There are a lot of examples of implementing a TCP/IP-WS stack in all kinds of languages, also in PHP/CLI. But that is not what I'm looking for.
For http protocol there is Apache webserver software. It listens on default http port 80 for incoming requests. On shared hosting servers it can host an array of domain names and the incoming request url is mapped to the right served directory/file in the "hostAccountDir/domainName/docRoot/".
In this model each PHP script is a "specialized HTTP/application level" server; and does not need to invent/implement the TCP/IP-HTTP stack. Fortunately Apache does that for all PHP scripts.
Is there such a thing for Websockets, listening on port 9000(?), forking to the served directory/file... etc?