i have tried many WebSocket libraries (mWebSockets, WebSockets, WebSockets_Generic, WebSocket2_Generic) , but none compiles on the Giga Wifi.
Has anyone a clue ?
Thx
Hello,
Would you care to explain why you need this please? 
Simply to send new data from a local webserver (on the Giga) to web clients, and allow for clients feedback...
I found this video which is not in English but the images, codes and subtitles should do it for you, hope so^^
Tell me if this fits your need
Thx for the link. They use AJAX, which is a possible way to go. There are many web tech pages around discussing the pros and cons of AJAX vs WebSockets.
But, having played with WebSockets (with the library mWebSockets on the Arduino Uno R4 WiFi), I think it is really nicer.
For example, with WebSockets, when your Arduino server has new data of any kind, it will simply broadcast it immediately to all clients. Very low latency. With AJAX, each client has to explicitely ask for a refresh to see the new data.
Sorry, it seems like my skills in WebServer or whatever are below yours xD
You know more than me, I won't be able to help you furthermore.
However, you could make a Java functio that would automatically call itself every (let's say) 5 seconds in order to get the update
This is a work around I'm using with a ESP32. I don't even know what WebSockets are for but at this point I'll go take a look
Yes, take a look. There are libraries for the ESP32 as well as for the ESP8266, with many examples. It's a good point for the ESP's.
With a websocket connection opened, a web page may really become a control panel for your device. At any time both sides may initiate a data transfer.
There is a websocket lib for the Portenta H7, which has AFAIK the same proc and the same wifi module as the Giga, but not the same architecture... So it should not be so far away.