Jinja nested rendering on variable content

Question

Say I have actual jinja template code in a variable X. Let us say the content of X is "{{ some_other_variable }}".

How can I display X while also rendering its content?

e.g., this does not work:

{{ X }}

As it simply renders this to screen "{{ some_other_variable }}" rather than the contents of some_other_variable.

The reason I'm doing it this way is that I have a site in which (trusted) users can create posts which themselves may contain jinja template code. The view page displays these posts, but due to the above problem, renders them directly, rather than substituting variables as I'd like.

Answer 1

I know it's a bit late :) but here's one solution without impacting template code:

import jinja2
def recursive_render(tpl, values):
     prev = tpl
     while True:
         curr = jinja2.Template(prev).render(**values)
         if curr != prev:
             prev = curr
         else:
             return curr

Test run:

>>> recursive_render("Hello {{X}}!", dict(X="{{name}}", name="world"))
u'Hello world!'

Note that this is not very efficient, since the template must be reparsed from scratch on every iteration.

Answer 2

Create new filter:

from jinja2 import contextfilter, Markup

@contextfilter
def subrender_filter(context, value):
    _template = context.eval_ctx.environment.from_string(value)
    result = _template.render(**context)
    if context.eval_ctx.autoescape:
        result = Markup(result)
    return result

env = Environment()
env.filters['subrender'] = subrender_filter

And then use it in template:

{{ "Hello, {{name}}"|subrender }}