Django snippets: Allow template tags in a Flatpage's content

from django import template
from django.utils.safestring import mark_safe

register = template.Library()

class RenderNode(template.Node):

    def __init__(self, content):
        self.content = content
    
    def render(self, context):
        try:
            self.content = template.resolve_variable(self.content, context)
            return template.Template(self.content).render(template.Context(context, autoescape=False))
        except template.TemplateSyntaxError, e:
            return mark_safe("<strong>Template error: There is an error one of this page's template tags: <code>%s</code></small>" % e.message)


@register.tag(name='render')
def render_django(parser, token):
    " Example: {% render flatpage.content %}"
    content = token.split_contents()[-1]
    return RenderNode(content)
render_django.is_safe = True

This tag, as shown, can cause problems (infinite recursion being one) if you don't use it correctly.

Our internal CMS has a pages app similar to Flatpages, and a "chunks" app similar to django-chunks. Because most of our other apps are template-tag driven (FAQs, job postings, news, events, etc) I wanted a way to be able to write django template code right into a page or chunk's body from within the django admin.

This tag will let you write django template code into, for example, a Flatpage's content and render it with the current context. So if you had a template tag called "get_latest_news" and wanted to add latest news to a flatpage, just enter this in the flatpage's content:

{% get_latest_news 5 as news %}
{% for article in news %}
    <li>{{ article.title }}</li>
{% endfor %}

This ability has proven extremely useful to us. Please note this is just a "summary" snippet to illustrate the concept. Use in a production environment should include more robust error checking.

Author:: kylefox
Posted:: July 8, 2008
Language:: Python
Tags:: flatpages template
Score:: 2 (after 2 ratings)

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jezdez (on October 1, 2008):

Please have a look at the django-dbtemplates project that enables you to save templates in the database in an official way and uses an own template loader.

anentropic (on November 22, 2009):

@jezdez dbtemplates doesn't seem to address what kylefox is doing here, which is to allow use of templatetags in flatpages. Which seems more useful than just storing templates in the db (why bother?)... if you have to go through making view stubs for your templates then you lose the shortcut benefit of flatpages.

nice handy snippet, something like this should be part of flatpages!

Tarken (on February 25, 2010):

I had to make one small modification to this so that it would work within a loop:

In render, rather than reassigning to "self.content", I just use a local "content" variable. Otherwise I get some nasty huge TemplateSyntaxError.

Now I can use, for example:

{% for article in articles %}
    {% render article.title %}
{% endfor %}

Otherwise works great; I'm using this extensively in my sites. Thank you!

Django snippets

Allow template tags in a Flatpage's content

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