views: meta_highwire rendering fix for old dates

* Fixes issue which occurs when rendering publication dates older than
  1900-01-01. (closes #47)

examples/templates/index.html

@@ -1,3 +1,2 @@
-{% set mydate = mydate|from_isodate -%}
-Today is {{ mydate.strftime('%Y-%m-%d') }}
+Today is {{ mydate|to_arrow|format_arrow('YYYY-MM-DD') }}
 <img src="{{ url_for('invenio_formatter_badges.badge', title='DOI', value='invenio.12345', ext='svg') }}"></img>

invenio_formatter/__init__.py

@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 #
 # This file is part of Invenio.
-# Copyright (C) 2015 CERN.
+# Copyright (C) 2015, 2016, 2017 CERN.
 #
 # Invenio is free software; you can redistribute it
 # and/or modify it under the terms of the GNU General Public License as
@@ -36,8 +36,7 @@
 
 .. code-block:: html
 
-    {% set mydate = mydate|from_isodate -%}
-    Today is {{ mydate.strftime('%Y-%m-%d') }}
+    Today is {{ mydate|to_arrow|format_arrow('YYYY-MM-DD') }}
 
     Your book: {{ badge_svg('isbn','9780399547331')|safe }}
 

invenio_formatter/ext.py

@@ -29,7 +29,8 @@
 from pkg_resources import DistributionNotFound, get_distribution
 
 from . import config
-from .filters.datetime import from_isodate, from_isodatetime
+from .filters.datetime import format_arrow, from_isodate, from_isodatetime, \
+    to_arrow
 from .views import create_badge_blueprint
 
 
@@ -55,6 +56,8 @@ def init_app(self, app):
         app.jinja_env.filters.update(
             from_isodate=from_isodate,
             from_isodatetime=from_isodatetime,
+            to_arrow=to_arrow,
+            format_arrow=format_arrow,
         )
 
         if app.config['FORMATTER_BADGES_ENABLE']:

invenio_formatter/filters/datetime.py

@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 #
 # This file is part of Invenio.
-# Copyright (C) 2015, 2016 CERN.
+# Copyright (C) 2015, 2016, 2017 CERN.
 #
 # Invenio is free software; you can redistribute it
 # and/or modify it under the terms of the GNU General Public License as
@@ -53,3 +53,25 @@ def from_isodatetime(value, strict=False):
     """
     if value or strict:
         return arrow.get(value).datetime
+
+
+def format_arrow(value, format_string):
+    """Format an arrow datetime object.
+
+    :param value: The arrow datetime object.
+    :param format_string: The date format string
+    :returns: Returns a string representation of the given arrow datetime
+        object, formatted according to the given format string.
+
+    .. note::
+        Do not use this filter to format date/times presented to an end
+        user. Instead use ``datetimeformat`` or ``dateformat`` from
+        Invenio-I18N.
+    """
+    assert isinstance(value, arrow.Arrow)
+    return value.format(format_string)
+
+
+def to_arrow(value):
+    """Convert a Date object to an arrow datetime object."""
+    return arrow.get(value)

invenio_formatter/templates/invenio_formatter/macros/meta.html

@@ -1,6 +1,6 @@
 {#
 # This file is part of Invenio.
-# Copyright (C) 2015, 2016 CERN.
+# Copyright (C) 2015, 2016, 2017 CERN.
 #
 # Invenio is free software; you can redistribute it
 # and/or modify it under the terms of the GNU General Public License as
@@ -58,7 +58,7 @@
     <meta name="citation_publisher" content="{{publisher}}" />
     {%- endif %}
     {%- if publication_date %}
-    <meta name="citation_publication_date" content="{{publication_date.strftime('%Y/%m/%d')}}" />
+    <meta name="citation_publication_date" content="{{publication_date|to_arrow|format_arrow('YYYY/MM/DD')}}" />
     {%- endif %}
     {%- if doi %}
     <meta name="citation_doi" content="{{doi}}" />