How to get a list of current variables from Jinja 2 template?

Question

If I return a Jinja2 template like so: return render_response('home.htm', **context)

How do then get a list of the variables in context from within the template?

Answer 1

Technically, because context is not passed as a named dictionary, a little work is required to generate a list of the context variables from inside a template. It is possible though.

1. Define a Jinja context function to return the jinja2.Context object, which is essentially a dictionary of the global variables/functions

2. Make that function available in the global namespace; i.e. a jinja2.Environment or jinja2.Template globals dictionary

3. Optionally, filter objects from the context; for instance, use callable() to skip Jinja's default global helper functions (range, joiner, etc.). This may be done in the context function or the template; wherever it makes the most sense.

Example:

>>> import jinja2 >>>  >>> @jinja2.contextfunction ... def get_context(c): ...         return c ...  >>> tmpl = """  ... {% for key, value in context().items() %} ...     {% if not callable(value) %} ...         {{ key }}:{{ value }} ...     {% endif %} ... {% endfor %} ... """ >>>  >>> template = jinja2.Template(tmpl) >>> template.globals['context'] = get_context >>> template.globals['callable'] = callable >>> >>> context = {'a': 1, 'b': 2, 'c': 3} >>>  >>> print(template.render(**context))         a:1         c:3         b:2 

[Alternately, call render_response with ('home.htm', context=context) to make the other solution work.]