fix(session-sharing): use the linked server for desktop meetings and links (#1507)

plugins/session-sharing/src/frontend/meeting-backend.ts

@@ -0,0 +1,44 @@
+import type { TermixApp } from "@termix/plugin-sdk/frontend";
+import { createMeetingApi } from "./meeting-api";
+
+export type MeetingBackend = Awaited<ReturnType<typeof connectMeetings>>;
+
+/** A room, its hosts and its sockets must all belong to the same backend. */
+export async function connectMeetings(app: TermixApp) {
+  const remoteUrl = app.desktop.available
+    ? await app.desktop.remoteServerUrl()
+    : null;
+  const key = remoteUrl?.replace(/\/+$/, "") || "local";
+  const origin = remoteUrl ? ("remote" as const) : ("local" as const);
+  const publicUrl =
+    remoteUrl || (!app.desktop.available ? window.location.href : null);
+  const assertCurrent = async () => {
+    const current = app.desktop.available
+      ? await app.desktop.remoteServerUrl()
+      : null;
+    if ((current?.replace(/\/+$/, "") || "local") !== key) {
+      throw new Error(app.t("collab.serverChanged"));
+    }
+  };
+  return {
+    key,
+    origin,
+    publicUrl,
+    assertCurrent,
+    api: createMeetingApi(app.apiFor(origin), assertCurrent),
+  };
+}
+
+export function meetingGuestUrl(
+  publicUrl: string | null,
+  token: string,
+): string | null {
+  if (!publicUrl) return null;
+  const url = new URL(publicUrl);
+  if (url.protocol !== "http:" && url.protocol !== "https:") return null;
+  url.search = "";
+  url.hash = "";
+  url.searchParams.set("view", "collab-guest");
+  url.searchParams.set("token", token);
+  return url.toString();
+}