loled/static/js/grab-canvas.js
2023-09-21 11:52:30 +02:00

53 lines
1.5 KiB
JavaScript

(async () => {
const globalConnnection = Symbol("grab-canvas-connection")
const currentScriptSrc = document.currentScript.src;
const sourceElt = document.querySelector("canvas,video");
if(!sourceElt){
console.error("No canvas found on this page")
}
const conn = new RTCPeerConnection({
iceServers: [
{urls: ["stun:stun.nextcloud.com:443"]}
]
});
const iceCandidates = []
conn.addEventListener("icecandidate", e => {
iceCandidates.push(e.candidate)
})
const allCandidatesCollected = new Promise(res =>
conn.addEventListener("icecandidate", e => e.candidate == null && res() ))
let captureFn = sourceElt.captureStream;
if(!captureFn){
captureFn = sourceElt.mozCaptureStream;
}
const canvasStream = captureFn()
const canvasStreamTracks = canvasStream.getVideoTracks()
if(canvasStreamTracks.length > 0){
conn.addTrack(canvasStreamTracks[0], canvasStream)
}
const offer = await conn.createOffer();
await conn.setLocalDescription(offer);
await allCandidatesCollected
const res = await fetch(new URL("/_loled/grab-display", currentScriptSrc), {
method: "POST",
headers: { "content-type": "application/json" },
body: JSON.stringify({
offer,
iceCandidates
})
})
const response = new RTCSessionDescription(await res.json());
conn.setRemoteDescription(response);
window[globalConnnection] = conn
})()