If you are not familiar with Jinja, check out Getting Started with Jinja.

Let's say you have a URL like this.

http://www.example.com/foo?bar=hello

request can be used to return the URL. This is based on.

• GET HTTP Headers using the request module
• Get keys and values from URL

For example.

endpoint = {{ url_for(request.endpoint) }}
<br />
url_rule.endpoint = {{ url_for(request.url_rule.endpoint) }}
<br />
view_args = {{ url_for(request.endpoint, **request.view_args) }}
<br />
bar = {{ request.args.get('bar') }}  

Which should return.

endpoint = /
url_rule.endpoint = /foo
view_args = /foo
bar = hello