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import { WebSocketServer } from 'ws';
const port = Number(process.env.PORT || 8080);
const profile = process.env.TIMEPLOT_PROFILE || 'telemetry';
const sendIntervalMs = Number(process.env.TIMEPLOT_INTERVAL_MS || 100);
const logEvery = Number(process.env.TIMEPLOT_LOG_EVERY || 10);
const wss = new WebSocketServer({ port });
const startedAt = Date.now();
let sampleIndex = 0;
let activeClientCount = 0;
function log(message, details = '') {
const timestamp = new Date().toISOString();
if (details) {
console.log(`[timeplot-ws ${timestamp}] ${message} ${details}`);
return;
}
console.log(`[timeplot-ws ${timestamp}] ${message}`);
}
function sampleTelemetry(seconds) {
return Math.sin(seconds * 2.2) + 0.35 * Math.cos(seconds * 6.4 + Math.sin(seconds * 0.8)) + 0.15 * Math.sin(seconds * 0.33);
}
function sampleChirp(seconds) {
return 0.7 * Math.sin(seconds * seconds * 1.4) + 0.3 * Math.sin(seconds * 7.5);
}
function sampleSteps(seconds) {
const phase = Math.floor((seconds % 8) / 1.0);
return [0, 0.4, 0.9, 1.2, 0.2, -0.6, -1.0, 0.3][phase] ?? 0;
}
function sampleBurst(seconds) {
const burstPhase = (seconds % 6) - 1.5;
const burst = Math.sin(seconds * 9.5) * Math.exp(-(burstPhase ** 2) * 0.8);
return 0.45 * Math.sin(seconds * 2.1) + burst;
}
function sampleValue(seconds) {
switch (profile) {
case 'chirp':
return sampleChirp(seconds);
case 'steps':
return sampleSteps(seconds);
case 'burst':
return sampleBurst(seconds);
case 'telemetry':
default:
return sampleTelemetry(seconds);
}
}
function buildMessage() {
const timestampMs = Date.now() - startedAt;
const seconds = timestampMs / 1000;
sampleIndex += 1;
return {
timestampMs,
value: Number(sampleValue(seconds).toFixed(6)),
sequence: sampleIndex,
profile,
};
}
const interval = setInterval(() => {
const message = buildMessage();
const payload = JSON.stringify(message);
let sentCount = 0;
for (const client of wss.clients) {
if (client.readyState === client.OPEN) {
client.send(payload);
sentCount += 1;
}
}
if (message.sequence === 1 || (logEvery > 0 && message.sequence % logEvery === 0)) {
log(
'broadcast',
`seq=${message.sequence} clients=${sentCount} timestampMs=${message.timestampMs} value=${message.value}`,
);
}
}, sendIntervalMs);
wss.on('connection', (socket, request) => {
const clientAddress = request.socket.remoteAddress || 'unknown';
activeClientCount += 1;
log('client connected', `from=${clientAddress} activeClients=${activeClientCount}`);
socket.send(JSON.stringify({
timestampMs: 0,
value: 0,
sequence: 0,
profile,
message: 'connected',
}));
socket.on('error', (error) => {
log('client error', `from=${clientAddress} error=${error.message}`);
});
socket.on('close', () => {
activeClientCount = Math.max(0, activeClientCount - 1);
log('client disconnected', `from=${clientAddress} activeClients=${activeClientCount}`);
});
});
wss.on('error', (error) => {
log('server error', error.message);
});
wss.on('listening', () => {
log('listening', `url=ws://localhost:${port}`);
log('config', `profile=${profile} intervalMs=${sendIntervalMs} logEvery=${logEvery}`);
});
function shutdown() {
log('shutdown requested', `activeClients=${activeClientCount}`);
clearInterval(interval);
wss.close(() => {
log('server stopped');
process.exit(0);
});
}
process.on('SIGINT', shutdown);
process.on('SIGTERM', shutdown);
|
