add storage factory (#3922)

api/extensions/storage/base_storage.py

@@ -0,0 +1,38 @@
+"""Abstract interface for file storage implementations."""
+from abc import ABC, abstractmethod
+from collections.abc import Generator
+
+from flask import Flask
+
+
+class BaseStorage(ABC):
+    """Interface for file storage.
+    """
+    app = None
+
+    def __init__(self, app: Flask):
+        self.app = app
+
+    @abstractmethod
+    def save(self, filename, data):
+        raise NotImplementedError
+
+    @abstractmethod
+    def load_once(self, filename: str) -> bytes:
+        raise NotImplementedError
+
+    @abstractmethod
+    def load_stream(self, filename: str) -> Generator:
+        raise NotImplementedError
+
+    @abstractmethod
+    def download(self, filename, target_filepath):
+        raise NotImplementedError
+
+    @abstractmethod
+    def exists(self, filename):
+        raise NotImplementedError
+
+    @abstractmethod
+    def delete(self, filename):
+        raise NotImplementedError