1 files changed, 33 insertions, 3 deletions

diff --git a/nikola/plugins/template_jinja.py b/nikola/plugins/template_jinja.py
index 0893cf7..f88b2c0 100644
--- a/nikola/plugins/template_jinja.py
+++ b/nikola/plugins/template_jinja.py
@@ -1,7 +1,34 @@
+# Copyright (c) 2012 Roberto Alsina y otros.
+
+# Permission is hereby granted, free of charge, to any
+# person obtaining a copy of this software and associated
+# documentation files (the "Software"), to deal in the
+# Software without restriction, including without limitation
+# the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the
+# Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+# 
+# The above copyright notice and this permission notice
+# shall be included in all copies or substantial portions of
+# the Software.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+# PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
+# OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
 """Jinja template handlers"""
 
 import os
-import jinja2
+try:
+    import jinja2
+except ImportError:
+    jinja2 = None
 
 from nikola.plugin_categories import TemplateSystem
 
@@ -12,8 +39,10 @@ class JinjaTemplates(TemplateSystem):
     name = "jinja"
     lookup = None
 
-    def set_directories(self, directories):
+    def set_directories(self, directories, cache_folder):
         """Createa  template lookup."""
+        if jinja2 is None:
+            raise Exception('To use this theme you need to install the "Jinja2" package.')
         self.lookup = jinja2.Environment(loader=jinja2.FileSystemLoader(
             directories,
             encoding='utf-8',
@@ -21,7 +50,8 @@ class JinjaTemplates(TemplateSystem):
 
     def render_template(self, template_name, output_name, context):
         """Render the template into output_name using context."""
-
+        if jinja2 is None:
+            raise Exception('To use this theme you need to install the "Jinja2" package.')
         template = self.lookup.get_template(template_name)
         output = template.render(**context)
         if output_name is not None: