How to get host name in the workflow?

Hi,

   I've a requirement where I need to get CQ Inbox url (http://<hostname>:<port>/inbox) in my custom workflow process. I thought of configuring url to some node and retriving from there.. but It's not the good approach as host name will be different for differnt CQ environments. So what is the best way of getting inbox url?

Env: CQ 5.6

Thanks

Siva