use zipinfo to fix permission

Author: Raphael Dussin

docs/release.rst

@@ -4,6 +4,10 @@ Release notes
 Upcoming Release
 ----------------
 
+* Add intermediate step (using ``zipfile.ZipInfo`` object) to write
+  inside ``ZipStore`` to solve too restrictive permission issue.
+  By :user:`Raphael Dussin <raphaeldussin`; :issue:`505`.
+
 * Add key normalization option for ``DirectoryStore``, ``NestedDirectoryStore``,
   ``TempStore``, and ``N5Store``.
   By :user:`James Bourbeau <jrbourbeau>`; :issue:`459`.
@@ -21,7 +25,7 @@ Upcoming Release
 * Upgrade dependencies in the test matrices and resolve a
   compatibility issue with testing against the Azure Storage
   Emulator. By :user:`alimanfoo`; :issue:`468`, :issue:`467`.
-  
+
 * Do not rename Blosc parameters in n5 backend and add `blocksize` parameter,
   compatible with n5-blosc. By :user:`axtimwalde`, :issue:`485`.
 
@@ -94,7 +98,7 @@ Enhancements
 ~~~~~~~~~~~~
 
 * New storage backend, backed by Azure Blob Storage, class :class:`zarr.storage.ABSStore`.
-  All data is stored as block blobs. By :user:`Shikhar Goenka <shikarsg>`, 
+  All data is stored as block blobs. By :user:`Shikhar Goenka <shikarsg>`,
   :user:`Tim Crone <tjcrone>` and :user:`Zain Patel <mzjp2>`; :issue:`345`.
 
 * Add "consolidated" metadata as an experimental feature: use

zarr/storage.py

@@ -33,6 +33,7 @@
 from pickle import PicklingError
 from threading import Lock, RLock
 import uuid
+import time
 
 from numcodecs.compat import ensure_bytes, ensure_contiguous_ndarray
 from numcodecs.registry import codec_registry
@@ -1254,7 +1255,22 @@ def __setitem__(self, key, value):
             err_read_only()
         value = ensure_contiguous_ndarray(value)
         with self.mutex:
-            self.zf.writestr(key, value)
+            # writestr(key, value) writes with default permissions from
+            # zipfile (600) that are too restrictive, build ZipInfo for
+            # the key to work around limitation
+            keyinfo = zipfile.ZipInfo(filename=key,
+                                      date_time=time.localtime(time.time())[:6])
+            keyinfo.compress_type = self.compression
+            if keyinfo.filename[-1] == os.sep:
+                keyinfo.external_attr = 0o40775 << 16   # drwxrwxr-x
+                keyinfo.external_attr |= 0x10           # MS-DOS directory flag
+            else:
+                keyinfo.external_attr = 0o644 << 16     # ?rw-r--r--
+
+            if isinstance(value, str):
+                value = value.encode("utf-8")
+
+            self.zf.writestr(keyinfo, value)
 
     def __delitem__(self, key):
         raise NotImplementedError