Fixes #1395: extends pelican.utils.strftime with `-` prefix to strip leading zeros

Adds the ability to use `-` prefix with C89 format codes to strip any
leading zeros.

3 files changed, 33 insertions, 5 deletions

diff --git a/docs/settings.rst b/docs/settings.rst
index df2fa722..71d23ab2 100644
--- a/docs/settings.rst
+++ b/docs/settings.rst
@@ -342,8 +342,12 @@ Date format and locale
 If no ``DATE_FORMATS`` are set, Pelican will fall back to
 ``DEFAULT_DATE_FORMAT``. If you need to maintain multiple languages with
 different date formats, you can set the ``DATE_FORMATS`` dictionary using the
-language name (``lang`` metadata in your post content) as the key. Regarding
-available format codes, see `strftime document of python`_ :
+language name (``lang`` metadata in your post content) as the key. 
+
+In addition to the standard C89 strftime format codes that are listed in
+`Python strftime documentation`_, you can use ``-`` character between ``%`` and
+the format character to remove any leading zeros. For example, ``%d/%m/%Y`` will
+output ``01/01/2014`` whereas ``%-d/%-m/%Y`` will result in ``1/1/2014``.
 
 .. parsed-literal::
 
@@ -382,7 +386,7 @@ can get a list of available locales via the ``locale -a`` command; see manpage
 `locale(1)`_ for more information.
 
 
-.. _strftime document of python: http://docs.python.org/library/datetime.html#strftime-strptime-behavior
+.. _Python strftime documentation: http://docs.python.org/library/datetime.html#strftime-strptime-behavior
 
 .. _locales on Windows: http://msdn.microsoft.com/en-us/library/cdax410z%28VS.71%29.aspx
 
diff --git a/pelican/tests/test_utils.py b/pelican/tests/test_utils.py
index df1918b5..7e770e65 100644
--- a/pelican/tests/test_utils.py
+++ b/pelican/tests/test_utils.py
@@ -280,6 +280,13 @@ class TestUtils(LoggedTestCase):
         self.assertEqual(utils.strftime(d, '%d/%m/%Y Øl trinken beim Besäufnis'),
                          '29/08/2012 Øl trinken beim Besäufnis')
 
+        # alternative formatting options
+        self.assertEqual(utils.strftime(d, '%-d/%-m/%y'), '29/8/12')
+        self.assertEqual(utils.strftime(d, '%-H:%-M:%-S'), '0:0:0')
+
+        d = utils.SafeDatetime(2012, 8, 9)
+        self.assertEqual(utils.strftime(d, '%-d/%-m/%y'), '9/8/12')
+
 
     # test the output of utils.strftime in a different locale
     # Turkish locale
diff --git a/pelican/utils.py b/pelican/utils.py
index 5e4822ba..96a0ab93 100644
--- a/pelican/utils.py
+++ b/pelican/utils.py
@@ -42,8 +42,11 @@ def strftime(date, date_format):
     replacing formatted output back.
     '''
 
+    c89_directives = 'aAbBcdfHIjmMpSUwWxXyYzZ%'
+    strip_zeros = lambda x: x.lstrip('0') or '0'
+
     # grab candidate format options
-    format_options = '%.'
+    format_options = '%[-]?.'
     candidates = re.findall(format_options, date_format)
 
     # replace candidates with placeholders for later % formatting
@@ -56,14 +59,28 @@ def strftime(date, date_format):
     formatted_candidates = []
     for candidate in candidates:
         # test for valid C89 directives only
-        if candidate[1] in 'aAbBcdfHIjmMpSUwWxXyYzZ%':
+        if candidate[-1] in c89_directives:
+            # check for '-' prefix
+            if len(candidate) == 3:
+                # '-' prefix
+                candidate = '%{}'.format(candidate[-1])
+                conversion = strip_zeros
+            else:
+                conversion = None
+
+            # format date
             if isinstance(date, SafeDatetime):
                 formatted = date.strftime(candidate, safe=False)
             else:
                 formatted = date.strftime(candidate)
+
             # convert Py2 result to unicode
             if not six.PY3 and enc is not None:
                 formatted = formatted.decode(enc)
+
+            # strip zeros if '-' prefix is used
+            if conversion:
+                formatted = conversion(formatted)
         else:
             formatted = candidate
         formatted_candidates.append(formatted)