Fix terminal session: better error handling, reliable state save

- Fix asyncio.get_event_loop() → get_running_loop() in PTY reader
- Add error logging for PTY spawn failures
- Add POST /api/session/state endpoint for sendBeacon (beforeunload)
- Use navigator.sendBeacon for reliable state save on page close
- Improve frontend error reporting when terminal creation fails

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/routers/session.py

@@ -2,10 +2,10 @@
 
 import logging
 
-from fastapi import APIRouter, Depends, HTTPException
+from fastapi import APIRouter, Depends, HTTPException, Request, Query
 from pydantic import BaseModel
 
-from backend.auth import get_current_user
+from backend.auth import get_current_user, decode_token
 from backend.sessions import manager
 
 router = APIRouter(prefix="/api/session", tags=["session"])
@@ -41,6 +41,8 @@ async def get_session(user: str = Depends(get_current_user)):
 @router.put("/state")
 async def save_state(
     state: DesktopState,
+    request: Request,
+    token: str = Query(default=None),
     user: str = Depends(get_current_user),
 ):
     """Save desktop state (open apps, active app, terminal tab info)."""
@@ -48,6 +50,25 @@ async def save_state(
     return {"ok": True}
 
 
+@router.post("/state")
+async def save_state_beacon(
+    request: Request,
+    token: str = Query(default=None),
+):
+    """Save desktop state via sendBeacon (POST with token in query param)."""
+    if not token:
+        raise HTTPException(401, "Missing token")
+    try:
+        payload = decode_token(token)
+    except Exception:
+        raise HTTPException(401, "Invalid token")
+    user = payload["sub"]
+    body = await request.json()
+    state = DesktopState(**body)
+    manager.save_state(user, state.model_dump())
+    return {"ok": True}
+
+
 # ---------------------------------------------------------------------------
 # Terminal endpoints
 # ---------------------------------------------------------------------------
@@ -64,7 +85,11 @@ async def create_terminal(
     user: str = Depends(get_current_user),
 ):
     """Create a new persistent terminal."""
-    terminal = manager.create_terminal(user, cols=req.cols, rows=req.rows)
+    try:
+        terminal = manager.create_terminal(user, cols=req.cols, rows=req.rows)
+    except Exception as e:
+        log.exception("Failed to create terminal for %s", user)
+        raise HTTPException(500, f"Failed to spawn terminal: {e}")
     return terminal.to_dict()
 
 

backend/sessions.py

@@ -64,7 +64,7 @@ class ManagedTerminal:
 
     async def _read_loop(self):
         """Background task: read PTY output → scrollback + attached WebSockets."""
-        loop = asyncio.get_event_loop()
+        loop = asyncio.get_running_loop()
         while self.alive:
             try:
                 raw = await loop.run_in_executor(None, lambda: self.pty.read(4096))
@@ -237,12 +237,18 @@ class SessionManager:
             "PATH": "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
         }
 
-        pty = PtyProcess.spawn(
-            [shell, "-l"],
-            dimensions=(rows, cols),
-            env=env,
-            cwd=home,
-        )
+        log.info("Spawning PTY for %s: shell=%s home=%s", username, shell, home)
+
+        try:
+            pty = PtyProcess.spawn(
+                [shell, "-l"],
+                dimensions=(rows, cols),
+                env=env,
+                cwd=home,
+            )
+        except Exception:
+            log.exception("Failed to spawn PTY for %s", username)
+            raise
 
         terminal_id = str(uuid.uuid4())[:8]
         terminal = ManagedTerminal(

frontend/js/apps/terminal.js

@@ -19,7 +19,11 @@
                 method: 'POST',
                 body: { cols: 120, rows: 30 },
             });
-            if (!res.ok) return null;
+            if (!res || !res.ok) {
+                const err = res ? await res.text().catch(() => 'unknown') : 'no response';
+                console.error('Failed to create terminal:', err);
+                return null;
+            }
             const data = await res.json();
             return attachToTerminal(data.terminal_id, data.title);
         } catch (e) {

frontend/js/atlus.js

@@ -522,9 +522,18 @@
         }
     });
 
-    // Save state before unload
+    // Save state before unload (use sendBeacon for reliability)
     window.addEventListener('beforeunload', () => {
-        _doSaveState();
+        const termApp = Atlus.apps.terminal;
+        const terminalTabs = (termApp && termApp.getTerminalIds)
+            ? termApp.getTerminalIds() : [];
+        const state = {
+            open_apps: Atlus.openApps.slice(),
+            active_app: Atlus.activeApp,
+            terminal_tabs: terminalTabs,
+        };
+        const blob = new Blob([JSON.stringify(state)], { type: 'application/json' });
+        navigator.sendBeacon('/api/session/state?token=' + TOKEN, blob);
     });
 
     // =====================================================================