Use server-side date filtering for device event history chart

The device event history chart previously fetched all events and filtered
client-side. This wires the existing created_from API parameter to the
frontend so filtering happens in the backend.

Also fixes a bug where the Today filter returned no results: rusqlite was
storing datetimes with a space separator ("YYYY-MM-DD HH:MM:SS+00:00")
while SQL filters used RFC 3339 with a T separator, causing string
comparisons to fail for same-day events. All datetime storage across
device_events, devices, and notifications is now consistently RFC 3339.
A migration converts existing records.

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

backend/database_migrations/06-rfc3339_datetimes/up.sql

@@ -0,0 +1,3 @@
+UPDATE device_events SET created_on = REPLACE(created_on, ' ', 'T') WHERE created_on LIKE '____-__-__ %';
+UPDATE devices SET last_seen = REPLACE(last_seen, ' ', 'T') WHERE last_seen LIKE '____-__-__ %';
+UPDATE notifications SET created_on = REPLACE(created_on, ' ', 'T') WHERE created_on LIKE '____-__-__ %';

backend/src/db/device_events.rs

@@ -13,7 +13,7 @@ pub fn insert(event: DeviceEvent) -> Result<i64, DbError> {
         "INSERT INTO device_events (mac_address, created_on, event_type, ipv4_address, vendor) VALUES (?1, ?2, ?3, ?4, ?5)",
         params![
             event.mac_address,
-            event.created_on,
+            event.created_on.to_rfc3339_opts(chrono::SecondsFormat::Nanos, false),
             event.event_type,
             event.ipv4_address,
             event.vendor
@@ -92,7 +92,7 @@ pub fn purge_older_than(cutoff: DateTime<Utc>) -> Result<usize, DbError> {
 
     match conn.execute(
         "DELETE FROM device_events WHERE created_on < ?1",
-        params![cutoff],
+        params![cutoff.to_rfc3339()],
     ) {
         Ok(count) => {
             debug!("Purged {} device event(s) older than {}", count, cutoff);

backend/src/db/devices.rs

@@ -27,30 +27,14 @@ pub fn list_devices(
         params.push(is_registered.into());
     };
     if let Some(last_seen_from) = last_seen_from {
-        debug!(
+        debug!("Adding filter last_seen>={}", last_seen_from.to_rfc3339());
-            "Adding filter last_seen>={}",
-            last_seen_from.format("%Y-%m-%d %H:%M:%S")
-        );
         sql_statement.push_str("AND last_seen>=? ");
-        params.push(
+        params.push(last_seen_from.to_rfc3339().into());
-            last_seen_from
-                .format("%Y-%m-%d %H:%M:%S")
-                .to_string()
-                .into(),
-        );
     };
     if let Some(last_seen_to) = last_seen_to {
-        debug!(
+        debug!("Adding filter last_seen<={}", last_seen_to.to_rfc3339());
-            "Adding filter last_seen<={}",
-            last_seen_to.format("%Y-%m-%d %H:%M:%S")
-        );
         sql_statement.push_str("AND last_seen<=? ");
-        params.push(
+        params.push(last_seen_to.to_rfc3339().into());
-            last_seen_to
-                .format("%Y-%m-%d %H:%M:%S")
-                .to_string()
-                .into(),
-        );
     };
     if let Some(owner) = owner {
         debug!("Adding filter owner={}", owner);
@@ -126,7 +110,7 @@ pub fn insert(device: Device) -> Result<(), DbError> {
 
     match conn.execute(
         "INSERT INTO devices (mac_address, ipv4_address, vendor, last_seen, is_registered, owner, device_type) VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7)",
-        params![device.mac_address, device.ipv4_address, device.vendor, device.last_seen, device.is_registered, device.owner, device.device_type]) {
+        params![device.mac_address, device.ipv4_address, device.vendor, device.last_seen.to_rfc3339_opts(chrono::SecondsFormat::Nanos, false), device.is_registered, device.owner, device.device_type]) {
             Ok(_) => {
                 debug!("Device inserted into database: {}", device);
                 Ok(())
@@ -145,7 +129,7 @@ pub fn update(device: Device) -> Result<(), DbError> {
         params![
             device.ipv4_address,
             device.vendor,
-            device.last_seen,
+            device.last_seen.to_rfc3339_opts(chrono::SecondsFormat::Nanos, false),
             device.is_registered,
             device.owner,
             device.device_type,

backend/src/db/notifications.rs

@@ -67,7 +67,7 @@ pub fn insert(notification: Notification) -> Result<i64, DbError> {
 
     match conn.execute(
             "INSERT INTO notifications (created_on, notification_type, title, body, is_new, mac_address) VALUES (?1, ?2, ?3, ?4, ?5, ?6)",
-            params![notification.created_on, notification.notification_type, notification.title, notification.body, notification.is_new, notification.mac_address]) {
+            params![notification.created_on.to_rfc3339_opts(chrono::SecondsFormat::Nanos, false), notification.notification_type, notification.title, notification.body, notification.is_new, notification.mac_address]) {
                 Ok(_) => {
                     debug!("Notification inserted into database: {}", notification);
                     Ok(conn.last_insert_rowid())
@@ -129,7 +129,7 @@ pub fn purge_older_than(cutoff: DateTime<Utc>) -> Result<usize, DbError> {
 
     match conn.execute(
         "DELETE FROM notifications WHERE created_on < ?1",
-        params![cutoff],
+        params![cutoff.to_rfc3339()],
     ) {
         Ok(count) => {
             debug!("Purged {} notification(s) older than {}", count, cutoff);

backend/tests/database_setup/01-notifications.sql

@@ -1,6 +1,6 @@
-INSERT INTO NOTIFICATIONS (id, created_on, notification_type, title, body, is_new) VALUES (1, '2026-01-03 14:13:12', 'NewDeviceFound', 'Unread new device found', 'Body unread new device found', 1);
+INSERT INTO NOTIFICATIONS (id, created_on, notification_type, title, body, is_new) VALUES (1, '2026-01-03T14:13:12+00:00', 'NewDeviceFound', 'Unread new device found', 'Body unread new device found', 1);
-INSERT INTO NOTIFICATIONS (id, created_on, notification_type, title, body, is_new) VALUES (2, '2026-01-04 08:10:13', 'NewDeviceFound', 'Read new device found', 'Body read new device found', 0);
+INSERT INTO NOTIFICATIONS (id, created_on, notification_type, title, body, is_new) VALUES (2, '2026-01-04T08:10:13+00:00', 'NewDeviceFound', 'Read new device found', 'Body read new device found', 0);
-INSERT INTO NOTIFICATIONS (id, created_on, notification_type, title, body, is_new) VALUES (3, '2026-01-05 17:20:01', 'DeviceOnlineAfterTime', 'Unread device online after time', 'Body unread device online after time', 1);
+INSERT INTO NOTIFICATIONS (id, created_on, notification_type, title, body, is_new) VALUES (3, '2026-01-05T17:20:01+00:00', 'DeviceOnlineAfterTime', 'Unread device online after time', 'Body unread device online after time', 1);
-INSERT INTO NOTIFICATIONS (id, created_on, notification_type, title, body, is_new) VALUES (4, '2026-01-06 02:11:12', 'DeviceOnlineAfterTime', 'Read device online after time', 'Body read device online after time', 0);
+INSERT INTO NOTIFICATIONS (id, created_on, notification_type, title, body, is_new) VALUES (4, '2026-01-06T02:11:12+00:00', 'DeviceOnlineAfterTime', 'Read device online after time', 'Body read device online after time', 0);
-INSERT INTO NOTIFICATIONS (id, created_on, notification_type, title, body, is_new) VALUES (5, '2026-02-01 11:11:11', 'Other', 'Unread other', 'Body other', 1);
+INSERT INTO NOTIFICATIONS (id, created_on, notification_type, title, body, is_new) VALUES (5, '2026-02-01T11:11:11+00:00', 'Other', 'Unread other', 'Body other', 1);
-INSERT INTO NOTIFICATIONS (id, created_on, notification_type, title, body, is_new) VALUES (6, '2026-02-03 13:13:13', 'Other', 'Read other', 'Body other', 0);
+INSERT INTO NOTIFICATIONS (id, created_on, notification_type, title, body, is_new) VALUES (6, '2026-02-03T13:13:13+00:00', 'Other', 'Read other', 'Body other', 0);

backend/tests/database_setup/02-devices.sql

@@ -1,6 +1,6 @@
 INSERT INTO DEVICES (mac_address, ipv4_address, vendor, last_seen, is_registered, owner, device_type)
-    VALUES ('aa:aa:aa:aa:aa:aa', '192.168.0.1', 'Vendor 1', '2026-01-01 11:11:11', 0, '', '');
+    VALUES ('aa:aa:aa:aa:aa:aa', '192.168.0.1', 'Vendor 1', '2026-01-01T11:11:11+00:00', 0, '', '');
 INSERT INTO DEVICES (mac_address, ipv4_address, vendor, last_seen, is_registered, owner, device_type)
-    VALUES ('bb:bb:bb:bb:bb:bb', '192.168.0.2', 'Vendor 2', '2026-02-03 13:14:15', 1, 'John', 'Phone');
+    VALUES ('bb:bb:bb:bb:bb:bb', '192.168.0.2', 'Vendor 2', '2026-02-03T13:14:15+00:00', 1, 'John', 'Phone');
 INSERT INTO DEVICES (mac_address, ipv4_address, vendor, last_seen, is_registered, owner, device_type)
-    VALUES ('cc:cc:cc:cc:cc:cc', '192.168.0.3', 'Vendor 3', '2026-02-17 20:11:00', 1, 'Sarah', 'Laptop');
+    VALUES ('cc:cc:cc:cc:cc:cc', '192.168.0.3', 'Vendor 3', '2026-02-17T20:11:00+00:00', 1, 'Sarah', 'Laptop');

backend/tests/database_setup/03-device_events.sql

@@ -1,6 +1,6 @@
 INSERT INTO device_events (id, mac_address, created_on, event_type, ipv4_address, vendor)
-    VALUES (1, 'aa:aa:aa:aa:aa:aa', '2026-01-01 11:11:11', 'NewDevice', '192.168.0.1', 'Vendor 1');
+    VALUES (1, 'aa:aa:aa:aa:aa:aa', '2026-01-01T11:11:11+00:00', 'NewDevice', '192.168.0.1', 'Vendor 1');
 INSERT INTO device_events (id, mac_address, created_on, event_type, ipv4_address, vendor)
-    VALUES (2, 'bb:bb:bb:bb:bb:bb', '2026-02-03 13:14:15', 'DeviceSeen', '192.168.0.2', 'Vendor 2');
+    VALUES (2, 'bb:bb:bb:bb:bb:bb', '2026-02-03T13:14:15+00:00', 'DeviceSeen', '192.168.0.2', 'Vendor 2');
 INSERT INTO device_events (id, mac_address, created_on, event_type, ipv4_address, vendor)
-    VALUES (3, 'aa:aa:aa:aa:aa:aa', '2026-03-10 09:00:00', 'DeviceSeen', '192.168.0.1', 'Vendor 1');
+    VALUES (3, 'aa:aa:aa:aa:aa:aa', '2026-03-10T09:00:00+00:00', 'DeviceSeen', '192.168.0.1', 'Vendor 1');

frontend/lib/devices/device_event_history.dart

@@ -70,7 +70,7 @@ class DeviceEventHistory extends StatefulWidget {
 }
 
 class _DeviceEventHistoryState extends State<DeviceEventHistory> {
-  List<DeviceEvent>? _allEvents;
+  List<DeviceEvent>? _events;
   bool _isLoading = true;
   String? _error;
   _TimeRange _selectedRange = _TimeRange.lastWeek;
@@ -89,10 +89,11 @@ class _DeviceEventHistoryState extends State<DeviceEventHistory> {
     try {
       final events = await BackendAPI.instance.getDeviceEvents(
         widget.device.macAddress,
+        createdFrom: _selectedRange.cutoff,
       );
       if (!mounted) return;
       setState(() {
-        _allEvents = events;
+        _events = events;
         _isLoading = false;
       });
     } catch (e) {
@@ -104,12 +105,6 @@ class _DeviceEventHistoryState extends State<DeviceEventHistory> {
     }
   }
 
-  List<DeviceEvent> get _filteredEvents {
-    if (_allEvents == null) return [];
-    final cutoff = _selectedRange.cutoff;
-    return _allEvents!.where((e) => e.createdOn.isAfter(cutoff)).toList();
-  }
-
   @override
   Widget build(BuildContext context) {
     if (_isLoading) {
@@ -126,7 +121,7 @@ class _DeviceEventHistoryState extends State<DeviceEventHistory> {
       );
     }
 
-    final events = _filteredEvents;
+    final events = _events ?? [];
 
     return Column(
       crossAxisAlignment: CrossAxisAlignment.start,
@@ -143,6 +138,7 @@ class _DeviceEventHistoryState extends State<DeviceEventHistory> {
             selected: {_selectedRange},
             onSelectionChanged: (selection) {
               setState(() => _selectedRange = selection.first);
+              _loadEvents();
             },
           ),
         ),

frontend/lib/utils/oott_api.dart

@@ -137,9 +137,19 @@ class BackendAPI {
     await _dio.delete('/devices/$macAddress');
   }
 
-  Future<List<DeviceEvent>> getDeviceEvents(String macAddress) async {
+  Future<List<DeviceEvent>> getDeviceEvents(
+    String macAddress, {
+    DateTime? createdFrom,
+  }) async {
     debugPrint('About to call GET /devices/$macAddress/events');
-    final response = await _dio.get('/devices/$macAddress/events');
+    final queryParams = <String, dynamic>{};
+    if (createdFrom != null) {
+      queryParams['created_from'] = createdFrom.toUtc().toIso8601String();
+    }
+    final response = await _dio.get(
+      '/devices/$macAddress/events',
+      queryParameters: queryParams.isEmpty ? null : queryParams,
+    );
     debugPrint('Received: ${response.data}');
     return (response.data as List)
         .map((item) => DeviceEvent.fromJson(item as Map<String, dynamic>))