str, nonce: str, sign: str) -> bool:
+    data_to_sign = f"file-preview|{upload_file_id}|{timestamp}|{nonce}"
+    secret_key = dify_config.SECRET_KEY.encode()
+    recalculated_sign = hmac.new(secret_key, data_to_sign.encode(), hashlib.sha256).digest()
+    recalculated_encoded_sign = base64.urlsafe_b64encode(recalculated_sign).decode()
+
+    # verify signature
+    if sign != recalculated_encoded_sign:
+        return False
+
+    current_time = int(time.time())
+    return current_time - int(timestamp) <= dify_config.FILES_ACCESS_TIMEOUT