How to make friends socket.io and php?

Question

PHP

Good afternoon, you need to implement something like this.
There is a playlist.html file that sends json with a playlist to the server socket, then the socket must process the data (enter it into the mysql database) and send it to the client.
In fact, everything is elementary, but the problem is how the server connects to mysql (yes, I know that there is such a possibility), but I still need it to be able to process wordpress functions, update additional fields there, create posts from an array, and so on.
You can send it to the client and process it there, but if there is no one online, then naturally nothing will be processed.
Therefore, can anyone advise how to implement all this business?
Now, if he could connect to a php file, it would be great