use GODEBUG=embedfollowsymlinks=1 to support symlinked web src files

app/web/scripts/clientsync.js

@@ -0,0 +1,43 @@
+import { getSetting, requestAPI } from "./utils.js";
+import { error } from "./dialog.js";
+
+export async function setupClientSync (callback) {
+	const scheme = getSetting("sync-scheme");
+	const rate = getSetting("sync-rate");
+	if (scheme === "never") {
+		return;
+	}
+	else if (scheme === "always") {
+		window.setInterval(callback, rate * 1000);
+	}
+	else if (scheme === "hash") {
+		const newHash = (await requestAPI("/sync/hash")).data;
+		localStorage.setItem("sync-current-hash", newHash);
+		window.setInterval(async () => {
+			const newHash = (await requestAPI("/sync/hash")).data;
+			if (localStorage.getItem("sync-current-hash") !== newHash) {
+				localStorage.setItem("sync-current-hash", newHash);
+				callback();
+			}
+		}, rate * 1000);
+	}
+	else if (scheme === "interrupt") {
+		const socket = new WebSocket(`wss://${window.API.replace("https://", "")}/sync/interrupt`);
+		socket.addEventListener("open", (_event) => {
+			socket.send(`rate ${rate}`);
+		});
+		socket.addEventListener("message", (event) => {
+			const message = event.data.toString();
+			if (message === "sync") {
+				callback();
+			}
+			else {
+				error("clientsync: recieved unexpected message from server, closing socket.");
+				socket.close();
+			}
+		});
+	}
+	else {
+		error(`clientsync: unsupported scheme ${scheme} selected.`);
+	}
+}