how to publish wordpress subsite from root / - URI Masking

Have to ask, can't you just move the wordpress application to the root instead? There are multiple articles out there on how to do this.

Here's one:

https://wordpress.org/support/topic/moving-wordpress-from-subfolder-to-root-folder

That said, you CAN rewrite the incoming requests to append "/wordpress" with an iRule:

when HTTP_REQUEST {

    set uri [string tolower [HTTP::uri]]
    set host [string tolower [HTTP::host]]

    Make sure that the site accessed is myapp.mhsite.com 
    if { $host -eq "myapp.mhsite.com" } {

        Add a the wordpress folder to the request for the backend calls if the wordpress path is not there already
        if { ! $uri starts_with "/wordpress" } { 
            HTTP::uri "/wordpress$uri"
        }
    }

}

But this would not handle the outgoing response containing links to /wordpress. For that you'd need to enable a stream profile which replaces /wordpress with "":

https://support.f5.com/kb/en-us/solutions/public/8000/100/sol8115.html

Hope I understood your question properly. 🙂

/Patrik