PHP/JS Access SHOUTcast data and AJAX API

[Navalex]

Hello everyone,

I'm a web developer and my actual client wants me to create a website for his web radio.
He is using SHOUTcast V2 DNAS server on a Debian Stretch installation.

I already created a HTML5 player, and I made a PHP script that accesses to http://serverip:8000/admin.cgi?mode=...d=1&pass=xxxxx to get information like current playing song, history of played songs etc.

At this point, I have 2 questions that I can't find a solution.

1/ Actually, I need to call my PHP script each X seconds (approximately 5s) to refresh radio data. That will not be optimized for huge traffic. So I wanted to know if is there any solution to know when information as changed (like when a new song is playing)?

2/ I found this: http://wiki.winamp.com/wiki/SHOUTcas..._Specification and tried to access it with Postman (i just put the IPort, and op and seq parameter in header), and can't access to it. Someone can explain me how should i access to this API ?

Thanks,
Navalex.