Ticket #17419: json-filter.diff

django/template/defaultfilters.py

@@ -9 +9 @@
 
 from django.template.base import Variable, Library
 from django.conf import settings
-from django.utils import formats
+from django.utils import formats, simplejson
 from django.utils.dateformat import format, time_format
 from django.utils.encoding import force_unicode, iri_to_uri
 from django.utils.html import (conditional_escape, escapejs, fix_ampersands,
@@ -832 +832 @@
         return ugettext("%s TB") % filesize_number_format(bytes / (1024 * 1024 * 1024 * 1024))
     return ugettext("%s PB") % filesize_number_format(bytes / (1024 * 1024 * 1024 * 1024 * 1024))
 
+@register.filter(is_safe=True)
+def json(value):
+    """
+    Returns the json representation of value.
+
+    This filter is most often used within <script> tags. Per the HTML
+    spec (though not XHTML) all text within <script> tags is CDATA and
+    therefore does not need escaping. Thus, the output is marked safe,
+    even though no escaping is done.
+
+    When using this filter outside <script> tags, you must explicitly
+    force_escape the output: {{ data|json|force_escape }}.
+    """
+    return mark_safe(simplejson.dumps(value))
+
 @register.filter(is_safe=False)
 def pluralize(value, arg=u's'):
     """

docs/ref/templates/builtins.txt

@@ -1665 +1665 @@
 If ``value`` is the list ``['a', 'b', 'c']``, the output will be the string
 ``"a // b // c"``.
 
+.. templatefilter:: json
+
+json
+^^^^
+
+.. versionadded:: 1.4
+
+Coverts a python datastructure of possibly nested dictionaries and lists into
+a json string.
+
+For example::
+
+    <script>
+        var json_data = {{ value|json }};
+    </script>
+
+If ``value`` is the python dictionary with nested list
+``{'hello': ['world', 'wide']}``, the output will be the string
+``'{"hello": ["world", "wide"]}'``.
+
+This filter is most often used within ``<script>`` tags. Per the
+HTML spec (though not XHTML) all text within ``<script>`` tags is
+CDATA and therefore does not need escaping. Thus, the output of this filter
+is marked safe, even though no escaping is done.
+
+When using this filter outside ``<script>`` tags, you must explicitly
+force_escape the output. For example::
+
+    {{ value|json|force_escape }}
+
 .. templatefilter:: last
 
 last

tests/regressiontests/templates/filters.py

@@ -106 +106 @@
         'filter-lower01': ("{% autoescape off %}{{ a|lower }} {{ b|lower }}{% endautoescape %}", {"a": "Apple & banana", "b": mark_safe("Apple & banana")}, u"apple & banana apple & banana"),
         'filter-lower02': ("{{ a|lower }} {{ b|lower }}", {"a": "Apple & banana", "b": mark_safe("Apple & banana")}, u"apple & banana apple & banana"),
 
+        # json filter #17419
+        'filter-json01': ("{{ data|json }}", {"data": {"hello": ["world", "universe"]}}, u'{"hello": ["world", "universe"]}'),
+        'filter-json02': ("{{ data|json }}", {"data": {"foo": "<bar>"}}, u'{"foo": "<bar>"}'),
+        'filter-json03': ("{{ data|json }}", {"data": {"foo": 'ba"r'}}, u'{"foo": "ba\\"r"}'),
+
         # The make_list filter can destroy existing escaping, so the results are
         # escaped.
         'filter-make_list01': ("{% autoescape off %}{{ a|make_list }}{% endautoescape %}", {"a": mark_safe("&")}, u"[u'&']"),