redirecting with url_for to a path with query params in flask

Question

So let's say I have a template with a couple of links, the links will be like this:

<a class='btn btn-primary' href='/?chart=new_chart&chart=other_chart'>View Summary</a> 

However, most of the times when I have done links or included resources, I have used the following syntax:

<script src="{{ url_for('static', filename='some_silly_js') }}"></script> 

is it possible to do a url_for with query parameters? Something like:

<a href="{{ url_for('stats', query_params={chart: [new_chart, other_chart]}) }}>View More</a> 

Answer 1

Any extra keyword parameters passed to url_for() which are not supported by the route are automatically added as query parameters.

For repeated values, pass in a list:

<a href="{{ url_for('stats', chart=[new_chart, other_chart]) }}>View More</a> 

Flask will then:

1. find the stats endpoint
2. fill in any required route parameters
3. transform any remaining keyword parameters to a query string

Demo, with 'stats' being the endpoint name for /:

>>> url_for('stats', chart=['foo', 'bar']) '/?chart=foo&chart=bar'