Using the generated CSP nonce

When CSP_INCLUDE_NONCE_IN is configured, the nonce value is returned in the CSP header. To actually make the browser do anything with this value, you will need to include it in the attributes of the tags that you wish to mark as safe.

Middleware

Installing the middleware creates a lazily evaluated property csp_nonce and attaches it to all incoming requests.

    MIDDLEWARE_CLASSES = (
    #...
    'csp.middleware.CSPMiddleware',
    #...
)

This value can be accessed directly on the request object in any view or template and manually appended to any script element like so -

<script nonce="{{request.csp_nonce}}">
        var hello="world";
</script>

Assuming the CSP_INCLUDE_NONCE_IN list contains the script-src directive, this will result in the above script being allowed.

Context Processor

This library contains an optional context processor, adding csp.context_processors.nonce to your configured context processors exposes a variable called nonce into the global template context. This is simple shorthand for request.csp_nonce, but can be useful if you have many occurrences of script tags.

<script nonce="{{nonce}}">
    var hello="world";
</script>

Django Template Tag/Jinja Extension

Note

If you’re making use of csp.extensions.NoncedScript you need to have jinja2>=2.9.6 installed, so please make sure to either use django-csp[jinja2] in your requirements or define it yourself.

Since it can be easy to forget to include the nonce property in a script tag, there is also a script template tag available for both Django templates and Jinja environments.

This tag will output a properly nonced script every time. For the sake of syntax highlighting, you can wrap the content inside of the script tag in <script> html tags, which will be subsequently removed in the rendered output. Any valid script tag attributes can be specified and will be forwarded into the rendered html.

Django:

{% load csp %}
{% script type="application/javascript" async=False %}
        <script>
                var hello='world';
        </script>
{% endscript %}

Jinja:

(assumes csp.extensions.NoncedScript is added to the jinja extensions setting)

{% script type="application/javascript" async=False %}
        <script>
                var hello='world';
        </script>
{% endscript %}

Will output -

<script nonce='123456' type="application/javascript" async=false></script>