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PhotonVision/photon-thinclient/thinclient.html

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<!DOCTYPE html>
<html>
<head>
<title>ThinClient</title>
<style>
* {
margin: 0;
padding: 0;
}
.imgbox {
display: grid;
height: 100%;
width: 100%;
}
.center-fit {
width: 90vw;
margin: auto;
}
</style>
</head>
<body>
<hr>
<div class="imgbox">
<img id="streamImg" class="center-fit" src=''>
</div>
<hr>
<form id="frm1">
Host <input type="text" id="host" value="photonvision.local"><br>
Port <input type="text" id="port" value="1181"><br>
</form>
<button>Start Stream</button>
<script type="module">
class WebsocketVideoStream{
constructor(drawDiv, streamPort, host) {
this.drawDiv = drawDiv;
this.image = document.getElementById(this.drawDiv);
this.streamPort = streamPort;
this.serverAddr = "ws://" + host + "/websocket_cameras";
this.noStream = false;
this.noStreamPrev = false;
this.setNoStream();
this.ws_connect();
this.imgData = null;
this.imgDataTime = -1;
this.imgObjURL = null;
this.frameRxCount = 0;
requestAnimationFrame(()=>this.animationLoop());
}
animationLoop(){
var now = window.performance.now();
if((now - this.imgDataTime) > 2500 && this.imgData != null){
//Handle websocket send timeouts by restarting
this.setNoStream();
this.stopStream();
setTimeout(this.startStream.bind(this), 1000); //restart stream one second later
} else {
if(this.streamPort == null){
this.setNoStream();
} else if (this.imgData != null) {
//From https://stackoverflow.com/questions/67507616/set-image-src-from-image-blob/67507685#67507685
if(this.imgObjURL != null){
URL.revokeObjectURL(this.imgObjURL)
}
this.imgObjURL = URL.createObjectURL(this.imgData);
//Update the image with the new mimetype and image
this.image.src = this.imgObjURL;
this.noStream = false;
} else {
//Nothing, hold previous image while waiting for next frame
}
}
requestAnimationFrame(()=>this.animationLoop());
}
setNoStream() {
this.noStreamPrev = this.noStream;
this.noStream = true;
if(this.noStreamPrev == false && this.noStream == true){
//One-shot background change to preserve animation
this.image.src = "loading.gif";
}
}
startStream() {
if(this.serverConnectionActive == true && this.streamPort > 0){
this.ws.send(JSON.stringify({"cmd": "subscribe", "port":this.streamPort}));
this.noStream = false;
}
}
stopStream() {
if(this.serverConnectionActive == true && this.streamPort > 0){
this.ws.send(JSON.stringify({"cmd": "unsubscribe"}));
this.noStream = true;
}
}
setPort(streamPort){
this.stopStream();
this.frameRxCount = 0;
this.streamPort = streamPort;
this.startStream();
}
ws_onOpen() {
// Set the flag allowing general server communication
this.serverConnectionActive = true;
console.log("Connected!");
this.startStream();
}
ws_onClose(e) {
this.setNoStream();
//Clear flags to stop server communication
this.ws = null;
this.serverConnectionActive = false;
console.log('Camera Socket is closed. Reconnect will be attempted in 0.5 second.', e.reason);
setTimeout(this.ws_connect.bind(this), 500);
if(!e.wasClean){
console.error('Socket encountered error!');
}
}
ws_onError(e){
e; //prevent unused failure
this.ws.close();
}
ws_onMessage(e){
if(typeof e.data === 'string'){
//string data from host
//TODO - anything to recieve info here? Maybe "avaialble streams?"
} else {
if(e.data.size > 0){
//binary data - a frame
this.imgData = e.data;
this.imgDataTime = window.performance.now();
this.frameRxCount++;
} else {
//TODO - server is sending empty frames?
}
}
}
ws_connect() {
this.ws = new WebSocket(this.serverAddr);
this.ws.binaryType = "blob";
this.ws.onopen = this.ws_onOpen.bind(this);
this.ws.onmessage = this.ws_onMessage.bind(this);
this.ws.onclose = this.ws_onClose.bind(this);
this.ws.onerror = this.ws_onError.bind(this);
console.log("Connecting to server " + this.serverAddr);
}
ws_close(){
this.ws.close();
}
}
var stream = null;
function streamStartRequest() {
var host = document.getElementById("host").value + ":5800";
var port = document.getElementById("port").value;
if(stream == null){
stream = new WebsocketVideoStream("streamImg",port,host);
stream.startStream();
} else {
stream.setPort(port);
}
}
// Attach listener
document.querySelector('button').addEventListener('click', streamStartRequest);
// Deal with URLParams, validating inputs
const queryString = window.location.search;
const urlParams = new URLSearchParams(queryString);
const port_in = urlParams.get('port')
const host_in = urlParams.get('host')
if(port_in != ""){
document.getElementById("port").value = port_in;
}
if(host_in != ""){
document.getElementById("host").value = host_in;
}
if(port_in != "" & host_in != ""){
streamStartRequest(); //we got valid inputs, auto-start the stream
}
</script>
</body>
</html>