Add calendar-description, addressbook-description to the meta data

When a CalDAV collection has calendar-description set and vdirsyncer
synchronizes the “meta” data, synchronize also the calendar description.

-- likewise for addressbook-description and calendar-order

Author: dilyanpalauzov

CHANGELOG.rst

@@ -9,6 +9,10 @@ Package maintainers and users who have to manually update their installation
 may want to subscribe to `GitHub's tag feed
 <https://github.com/pimutils/vdirsyncer/tags.atom>`_.
 
+- Add "description" and "order" as metadata.  These fetch the CalDAV:
+  calendar-description, CardDAV:addressbook-description and apple-ns:calendar-order
+  properties.
+
 Version 0.16.8
 ==============
 

docs/config.rst

@@ -116,9 +116,12 @@ Pair Section
 - ``metadata``: Metadata keys that should be synchronized when ``vdirsyncer
   metasync`` is executed. Example::
 
-      metadata = ["color", "displayname"]
+      metadata = ["color", "displayname", "description", "order"]
 
-  This synchronizes the ``color`` and the ``displayname`` properties. The
+  This synchronizes the ``http://apple.com/ns/ical/:calendar-color``,
+  ``DAV:displayname``, ``CalDAV:calendar-description``,
+  ``CardDAV:addressbook-description`` and
+  ``http://apple.com/ns/ical/:calendar-order`` properties. The
   ``conflict_resolution`` parameter applies here as well.
 
 .. _storage_config:

docs/vdir.rst

@@ -56,8 +56,11 @@ have any file extensions.
   known from CSS, for example) are allowed. The prefixing ``#`` must be
   present.
 
-- A file called ``displayname`` contains a UTF-8 encoded label that may be used
-  to represent the vdir in UIs.
+- A file called ``order`` inside the vdir includes the relative order
+  of the calendar, a property that is only relevant in UI design.
+
+- Files called ``displayname`` and ``description`` contain a UTF-8 encoded label/
+  description, that may be used to represent the vdir in UIs.
 
 Writing to vdirs
 ================

vdirsyncer/storage/dav.py

@@ -728,6 +728,8 @@ class CalDAVStorage(DAVStorage):
     _property_table = dict(DAVStorage._property_table)
     _property_table.update({
         'color': ('calendar-color', 'http://apple.com/ns/ical/'),
+        'description': ('calendar-description', 'urn:ietf:params:xml:ns:caldav'),
+        'order': ('calendar-order', 'http://apple.com/ns/ical/'),
     })
 
     def __init__(self, start_date=None, end_date=None,
@@ -843,3 +845,8 @@ class CardDAVStorage(DAVStorage):
             </C:addressbook-multiget>'''
 
     get_multi_data_query = '{urn:ietf:params:xml:ns:carddav}address-data'
+
+    _property_table = dict(DAVStorage._property_table)
+    _property_table.update({
+        'description': ('addressbook-description', 'urn:ietf:params:xml:ns:carddav'),
+    })