[Storage] Fix content range check for empty files (Azure#26872)

Author: daviddavis

sdk/storage/azure-storage-blob/CHANGELOG.md

@@ -7,6 +7,7 @@
 ### Breaking Changes
 
 ### Bugs Fixed
+- Fixed possible invalid content range exception that gets raised when downloading empty blobs through Azurite.
 
 ### Other Changes
 - Removed `msrest` dependency.

sdk/storage/azure-storage-blob/azure/storage/blob/_download.py

@@ -431,7 +431,7 @@ def _initial_request(self):
                 # Parse the total file size and adjust the download size if ranges
                 # were specified
                 self._file_size = parse_length_from_content_range(response.properties.content_range)
-                if not self._file_size:
+                if self._file_size is None:
                     raise ValueError("Required Content-Range response header is missing or malformed.")
                 # Remove any extra encryption data size from blob size
                 self._file_size = adjust_blob_size_for_encryption(self._file_size, self._encryption_data)

sdk/storage/azure-storage-blob/azure/storage/blob/aio/_download_async.py

@@ -353,7 +353,7 @@ async def _initial_request(self):
             # Parse the total file size and adjust the download size if ranges
             # were specified
             self._file_size = parse_length_from_content_range(response.properties.content_range)
-            if not self._file_size:
+            if self._file_size is None:
                 raise ValueError("Required Content-Range response header is missing or malformed.")
             # Remove any extra encryption data size from blob size
             self._file_size = adjust_blob_size_for_encryption(self._file_size, self._encryption_data)

sdk/storage/azure-storage-file-share/azure/storage/fileshare/_download.py

@@ -311,7 +311,7 @@ def _initial_request(self):
             # Parse the total file size and adjust the download size if ranges
             # were specified
             self._file_size = parse_length_from_content_range(response.properties.content_range)
-            if not self._file_size:
+            if self._file_size is None:
                 raise ValueError("Required Content-Range response header is missing or malformed.")
 
             if self._end_range is not None:

sdk/storage/azure-storage-file-share/azure/storage/fileshare/aio/_download_async.py

@@ -264,7 +264,7 @@ async def _initial_request(self):
             # Parse the total file size and adjust the download size if ranges
             # were specified
             self._file_size = parse_length_from_content_range(response.properties.content_range)
-            if not self._file_size:
+            if self._file_size is None:
                 raise ValueError("Required Content-Range response header is missing or malformed.")
 
             if self._end_range is not None: