1 files changed, 59 insertions, 0 deletions

diff --git a/mailman/utilities/string.py b/mailman/utilities/string.py
new file mode 100644
index 000000000..2ca8c2021
--- /dev/null
+++ b/mailman/utilities/string.py
@@ -0,0 +1,59 @@
+# Copyright (C) 2009 by the Free Software Foundation, Inc.
+#
+# This file is part of GNU Mailman.
+#
+# GNU Mailman is free software: you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your option)
+# any later version.
+#
+# GNU Mailman is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+# more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# GNU Mailman.  If not, see <http://www.gnu.org/licenses/>.
+
+"""String utilities."""
+
+from __future__ import absolute_import, unicode_literals
+
+__metaclass__ = type
+__all__ = [
+    'expand'
+    ]
+
+
+import logging
+from string import Template
+
+log = logging.getLogger('mailman.error')
+
+
+
+def expand(template, substitutions, template_class=Template):
+    """Expand string template with substitutions.
+
+    :param template: A PEP 292 $-string template.
+    :type template: string
+    :param substitutions: The substitutions dictionary.
+    :type substitutions: dict
+    :param template_class: The template class to use.
+    :type template_class: class
+    :return: The substituted string.
+    :rtype: string
+    """
+    # Python 2.6 requires ** dictionaries to have str, not unicode keys, so
+    # convert as necessary.  Note that string.Template uses **.  For our
+    # purposes, keys should always be ascii.  Values though can be anything.
+    cooked = substitutions.__class__()
+    for key in substitutions:
+        if isinstance(key, unicode):
+            key = key.encode('ascii')
+        cooked[key] = substitutions[key]
+    try:
+        return template_class(template).safe_substitute(cooked)
+    except (TypeError, ValueError):
+        # The template is really screwed up.
+        log.exception('broken template: %s', template)