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Safely JSON-encode objects in your Django template
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| from django.core.serializers.json import DjangoJSONEncoder | |
| from django.template import Library | |
| from json import dumps as json_dumps | |
| register = Library() | |
| @register.filter | |
| def json(data): | |
| """ | |
| Safely JSON-encode an object. | |
| To protect against XSS attacks, HTML special characters (<, >, &) and unicode newlines | |
| are replaced by escaped unicode characters. Django does not escape these characters | |
| by default. | |
| Output of this method is not marked as HTML safe. If you use it inside an HTML | |
| attribute, it must be escaped like regular data: | |
| <div data-user="{{ data|json }}"> | |
| If you use it inside a <script> tag, then the output does not need to be escaped, | |
| so you can mark it as safe: | |
| <script> | |
| var user = {{ data|json|safe }}; | |
| </script> | |
| Escaped characters taken from Rails json_escape() helper: | |
| https://github.com/rails/rails/blob/v4.2.5/activesupport/lib/active_support/core_ext/string/output_safety.rb#L60-L113 | |
| """ | |
| unsafe_chars = { | |
| '&': '\\u0026', | |
| '<': '\\u003c', | |
| '>': '\\u003e', | |
| '\u2028': '\\u2028', | |
| '\u2029': '\\u2029'} | |
| json_str = json_dumps(data, cls=DjangoJSONEncoder) | |
| for (c, d) in unsafe_chars.items(): | |
| json_str = json_str.replace(c, d) | |
| return json_str |
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