Purge varnish cache for a single url using varnishadm

Varnish is being used in a Wordpress website.

I would like to purge Varnish for a single URL instead of a whole domain.

With this command I can restart Varnish for the whole domain:

varnishadm -T :6082 -S /etc/varnish/secret 'ban req.http.host ~ \"http://www.foo.com\" && req.url ~ \"^/\"'

However I would like to purge varnish only for a single url.

Ex: www.foo.com/url_to_be_purged

I've tried the previous command replacing it with the single URL:

varnishadm -T :6082 -S /etc/varnish/secret 'ban req.http.host ~ \"http://www.foo.com/url_to_be_purged\" && req.url ~ \"^/\"'

But it didn't work, the URL still was a HIT in Varnish.

Any ideas of how can I achieve this?

UPDATE

As suggested ghloogh's answer, I've tried the following command:

varnishadm -T :6082 -S /etc/varnish/secret ban "req.http.host == http://www.foo.com && req.url == http://www.foo.com/url_to_be_purged"

I've also tried this variation:

varnishadm -T :6082 -S /etc/varnish/secret ban "req.http.host == http://www.foo.com && req.url == /url_to_be_purged"

But I still get a HIT in the URL and the data is not updated

Solution 1:

You don't need to specify scheme for hostname and you may use strict match instead of regex:

varnishadm -T 127.0.0.1:6082 -S /etc/varnish/secret ban "req.http.host == example.com && req.url == /some/url/"

You can try the following:

sudo varnishadm -S /etc/varnish/secret  -T 127.0.0.1:6082 "ban req.url ~ \"http://example.com/testimage.png$\""

worked for me.