python - Reference template variable within Jinja expression

Question

I have a route defined like this:

@app.route('/magic/<filename>')
def moremagic(filename):
    pass

And now in a template I want to call that route using url_for() like so:

<h1>you uploaded {{ name }}<h1>
<a href="{{ url_for('/magic/<filename>') }}">Click to see magic happen</a>

I have tried:

<a href="{{ url_for('/magic', filename={{ name }}) }}">Click to see magic happen</a>

That throws a jinja2.TemplateSyntaxError: expected token ':' got }

Can anyone suggest how to get the {{ name }} that appears in the template into the url_for() so that when I click I call the correct app.route?

Answer 1

Everything inside the {{ ... }} is a Python-like expression. You don't need to use another {{ ... }} inside that to reference variables.

Drop the extra brackets:

<h1>you uploaded {{ name }}<h1>
<a href="{{ url_for('moremagic', filename=name) }}">Click to see magic happen</a>

(Note that the url_for() function takes the endpoint name, not a URL path; the name defaults to the name of the function, moremagic in your example).