Add SPA episode navigation to avoid rerun WASM reload

positronic/server/positronic_server.py

@@ -103,6 +103,17 @@ async def cache_rerun_assets(request: Request, call_next):
     return response
 
 
+def _make_serializable(obj):
+    """Ensure obj is JSON serializable (e.g. convert datetime)."""
+    if isinstance(obj, datetime):
+        return obj.isoformat()
+    if isinstance(obj, dict):
+        return {k: _make_serializable(v) for k, v in obj.items()}
+    if isinstance(obj, list):
+        return [_make_serializable(v) for v in obj]
+    return obj
+
+
 def _iter_file_chunks(path: str, *, chunk_size: int = 128 * 1024):
     with open(path, 'rb') as source:
         while True:
@@ -188,16 +199,6 @@ async def episode_viewer(request: Request, episode_id: int):
     size_mb = meta.get('size_mb')
     size_mb_display = f'{size_mb:.2f}' if isinstance(size_mb, int | float) else None
 
-    # Ensure static_data is JSON serializable (e.g. handle datetime)
-    def _make_serializable(obj):
-        if isinstance(obj, datetime):
-            return obj.isoformat()
-        if isinstance(obj, dict):
-            return {k: _make_serializable(v) for k, v in obj.items()}
-        if isinstance(obj, list):
-            return [_make_serializable(v) for v in obj]
-        return obj
-
     return templates.TemplateResponse(
         'episode.html',
         {
@@ -428,6 +429,28 @@ async def api_dataset_status():
     }
 
 
+@app.get('/api/episode/{episode_id}')
+@require_dataset
+async def api_episode(episode_id: int):
+    ds = app_state.get('dataset')
+    try:
+        episode = ds[episode_id]
+    except IndexError as e:
+        raise HTTPException(status_code=404, detail='Episode not found') from e
+
+    meta = episode.meta
+    size_mb = meta.get('size_mb')
+
+    return {
+        'episode_id': episode_id,
+        'num_episodes': len(ds),
+        'task': episode.static.get('task', None),
+        'episode_path': meta.get('path'),
+        'episode_size_mb': f'{size_mb:.2f}' if isinstance(size_mb, int | float) else None,
+        'static_data': _make_serializable(episode.static),
+    }
+
+
 @app.get('/api/episode_rrd/{episode_id}')
 @require_dataset
 async def api_episode_rrd(episode_id: int):

positronic/server/static/app.js

@@ -615,6 +615,7 @@ function loadSidebarState() {
 
 function initializeSidebar(staticData) {
   const tbody = document.querySelector('.sidebar-content-wrapper tbody');
+  tbody.innerHTML = '';
 
   tbody.insertAdjacentHTML('beforeend', renderLevel('', staticData));
   document.querySelectorAll('.expand-button').forEach((button) => {

positronic/server/static/sw.js

@@ -0,0 +1,31 @@
+// Service Worker to cache rerun WASM and JS assets.
+// These files are large (~35MB WASM) and don't change between episodes.
+
+const CACHE_NAME = 'rerun-assets-v1';
+const RERUN_PATH_PREFIX = '/static/rerun/';
+
+self.addEventListener('install', () => self.skipWaiting());
+self.addEventListener('activate', (event) => {
+    event.waitUntil(
+        caches.keys().then((names) =>
+            Promise.all(names.filter((n) => n !== CACHE_NAME).map((n) => caches.delete(n)))
+        ).then(() => self.clients.claim())
+    );
+});
+
+self.addEventListener('fetch', (event) => {
+    const url = new URL(event.request.url);
+    if (!url.pathname.startsWith(RERUN_PATH_PREFIX)) return;
+
+    event.respondWith(
+        caches.open(CACHE_NAME).then((cache) =>
+            cache.match(event.request).then((cached) => {
+                if (cached) return cached;
+                return fetch(event.request).then((response) => {
+                    if (response.ok) cache.put(event.request, response.clone());
+                    return response;
+                });
+            })
+        )
+    );
+});

positronic/server/templates/base.html

@@ -28,6 +28,7 @@
     </div>
 
     <script src="/static/app.js"></script>
+    <script>if ('serviceWorker' in navigator) navigator.serviceWorker.register('/static/sw.js', {scope: '/static/'});</script>
     {% block scripts %}{% endblock %}
 </body>
 </html>