feat: custom AzureStorage class

Inherit from original AzureStorage (from django-storages) and override
the url-method to strip away sas-token from the url.

Refs: KK-1509

Author: nicobav

utils/storage.py

@@ -0,0 +1,15 @@
+from urllib.parse import urlparse, urlunparse
+
+from storages.backends.azure_storage import AzureStorage
+
+
+class AzureStorageWithoutQuerystringAuth(AzureStorage):
+    """
+    Extends AzureStorage to strip the SAS token from URLs, matching the
+    behaviour of the S3 and GCS backends in django-storages with querystring_auth=False.
+    """
+
+    def url(self, name, expire=None, parameters=None, mode="r"):
+        sas_url = super().url(name, expire=expire, parameters=parameters, mode=mode)
+        parsed_url = urlparse(sas_url)
+        return urlunparse(parsed_url._replace(query=""))

utils/tests/__init__.py

@@ -0,0 +1,60 @@
+from unittest.mock import patch
+
+import pytest
+from django.conf import settings
+from django.test import override_settings
+from django.utils.module_loading import import_string
+from storages.backends.azure_storage import AzureStorage
+
+from utils.storage import AzureStorageWithoutQuerystringAuth
+
+SAS_URL = (
+    "https://myaccount.blob.core.windows.net/mycontainer/myfile.jpg"
+    "?sv=2021-06-08&se=2026-01-01T00%3A00%3A00Z&sr=b&sp=r&sig=FAKESIG"
+)
+CLEAN_URL = "https://myaccount.blob.core.windows.net/mycontainer/myfile.jpg"
+
+
+def _make_storage(model=AzureStorageWithoutQuerystringAuth, **overrides):
+    """Return an AzureStorageWithoutQuerystringAuth with minimal required settings."""
+    kwargs = dict(
+        account_name="myaccount",
+        account_key="123454567",
+        azure_container="mycontainer",
+        expiration_secs=3600,
+    )
+    kwargs.update(overrides)
+    return model(**kwargs)
+
+
+@pytest.mark.parametrize(
+    "model, expected_url",
+    [
+        (AzureStorage, SAS_URL),
+        (AzureStorageWithoutQuerystringAuth, CLEAN_URL),
+    ],
+)
+@patch.object(AzureStorage, "url", return_value=SAS_URL)
+def test_url_querystring_auth(mock_url, model, expected_url):
+    storage = _make_storage(model=model)
+    result = storage.url("myfile.jpg")
+
+    assert result == expected_url
+
+
+@patch.object(AzureStorage, "url", return_value=SAS_URL)
+def test_url_querystring_auth_false_no_query_string_in_parent_url(mock_url):
+    storage = _make_storage()
+    result = storage.url("myfile.jpg")
+
+    assert result == CLEAN_URL
+    assert "?" not in result
+
+
+@override_settings(
+    STORAGES_DEFAULT_BACKEND="utils.storage.AzureStorageWithoutQuerystringAuth"
+)
+def test_default_storage_uses_azure_without_querystring_auth():
+    backend_class = import_string(settings.STORAGES_DEFAULT_BACKEND)
+    assert issubclass(backend_class, AzureStorage)
+    assert backend_class is AzureStorageWithoutQuerystringAuth