CODEWITHSUNDEEP
pythonjinja2
chrisst
chrisst

Reputation: 1766

How to call a python function with no parameters in a jinja2 template

I have managed to call python functions from jinja2 by using custom filters, but I can only seem to call functions with one or more parameters. In the following I have had to pass a junk parameter in order to treat ctest as a function rather than a variable.

It also doesn't work if I just call {{ ctest() }}.

Is there a different way to force this to be a function call or should I be using a different approach?

code:

def ctest(stuff):
    return "yeah!"

template_env = jinja2.Environment (loader = jinja2.FileSystemLoader(template_file_root))
#custom filters
template_env.filters['ctest'] = ctest

template:

Working? {{ junk|ctest }}

output:

working? yeah!

Upvotes: 5

Views: 6108

Answers (3)

Roland Puntaier
Roland Puntaier

Reputation: 3521

{{func()}} renders the output. {% call func() %}{%endcall%} calls func() with a caller parameter.

In jinja there really seems to be no straightforward way to call a python function in the template without rendering it or other template side effects. The workaround I came up with is:

{% if func() %}{% endif %}

Upvotes: 0

chrisst
chrisst

Reputation: 1766

Summarizing the comments into an answer:

The ability to call functions by adding it to filters isn't really the correct way of going about this since (as Wooble pointed out) I'm not looking to filter anything.

Instead the function just needs to be added to the template_env.globals:

template_globals.filters['ctest'] = ctest

Upvotes: 1

Wooble
Wooble

Reputation: 90007

Well, they're filters, so they expect to be filtering something. If the motivation is that you want to function to be callable from outside a template without passing any arguments, change the signature to:

def ctest(*args):

and then just ignore the arguments; it will work if it's passed no arguments or any number of them.

Upvotes: 1

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