ProPresenter Look 1.0.0: server entry

modules/propresenter-looks/server.js

@@ -0,0 +1,242 @@
+'use strict';
+
+/**
+ * ProPresenter Look — server part.
+ *
+ * Polls ProPresenter's network API for the live audience look and fans it
+ * out to every tile over SSE. Browsers never talk to ProPresenter directly.
+ *
+ *   GET /state   → { state: <view> }   (instant paint for new tiles)
+ *   GET /stream  → SSE, `state` events (change-detected, heartbeated)
+ *
+ * ProPresenter's routes (ProPresenter 7.9+ / 20+):
+ *   GET /v1/look/current → { id: { uuid, name, index }, screens: [...] }
+ *   GET /v1/looks        → [ { id: { uuid, name, index }, screens: [...] }, … ]
+ * The current look carries a UUID of its own, never one from /v1/looks. Its
+ * `index` points at the saved look it matches, or equals the number of saved
+ * looks when someone has changed it by hand and it matches none.
+ */
+
+const POLL_MS = 1000; // the look matters the moment it changes
+const RETRY_MS = 3000; // while ProPresenter is unreachable
+const LOOKS_EVERY = 10; // re-read the saved looks every N polls
+const REQUEST_TIMEOUT_MS = 2500;
+
+/** SSE comment ping cadence — keeps idle connections alive through sleepy Wi-Fi. */
+const HEARTBEAT_MS = 15000;
+
+/** Set by init(), read by the routes — both are rebuilt together on remount. */
+let current = null;
+
+function emptyView(configured = false) {
+  return {
+    configured,
+    reachable: false,
+    lastError: '',
+    look: null, // { name, modified, screens }
+    changedAt: 0, // ms epoch the look last changed while we watched; 0 = unknown
+    updatedAt: 0, // ms epoch of the last good answer
+  };
+}
+
+function errorText(err) {
+  return String(err?.cause?.code || err?.code || err?.message || err || 'failed');
+}
+
+/** One look's name, trimmed — ProPresenter leaves the current look's name blank on some versions. */
+function lookName(entry) {
+  return String(entry?.id?.name ?? entry?.name ?? '').trim();
+}
+
+module.exports = {
+  init({ config, log }) {
+    const streams = new Set();
+    const ep = config.propresenter && typeof config.propresenter === 'object' ? config.propresenter : {};
+    const host = String(ep.host || '').trim();
+    const port = Number(ep.port) || 1025;
+    const password = String(config.password || '');
+    const configured = Boolean(host && port);
+
+    let view = emptyView(configured);
+    let lastFrame = '';
+    let saved = []; // names of the saved looks, in ProPresenter's order
+    let savedOk = false;
+    let tick = 0;
+    let stopped = false;
+    let pollTimer = null;
+
+    function url(target) {
+      const built = new URL(`http://${host}:${port}${target}`);
+      if (password) built.searchParams.set('password', password);
+      return built;
+    }
+
+    async function requestJson(target) {
+      const response = await fetch(url(target), {
+        headers: { Accept: 'application/json' },
+        signal: AbortSignal.timeout(REQUEST_TIMEOUT_MS),
+      });
+      if (!response.ok) {
+        const err = new Error(`ProPresenter ${response.status} ${response.statusText}`);
+        err.status = response.status;
+        throw err;
+      }
+      const text = await response.text();
+      return text ? JSON.parse(text) : null;
+    }
+
+    function broadcast() {
+      let frame;
+      try {
+        frame = JSON.stringify(view);
+      } catch {
+        return;
+      }
+      // Polls land every second whether anything changed or not; only real
+      // changes go out, so idle tiles stay idle.
+      if (frame === lastFrame) return;
+      lastFrame = frame;
+      const payload = `event: state\ndata: ${frame}\n\n`;
+      for (const res of streams) {
+        try {
+          res.write(payload);
+        } catch {
+          streams.delete(res);
+        }
+      }
+    }
+
+    async function refreshSaved() {
+      try {
+        const list = await requestJson('/v1/looks');
+        saved = Array.isArray(list) ? list.map(lookName) : [];
+        savedOk = true;
+      } catch (err) {
+        // An older ProPresenter without the list still answers look/current;
+        // the live look's own name is shown then.
+        if (err.status !== 404) throw err;
+        saved = [];
+        savedOk = false;
+      }
+    }
+
+    function resolveLook(live) {
+      const index = Number(live?.id?.index);
+      const own = lookName(live);
+      const screens = Array.isArray(live?.screens) ? live.screens.length : 0;
+      if (savedOk && Number.isInteger(index) && index >= 0 && index < saved.length) {
+        return { name: saved[index] || own || `Look ${index + 1}`, modified: false, screens };
+      }
+      // Changed by hand, matching no saved look.
+      const modified = savedOk && Number.isInteger(index) && index >= saved.length;
+      return { name: own || (modified ? 'Custom look' : 'Unnamed look'), modified, screens };
+    }
+
+    async function pollTick() {
+      if (stopped) return;
+      const next = { ...view };
+      try {
+        tick += 1;
+        if (tick % LOOKS_EVERY === 1 || !savedOk) await refreshSaved();
+        const live = await requestJson('/v1/look/current');
+        let look = resolveLook(live);
+        // A look saved since our last read: refresh the list now rather than
+        // calling it "Custom" for up to ten seconds.
+        if (look.modified && !view.look?.modified && tick % LOOKS_EVERY !== 1) {
+          await refreshSaved();
+          look = resolveLook(live);
+        }
+        const before = view.look;
+        if (before && (before.name !== look.name || before.modified !== look.modified)) {
+          next.changedAt = Date.now();
+          log(`look → ${look.name}${look.modified ? ' (modified)' : ''}`);
+        } else if (!before) {
+          log(`look is ${look.name}${look.modified ? ' (modified)' : ''}`);
+        }
+        next.look = look;
+        next.reachable = true;
+        next.lastError = '';
+        next.updatedAt = Date.now();
+      } catch (err) {
+        if (view.reachable) log(`ProPresenter unreachable: ${errorText(err)}`);
+        next.reachable = false;
+        next.lastError = errorText(err); // "ECONNREFUSED" beats fetch's "fetch failed"
+        tick = 0; // re-read the saved looks first when it comes back
+      }
+      if (stopped) return;
+      view = next;
+      broadcast();
+      pollTimer = setTimeout(pollTick, view.reachable ? POLL_MS : RETRY_MS);
+    }
+
+    if (configured) {
+      log(`following the live look on ${host}:${port}`);
+      pollTick();
+    } else {
+      log('no ProPresenter host configured — set one in /admin');
+    }
+
+    const heartbeat = setInterval(() => {
+      for (const res of streams) {
+        try {
+          res.write(': ping\n\n');
+        } catch {
+          streams.delete(res);
+        }
+      }
+    }, HEARTBEAT_MS);
+    heartbeat.unref?.();
+
+    current = { streams, getView: () => view };
+
+    return {
+      stop() {
+        stopped = true;
+        clearTimeout(pollTimer);
+        clearInterval(heartbeat);
+        for (const res of streams) {
+          try { res.end(); } catch { /* already gone */ }
+        }
+        streams.clear();
+        if (current && current.streams === streams) current = null;
+      },
+      health() {
+        if (!configured) return { status: 'error', message: 'No ProPresenter host configured' };
+        if (view.reachable) {
+          return { status: 'ok', message: `Live look on ${host}:${port}: ${view.look ? view.look.name : '—'}` };
+        }
+        return {
+          status: view.updatedAt || view.lastError ? 'error' : 'connecting',
+          message: view.lastError ? `ProPresenter unreachable: ${view.lastError}` : `Reaching ${host}:${port}…`,
+        };
+      },
+    };
+  },
+
+  routes() {
+    return {
+      'GET /state': (req, res) => {
+        res.writeHead(200, { 'Content-Type': 'application/json; charset=utf-8', 'Cache-Control': 'no-store' });
+        res.end(JSON.stringify({ state: current ? current.getView() : emptyView() }));
+      },
+
+      'GET /stream': (req, res) => {
+        res.writeHead(200, {
+          'Content-Type': 'text/event-stream; charset=utf-8',
+          'Cache-Control': 'no-cache, no-transform',
+          Connection: 'keep-alive',
+          'X-Accel-Buffering': 'no',
+        });
+        res.write('retry: 3000\n\n');
+        res.write(`event: state\ndata: ${JSON.stringify(current ? current.getView() : emptyView())}\n\n`);
+        if (!current) return void res.end();
+        const { streams } = current;
+        // A viewer that stops reading (locked tablet, sleeping laptop) must
+        // not queue frames forever; keepalive probes make the OS notice.
+        try { req.socket.setKeepAlive(true, 15000); } catch { /* gone */ }
+        streams.add(res);
+        req.on('close', () => streams.delete(res));
+      },
+    };
+  },
+};