Searching by field

(from github.com/qmaxquique)
Perhaps this is a silly question, but how do I search by field?

For instance, I want to narrow down my searches by host/site, I was trying to do this:
curl http://localhost:8081/json -d"q=about&facet.field=site&facet.query=\"www.example.com\""

But l get “Invalid facet field: site”

Thanks!

(from github.com/marevol)
Supported fields are here. (site is not in that as default)
To add site, modify fess_config.properties as below:

query.additional.facet.fields=site

(from github.com/qmaxquique)
Thank you!