WebCam als schlanke alternative zum appVideoControl

src/snapshotService.js

@@ -0,0 +1,50 @@
+'use strict';
+
+const express = require('express');
+
+// Returns an Express router mounted at /api/snapshot
+// GET /api/snapshot          → JSON listing of cameras
+// GET /api/snapshot/cam0     → latest JPEG from cam0
+// GET /api/snapshot/cam1     → latest JPEG from cam1
+function createSnapshotRouter(streams) {
+  const router = express.Router();
+
+  router.get('/', (_req, res) => {
+    res.json({
+      cameras: streams.map((s, i) => ({
+        id:       `cam${i}`,
+        device:   s.device,
+        running:  s.isRunning,
+        clients:  s.clientCount,
+        hasFrame: s.latestFrame !== null,
+        url:      `/api/snapshot/cam${i}`,
+      })),
+    });
+  });
+
+  router.get('/:id', (req, res) => {
+    const idx = parseInt(req.params.id.replace('cam', ''), 10);
+    if (isNaN(idx) || !streams[idx]) {
+      return res.status(404).json({ error: 'camera not found' });
+    }
+
+    const frame = streams[idx].latestFrame;
+    if (!frame) {
+      return res.status(503).json({ error: 'no frame available yet – stream may still be starting' });
+    }
+
+    res.set({
+      'Content-Type':   'image/jpeg',
+      'Content-Length': frame.length,
+      'Cache-Control':  'no-store',
+      'X-Camera-Id':    `cam${idx}`,
+      'X-Camera-Device': streams[idx].device,
+      'X-Timestamp':    new Date().toISOString(),
+    });
+    res.end(frame);
+  });
+
+  return router;
+}
+
+module.exports = { createSnapshotRouter };