fix(logs): include ledmatrix-web logs in viewer and log subprocess stderr on failure

Two bugs conspired to produce "check the logs" toasts with an empty log viewer:

1. The log viewer (both SSE stream and REST endpoint) only queried
   ledmatrix.service via journalctl. Web API errors are logged by the
   Flask process running as ledmatrix-web.service, so they never
   appeared in the viewer. Add -u ledmatrix-web.service to both calls;
   also add --output=short-iso so timestamps from the two services
   sort cleanly when interleaved. Use shutil.which-resolved absolute
   paths for sudo/journalctl (S607 compliance) in api_v3.py; fall back
   to known Pi paths if which returns None.

2. app.py: resolve journalctl and systemctl to absolute paths via
   shutil.which at module init (_JOURNALCTL, _SYSTEMCTL). Replace bare
   names in logs_generator() and the cached systemctl is-active check.
   Guard both sites: logs_generator yields a clear SSE error message
   and sleeps 60 s if journalctl is not found; the systemctl block is
   skipped entirely if systemctl is not found, leaving the cache at its
   last-known value.

3. When execute_system_action() ran a systemctl command that returned
   non-zero, only the return code was logged — result.stderr was
   silently discarded. Log it at ERROR level and include returncode and
   stderr in the JSON response so callers get actionable failure details.
   Same fix applied to the early-return start_display branch.

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

src/wifi_manager.py

@@ -150,6 +150,18 @@ class WiFiManager:
         logger.info(f"WiFi Manager initialized - nmcli: {self.has_nmcli}, iwlist: {self.has_iwlist}, "
                    f"hostapd: {self.has_hostapd}, dnsmasq: {self.has_dnsmasq}, "
                    f"interface: {self._wifi_interface}, trixie: {self._is_trixie}")
+
+        # Once per process: remove a stale force-AP flag left by a prior crash.
+        # Guard with a class-level flag so the nmcli AP-state check only runs
+        # once even though WiFiManager is instantiated per-request.
+        if not WiFiManager._startup_cleanup_done:
+            WiFiManager._startup_cleanup_done = True
+            if self._FORCE_AP_FLAG_PATH.exists() and not self._is_ap_mode_active():
+                try:
+                    self._FORCE_AP_FLAG_PATH.unlink(missing_ok=True)
+                    logger.debug("Removed stale force-AP flag on startup (AP not active)")
+                except OSError as exc:
+                    logger.warning(f"Could not remove stale force-AP flag: {exc}")
     
     def _show_led_message(self, message: str, duration: int = 5):
         """
@@ -474,7 +486,10 @@ class WiFiManager:
                 if result.returncode == 0:
                     for line in result.stdout.strip().split('\n'):
                         if '/' in line:
-                            ip_address = line.split('/')[0].strip()
+                            # nmcli -t output is "IP4.ADDRESS[1]:x.x.x.x/prefix";
+                            # bare "x.x.x.x/prefix" is also accepted defensively.
+                            _, sep, rest = line.partition(':')
+                            ip_address = (rest if sep else line).split('/')[0].strip()
                             break
                 
                 # Final fallback: Get signal strength by matching SSID in WiFi list
@@ -500,6 +515,13 @@ class WiFiManager:
             
             # Check if AP mode is active
             ap_active = self._is_ap_mode_active()
+            # wlan0 shows as "connected" in AP mode; clear client-station fields so
+            # callers don't mistake the AP for an outbound WiFi connection.
+            if ap_active and wifi_connected:
+                wifi_connected = False
+                ssid = None
+                ip_address = None
+                logger.debug(f"{wlan_device} is in AP mode — overriding wifi_connected to False")
             
             return WiFiStatus(
                 connected=wifi_connected,
@@ -690,6 +712,10 @@ class WiFiManager:
     # ---------------------------------------------------------------------------
 
     _IP_FORWARD_SAVE_PATH = Path("/tmp/ledmatrix_ip_forward_saved")  # nosec B108 - process-specific named file; device is single-user RPi
+    # Written when AP mode is manually force-enabled; prevents daemon auto-disable
+    _FORCE_AP_FLAG_PATH = Path("/tmp/ledmatrix_force_ap_active")  # nosec B108 - process-specific named file; device is single-user RPi
+    # Ensures the startup stale-flag cleanup runs once per process, not per instantiation
+    _startup_cleanup_done: bool = False
 
     def _validate_ap_config(self) -> Tuple[str, int]:
         """Return a sanitized (ssid, channel) pair from config, falling back to defaults."""
@@ -1367,7 +1393,7 @@ class WiFiManager:
                         logger.error(f"Failed to restore original connection: {original_ssid}")
                         # Trigger AP mode as last resort
                         self._show_led_message("Enabling AP mode...", duration=5)
-                        ap_success, ap_msg = self.enable_ap_mode()
+                        ap_success, ap_msg = self.enable_ap_mode(force=True)
                         if ap_success:
                             logger.info("AP mode enabled as failsafe")
                             return False, "Connection failed and restoration failed. AP mode enabled."
@@ -1379,7 +1405,7 @@ class WiFiManager:
                 elif not success:
                     logger.warning(f"Connection to {ssid} failed and no original connection to restore")
                     self._show_led_message("Enabling AP mode...", duration=5)
-                    ap_success, ap_msg = self.enable_ap_mode()
+                    ap_success, ap_msg = self.enable_ap_mode(force=True)
                     if ap_success:
                         logger.info("AP mode enabled as failsafe")
                         return False, "Connection failed. AP mode enabled."
@@ -1400,7 +1426,7 @@ class WiFiManager:
                     logger.error(f"Failed to restore after exception: {restore_error}")
                     # Last resort: enable AP mode
                     try:
-                        self.enable_ap_mode()
+                        self.enable_ap_mode(force=True)
                     except Exception as ap_error:  # nosec B110 - last-resort; do not re-raise, but log for debugging
                         logger.error("Last-resort AP mode enable failed in recovery path: %s", ap_error, exc_info=True)
             return False, str(e)
@@ -1464,26 +1490,29 @@ class WiFiManager:
             # Show LED message
             self._show_led_message(f"Connecting to {ssid}...", duration=10)
             
-            # First, check if connection already exists and try to activate it
-            # NetworkManager connection names might not match SSID exactly, so search by SSID
-            check_result = subprocess.run(
-                ["nmcli", "-t", "-f", "NAME,802-11-wireless.ssid", "connection", "show"],
-                capture_output=True,
-                text=True,
-                timeout=5
+            # Find existing NM connection for this SSID.
+            # 802-11-wireless.ssid is not a valid column in 'nmcli connection show',
+            # so list all wifi connections then query each one's SSID individually.
+            list_result = subprocess.run(  # nosec B603 B607 - fixed args, no user input
+                ["nmcli", "-t", "-f", "NAME,TYPE", "connection", "show"],
+                capture_output=True, text=True, timeout=5
             )
-            
             existing_conn_name = None
-            if check_result.returncode == 0:
-                for line in check_result.stdout.strip().split('\n'):
-                    if ':' in line:
-                        parts = line.split(':')
-                        if len(parts) >= 2:
-                            conn_name = parts[0].strip()
-                            conn_ssid = parts[1].strip() if len(parts) > 1 else ""
-                            if conn_ssid == ssid:
-                                existing_conn_name = conn_name
-                                break
+            if list_result.returncode == 0:
+                for line in list_result.stdout.strip().split('\n'):
+                    if ':' not in line:
+                        continue
+                    parts = line.split(':')
+                    if len(parts) < 2 or parts[1].strip() != '802-11-wireless':
+                        continue
+                    conn_name = parts[0].strip()
+                    ssid_r = subprocess.run(  # nosec B603 B607 - conn_name from nmcli output, not user input
+                        ["nmcli", "-g", "802-11-wireless.ssid", "connection", "show", conn_name],
+                        capture_output=True, text=True, timeout=5
+                    )
+                    if ssid_r.returncode == 0 and ssid_r.stdout.strip() == ssid:
+                        existing_conn_name = conn_name
+                        break
             
             # Also try direct lookup by SSID (in case connection name matches SSID)
             if not existing_conn_name:
@@ -1855,7 +1884,7 @@ class WiFiManager:
         logger.warning(f"Failed to enable WiFi radio after {max_retries} attempts")
         return False
     
-    def enable_ap_mode(self) -> Tuple[bool, str]:
+    def enable_ap_mode(self, force: bool = False) -> Tuple[bool, str]:
         """
         Enable access point mode
         
@@ -1877,20 +1906,29 @@ class WiFiManager:
             if not self._ensure_wifi_radio_enabled():
                 return False, "WiFi radio is disabled and could not be enabled"
             
-            # Check if WiFi is connected
+            # Check if WiFi is connected (skip when force=True)
             status = self.get_wifi_status()
-            if status.connected:
+            if not force and status.connected:
                 return False, "Cannot enable AP mode while WiFi is connected"
             
-            # Check if Ethernet is connected
-            if self._is_ethernet_connected():
+            # Check if Ethernet is connected (skip when force=True)
+            if not force and self._is_ethernet_connected():
                 return False, "Cannot enable AP mode while Ethernet is connected"
             
+            if force:
+                logger.debug(f"enable_ap_mode: force=True — WiFi/Ethernet guards bypassed; will create {self._FORCE_AP_FLAG_PATH}")
+
             # Try hostapd/dnsmasq first (captive portal mode)
             if self.has_hostapd and self.has_dnsmasq:
                 result = self._enable_ap_mode_hostapd()
                 if result[0]:
                     self._ap_enabled_at = time.time()
+                    if force:
+                        try:
+                            self._FORCE_AP_FLAG_PATH.touch()
+                            logger.debug(f"Force-AP flag created: {self._FORCE_AP_FLAG_PATH}")
+                        except OSError as exc:
+                            logger.warning(f"Failed to create force-AP flag {self._FORCE_AP_FLAG_PATH}: {exc}")
                     return result
 
             # Fallback to nmcli hotspot (simpler, no captive portal)
@@ -1900,6 +1938,12 @@ class WiFiManager:
                 result = self._enable_ap_mode_nmcli_hotspot()
                 if result[0]:
                     self._ap_enabled_at = time.time()
+                    if force:
+                        try:
+                            self._FORCE_AP_FLAG_PATH.touch()
+                            logger.debug(f"Force-AP flag created: {self._FORCE_AP_FLAG_PATH}")
+                        except OSError as exc:
+                            logger.warning(f"Failed to create force-AP flag {self._FORCE_AP_FLAG_PATH}: {exc}")
                 return result
 
             return False, "No WiFi tools available (nmcli, hostapd, or dnsmasq required)"
@@ -2091,8 +2135,14 @@ class WiFiManager:
                 self._clear_led_message()
                 return False, "AP started but captive-portal redirect setup failed"
 
-            # Verify the AP is actually running
-            status = self._get_ap_status_nmcli()
+            # Verify the AP is actually running (retry up to 5x with 2s delay for NM async activation)
+            status = {}
+            for _attempt in range(5):
+                status = self._get_ap_status_nmcli()
+                if status.get('active'):
+                    break
+                logger.debug(f"AP verification attempt {_attempt + 1}/5 not yet active, waiting 2s")
+                time.sleep(2)
             if status.get('active'):
                 ip = status.get('ip', '192.168.4.1')
                 logger.info(f"AP mode confirmed active at {ip} (open network, no password)")
@@ -2290,6 +2340,7 @@ class WiFiManager:
                         logger.warning("WiFi radio may be disabled after nmcli AP cleanup")
 
                 self._ap_enabled_at = None
+                self._FORCE_AP_FLAG_PATH.unlink(missing_ok=True)
                 logger.info("AP mode disabled successfully")
                 return True, "AP mode disabled"
             except Exception as e:
@@ -2478,22 +2529,29 @@ address=/detectportal.firefox.com/192.168.4.1
                 else:
                     logger.warning(f"Failed to enable AP mode: {message}")
             elif not should_have_ap and ap_active:
-                # Should not have AP but do - disable AP mode
-                # Always disable if WiFi or Ethernet connects, regardless of auto_enable setting
-                if status.connected or ethernet_connected:
+                # Should not have AP but do - check if it was manually force-enabled
+                force_active = self._FORCE_AP_FLAG_PATH.exists()
+                if status.connected:
+                    # WiFi connected: always disable AP (user successfully configured WiFi)
                     success, message = self.disable_ap_mode()
                     if success:
-                        if status.connected:
-                            logger.info("Auto-disabled AP mode (WiFi connected)")
-                        elif ethernet_connected:
-                            logger.info("Auto-disabled AP mode (Ethernet connected)")
-                        self._disconnected_checks = 0  # Reset counter
+                        logger.info("Auto-disabled AP mode (WiFi connected)")
+                        self._disconnected_checks = 0
                         return True
                     else:
                         logger.warning(f"Failed to auto-disable AP mode: {message}")
+                elif ethernet_connected and not force_active:
+                    # Ethernet connected, AP not manually forced: auto-disable
+                    success, message = self.disable_ap_mode()
+                    if success:
+                        logger.info("Auto-disabled AP mode (Ethernet connected)")
+                        self._disconnected_checks = 0
+                        return True
+                    else:
+                        logger.warning(f"Failed to auto-disable AP mode: {message}")
+                elif ethernet_connected and force_active:
+                    logger.debug("AP mode is force-active; Ethernet connected but auto-disable suppressed")
                 elif not auto_enable:
-                    # AP is active but auto_enable is disabled - this means it was manually enabled
-                    # Don't disable it automatically, let it stay active
                     logger.debug("AP mode is active (manually enabled), keeping active")
 
             # Idle-timeout check: disable AP if no client has connected within the window.

web_interface/app.py

@@ -2,8 +2,11 @@ from flask import Flask, request, redirect, url_for, jsonify, Response, send_fro
 import json
 import logging
 import os
+import queue
+import shutil
 import sys
 import subprocess
+import threading
 import time
 from pathlib import Path
 from datetime import datetime, timedelta
@@ -22,6 +25,9 @@ from src.plugin_system.state_manager import PluginStateManager
 from src.plugin_system.operation_history import OperationHistory
 from src.plugin_system.health_monitor import PluginHealthMonitor
 
+_JOURNALCTL = shutil.which('journalctl')
+_SYSTEMCTL = shutil.which('systemctl')
+
 # Create Flask app
 app = Flask(__name__)
 app.secret_key = os.urandom(24)
@@ -413,13 +419,53 @@ def add_security_headers(response):
     
     return response
 
-# SSE helper function
-def sse_response(generator_func):
-    """Helper to create SSE responses"""
-    def generate():
-        for data in generator_func():
-            yield f"data: {json.dumps(data)}\n\n"
-    return Response(generate(), mimetype='text/event-stream')
+class _StreamBroadcaster:
+    """Fan-out broadcaster: one background generator thread pushes to all SSE clients.
+
+    This means N browser tabs share one generator instead of each running their own,
+    keeping PIL encodes / subprocess forks constant regardless of how many tabs are open.
+    """
+
+    def __init__(self, generator_factory):
+        self._generator_factory = generator_factory
+        self._clients: set = set()
+        self._lock = threading.Lock()
+        self._thread: threading.Thread | None = None
+
+    def subscribe(self) -> queue.Queue:
+        q: queue.Queue = queue.Queue(maxsize=5)
+        with self._lock:
+            self._clients.add(q)
+            if not (self._thread and self._thread.is_alive()):
+                self._thread = threading.Thread(target=self._broadcast, daemon=True)
+                self._thread.start()
+        return q
+
+    def unsubscribe(self, q: queue.Queue) -> None:
+        with self._lock:
+            self._clients.discard(q)
+
+    def _broadcast(self):
+        for data in self._generator_factory():
+            with self._lock:
+                if not self._clients:
+                    # No subscribers — exit so the thread doesn't spin indefinitely.
+                    # subscribe() will restart it when a new client arrives.
+                    break
+                for q in self._clients:
+                    try:
+                        q.put_nowait(data)
+                    except queue.Full:
+                        # Client is reading too slowly; drop the oldest item and
+                        # deliver the latest so the queue never stalls the client.
+                        try:
+                            q.get_nowait()
+                        except queue.Empty:
+                            pass
+                        try:
+                            q.put_nowait(data)
+                        except queue.Full:
+                            pass
 
 # System status generator for SSE
 def system_status_generator():
@@ -450,12 +496,13 @@ def system_status_generator():
             # Check if display service is running (cached to avoid per-client subprocess forks)
             now = time.time()
             if (now - _ledmatrix_service_cache['timestamp']) >= _LEDMATRIX_SERVICE_CACHE_TTL:
-                try:
-                    result = subprocess.run(['systemctl', 'is-active', 'ledmatrix'],
-                                            capture_output=True, text=True, timeout=2)
-                    _ledmatrix_service_cache['active'] = result.stdout.strip() == 'active'
-                except (subprocess.SubprocessError, OSError):
-                    pass
+                if _SYSTEMCTL:
+                    try:
+                        result = subprocess.run([_SYSTEMCTL, 'is-active', 'ledmatrix'],
+                                                capture_output=True, text=True, timeout=2)
+                        _ledmatrix_service_cache['active'] = result.stdout.strip() == 'active'
+                    except (subprocess.SubprocessError, OSError):
+                        pass
                 _ledmatrix_service_cache['timestamp'] = now
             service_active = _ledmatrix_service_cache['active']
             
@@ -547,8 +594,13 @@ def logs_generator():
             # Get recent logs from journalctl (simplified version)
             # Note: User should be in systemd-journal group to read logs without sudo
             try:
+                if not _JOURNALCTL:
+                    yield {'timestamp': time.time(), 'logs': 'journalctl not found; cannot read logs'}
+                    time.sleep(60)
+                    continue
                 result = subprocess.run(
-                    ['journalctl', '-u', 'ledmatrix.service', '-n', '50', '--no-pager'],
+                    [_JOURNALCTL, '-u', 'ledmatrix.service', '-u', 'ledmatrix-web.service',
+                     '-n', '50', '--no-pager', '--output=short-iso'],
                     capture_output=True, text=True, timeout=5
                 )
 
@@ -564,7 +616,7 @@ def logs_generator():
                         # No logs available
                         logs_data = {
                             'timestamp': time.time(),
-                            'logs': 'No logs available from ledmatrix service'
+                            'logs': 'No logs available from ledmatrix or ledmatrix-web service'
                         }
                         yield logs_data
                 else:
@@ -596,20 +648,50 @@ def logs_generator():
 
         time.sleep(5)  # Update every 5 seconds (reduced frequency for better performance)
 
+# One broadcaster per stream — shared across all SSE clients
+_stats_broadcaster = _StreamBroadcaster(system_status_generator)
+_display_broadcaster = _StreamBroadcaster(display_preview_generator)
+_logs_broadcaster = _StreamBroadcaster(logs_generator)
+
+
+def _sse_stream(broadcaster: _StreamBroadcaster) -> Response:
+    """Return a streaming SSE response backed by a shared broadcaster."""
+    q = broadcaster.subscribe()
+
+    def generate():
+        try:
+            while True:
+                try:
+                    data = q.get(timeout=30)
+                    yield f"data: {json.dumps(data)}\n\n"
+                except queue.Empty:
+                    # Send an SSE comment heartbeat to keep the connection alive
+                    # through proxies that close idle connections.
+                    yield ": heartbeat\n\n"
+        except GeneratorExit:
+            pass
+        finally:
+            broadcaster.unsubscribe(q)
+
+    return Response(generate(), mimetype='text/event-stream')
+
+
 # SSE endpoints
 @app.route('/api/v3/stream/stats')
 def stream_stats():
-    return sse_response(system_status_generator)
+    return _sse_stream(_stats_broadcaster)
 
 @app.route('/api/v3/stream/display')
 def stream_display():
-    return sse_response(display_preview_generator)
+    return _sse_stream(_display_broadcaster)
 
 @app.route('/api/v3/stream/logs')
 def stream_logs():
-    return sse_response(logs_generator)
+    return _sse_stream(_logs_broadcaster)
 
-# Exempt SSE streams from CSRF and add rate limiting
+# Exempt SSE streams from CSRF and apply a generous rate limit.
+# SSE connections are long-lived HTTP requests, not repeated API calls, so the
+# tight "20 per minute" default would be exhausted quickly on reconnects.
 if csrf:
     csrf.exempt(stream_stats)
     csrf.exempt(stream_display)
@@ -617,9 +699,9 @@ if csrf:
     # Note: api_v3 blueprint is exempted above after registration
 
 if limiter:
-    limiter.limit("20 per minute")(stream_stats)
-    limiter.limit("20 per minute")(stream_display)
-    limiter.limit("20 per minute")(stream_logs)
+    limiter.limit("200 per minute")(stream_stats)
+    limiter.limit("200 per minute")(stream_display)
+    limiter.limit("200 per minute")(stream_logs)
 
 # Main route - redirect to v3 interface as default
 @app.route('/')

web_interface/blueprints/api_v3.py

@@ -4,6 +4,7 @@ import os
 import re
 import stat
 import sys
+import shutil
 import subprocess
 import tempfile
 import time
@@ -25,6 +26,9 @@ from src.web_interface.validators import (
 )
 from src.error_aggregator import get_error_aggregator
 
+_SUDO = shutil.which('sudo')
+_JOURNALCTL = shutil.which('journalctl')
+
 # Will be initialized when blueprint is registered
 config_manager = None
 plugin_manager = None
@@ -1459,10 +1463,16 @@ def execute_system_action():
                 result = subprocess.run(['sudo', 'systemctl', 'start', 'ledmatrix'],
                                      capture_output=True, text=True)
                 logger.info("start_display (%s) returned code %d", mode, result.returncode)
-                return jsonify({
+                if result.returncode != 0 and result.stderr:
+                    logger.error("start_display (%s) stderr: %s", mode, result.stderr.strip())
+                resp = {
                     'status': 'success' if result.returncode == 0 else 'error',
                     'message': 'Display started' if result.returncode == 0 else 'Failed to start display',
-                })
+                }
+                if result.returncode != 0:
+                    resp['returncode'] = result.returncode
+                    resp['stderr'] = result.stderr.strip()
+                return jsonify(resp)
             else:
                 result = subprocess.run(['sudo', 'systemctl', 'start', 'ledmatrix'],
                                      capture_output=True, text=True)
@@ -1564,10 +1574,16 @@ def execute_system_action():
             return jsonify({'status': 'error', 'message': 'Unknown action'}), 400
 
         logger.info("system action '%s' returncode=%d", action, result.returncode)
-        return jsonify({
+        if result.returncode != 0 and result.stderr:
+            logger.error("system action '%s' stderr: %s", action, result.stderr.strip())
+        resp = {
             'status': 'success' if result.returncode == 0 else 'error',
             'message': 'Action completed' if result.returncode == 0 else 'Action failed; check logs for details',
-        })
+        }
+        if result.returncode != 0:
+            resp['returncode'] = result.returncode
+            resp['stderr'] = result.stderr.strip()
+        return jsonify(resp)
 
     except Exception as e:
         logger.error("execute_system_action failed: %s", e, exc_info=True)
@@ -6425,9 +6441,12 @@ def list_plugin_assets():
 def get_logs():
     """Get system logs from journalctl"""
     try:
+        if not _SUDO or not _JOURNALCTL:
+            return jsonify({'status': 'error', 'message': 'sudo or journalctl not found on this system'}), 503
         # Get recent logs from journalctl
         result = subprocess.run(
-            ['sudo', 'journalctl', '-u', 'ledmatrix.service', '-n', '100', '--no-pager'],
+            [_SUDO, _JOURNALCTL, '-u', 'ledmatrix.service', '-u', 'ledmatrix-web.service',
+             '-n', '100', '--no-pager', '--output=short-iso'],
             capture_output=True,
             text=True,
             timeout=5
@@ -6438,7 +6457,7 @@ def get_logs():
             return jsonify({
                 'status': 'success',
                 'data': {
-                    'logs': logs_text if logs_text else 'No logs available from ledmatrix service'
+                    'logs': logs_text if logs_text else 'No logs available from ledmatrix or ledmatrix-web service'
                 }
             })
         else:
@@ -6542,7 +6561,7 @@ def scan_wifi_networks():
         ap_was_active = wifi_manager._is_ap_mode_active()
 
         # Perform the scan (this will handle AP mode disabling/enabling internally)
-        networks = wifi_manager.scan_networks()
+        networks, _was_cached = wifi_manager.scan_networks()
 
         # Convert to dict format
         networks_data = [
@@ -6680,7 +6699,9 @@ def enable_ap_mode():
         from src.wifi_manager import WiFiManager
 
         wifi_manager = WiFiManager()
-        success, message = wifi_manager.enable_ap_mode()
+        _force_raw = (request.get_json(silent=True) or {}).get('force', False)
+        force = _force_raw is True or (isinstance(_force_raw, str) and _force_raw.lower() in ('true', '1'))
+        success, message = wifi_manager.enable_ap_mode(force=force)
 
         if success:
             return jsonify({

web_interface/static/v3/app.js

@@ -1,4 +1,4 @@
-/* global showNotification, updateSystemStats, htmx */
+/* global showNotification, updateSystemStats, updateDisplayPreview, htmx */
 // LED Matrix v3 JavaScript
 // Additional helpers for HTMX and Alpine.js integration
 
@@ -51,7 +51,8 @@ document.body.addEventListener('htmx:afterRequest', function(event) {
     }
 });
 
-// SSE reconnection helper
+// SSE reconnection helper — closes and reopens both SSE streams,
+// reattaching the open/error handlers defined in base.html.
 window.reconnectSSE = function() {
     if (window.statsSource) {
         window.statsSource.close();
@@ -60,14 +61,18 @@ window.reconnectSSE = function() {
             const data = JSON.parse(event.data);
             if (typeof updateSystemStats === 'function') updateSystemStats(data);
         };
+        if (window._statsOpenHandler) window.statsSource.addEventListener('open', window._statsOpenHandler);
+        if (window._statsErrorHandler) window.statsSource.addEventListener('error', window._statsErrorHandler);
     }
 
     if (window.displaySource) {
         window.displaySource.close();
         window.displaySource = new EventSource('/api/v3/stream/display');
-        window.displaySource.onmessage = function() {
-            // Handle display updates
+        window.displaySource.onmessage = function(event) {
+            const data = JSON.parse(event.data);
+            if (typeof updateDisplayPreview === 'function') updateDisplayPreview(data);
         };
+        if (window._displayErrorHandler) window.displaySource.addEventListener('error', window._displayErrorHandler);
     }
 };
 

web_interface/templates/v3/base.html

@@ -1370,34 +1370,64 @@
 
     <!-- SSE connection for real-time updates -->
     <script>
-        // Connect to SSE streams
-        const statsSource = new EventSource('/api/v3/stream/stats');
-        const displaySource = new EventSource('/api/v3/stream/display');
+        // Assign to window so reconnectSSE() in app.js can reach them.
+        window.statsSource = new EventSource('/api/v3/stream/stats');
+        window.displaySource = new EventSource('/api/v3/stream/display');
 
-        statsSource.onmessage = function(event) {
+        window.statsSource.onmessage = function(event) {
             const data = JSON.parse(event.data);
             updateSystemStats(data);
         };
 
-        displaySource.onmessage = function(event) {
+        window.displaySource.onmessage = function(event) {
             const data = JSON.parse(event.data);
             updateDisplayPreview(data);
         };
 
-        // Connection status
-        statsSource.addEventListener('open', function() {
-            document.getElementById('connection-status').innerHTML = `
-                <div class="w-2 h-2 bg-green-500 rounded-full"></div>
-                <span class="text-gray-600">Connected</span>
-            `;
-        });
+        function _setConnectionStatus(connected, reconnecting) {
+            const el = document.getElementById('connection-status');
+            if (!el) return;
+            if (connected) {
+                el.innerHTML = `
+                    <div class="w-2 h-2 bg-green-500 rounded-full"></div>
+                    <span class="text-gray-600">Connected</span>
+                `;
+            } else if (reconnecting) {
+                el.innerHTML = `
+                    <div class="w-2 h-2 bg-yellow-500 rounded-full animate-pulse"></div>
+                    <span class="text-gray-600">Reconnecting…</span>
+                `;
+            } else {
+                el.innerHTML = `
+                    <div class="w-2 h-2 bg-red-500 rounded-full"></div>
+                    <span class="text-gray-600" title="Connection lost — try refreshing the page">Disconnected</span>
+                `;
+            }
+        }
 
-        statsSource.addEventListener('error', function() {
-            document.getElementById('connection-status').innerHTML = `
-                <div class="w-2 h-2 bg-red-500 rounded-full"></div>
-                <span class="text-gray-600">Disconnected</span>
-            `;
-        });
+        var _statsErrorCount = 0;
+
+        // Named on window so reconnectSSE() in app.js can reattach them after
+        // replacing the EventSource instances.
+        window._statsOpenHandler = function() {
+            _statsErrorCount = 0;
+            _setConnectionStatus(true, false);
+        };
+        window._statsErrorHandler = function() {
+            _statsErrorCount++;
+            // EventSource readyState 0 = CONNECTING (auto-retrying), 2 = CLOSED
+            var reconnecting = window.statsSource.readyState === EventSource.CONNECTING;
+            _setConnectionStatus(false, reconnecting && _statsErrorCount <= 3);
+        };
+        window._displayErrorHandler = function() {
+            // Display stream errors don't change the status badge but log to console
+            // so failures aren't completely silent.
+            console.warn('LEDMatrix: display preview stream error (readyState=' + window.displaySource.readyState + ')');
+        };
+
+        window.statsSource.addEventListener('open', window._statsOpenHandler);
+        window.statsSource.addEventListener('error', window._statsErrorHandler);
+        window.displaySource.addEventListener('error', window._displayErrorHandler);
 
         function updateSystemStats(data) {
             // Update CPU in header