1 files changed, 17 insertions, 9 deletions
diff --git a/nikola/plugins/template_jinja.py b/nikola/plugins/template_jinja.py
index f88b2c0..b6d762b 100644
--- a/nikola/plugins/template_jinja.py
+++ b/nikola/plugins/template_jinja.py
@@ -8,11 +8,11 @@
 # 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
@@ -25,10 +25,11 @@
 """Jinja template handlers"""
 
 import os
+import json
 try:
     import jinja2
 except ImportError:
-    jinja2 = None
+    jinja2 = None  # NOQA
 
 from nikola.plugin_categories import TemplateSystem
 
@@ -39,19 +40,26 @@ class JinjaTemplates(TemplateSystem):
     name = "jinja"
     lookup = None
 
+    def __init__(self):
+        """ initialize Jinja2 wrapper with extended set of filters"""
+        if jinja2 is None:
+            return
+        self.lookup = jinja2.Environment()
+        self.lookup.filters['tojson'] = json.dumps
+
     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',
-            ))
+            raise Exception('To use this theme you need to install the '
+                            '"Jinja2" package.')
+        self.lookup.loader = jinja2.FileSystemLoader(directories,
+                                                     encoding='utf-8')
 
     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.')
+            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: