Qtoggleserver

* core/history: Timesamped samples are now cached for faster access.
* core/main: The update routine is now properly synchronized with locks.
* core/ports: Reading values is now properly synchronized with locks.
* core/ports: Saving ports now properly synchronized with locks.
* core/slaves: Saving devices now properly synchronized with locks.
* frontend/cache: Fixed main device polling on settings page.
* frontend/dashboard: Added customizable number of digits to Line and Bar Chart widgets.
* frontend/dashboard: Panel changes are now properly detected when reconnected.
* frontend/widgets: Various Pie Chart readability improvements.

version-0.24.0-beta.2

* core/expressions: Time-processing expressions now ignore values when detecting a jump in system date/time.
* core/history: Last sampling timestamp is now persisted.
* core/history: Samples are no longer sampled unless system as real date/time.
* core/main: Fixed error when looping over ports.
* frontend/dashboard: Min, max and unit fields of chart widgets are now automatically set from selected port.
* frontend/dashboard: Chart widgets no longer block touch events on mobile.
* frontend/dashboard: Historical chart data is no longer refreshed unless panel is active.
* frontend/dashboard: Historical chart widgets are no longer displayed on systems without history support.
* frontend/dashboard: Pie chart now displays current values in legend.
* frontend/dashboard: Fixed wrong handle position on some analog widgets.
* startup: Virtual ports are now loaded after peripherals to properly allow port id mappings.

version-0.24.0-beta.1

* core/api: Added support for timestamps in `GET /ports/{id}/history` API call.
* core/expressions: Added support for `HISTORY` function.
* core/expressions: Added support for `AVAILABLE` and `DEFAULT` functions.
* core/expressions: All expression evaluations are now asynchronous.
* core/expressions: Fixed filtering functions.
* core/ports: Value write tasks are now properly rejected when dropped (due to queue full).
* core/vports: Initial value is now `null`, as per new API specs.
* frontend/dashboard: Added chart widgets.
* frontend/dashboard: Various fixes.
* persist: All persistence calls are now asynchronous.
* persist/postgresql: The `asyncpg` library is now used instead of `psycopg2`.
* slaves/devices: Requests are now retried when listening/polling devices before considering them offline.

version-0.23.1

* frontend/devices: Fixed slave device polling update issue.
* frontend/ports/port-history-chart-page: Navigating to future is now prohibited.
* frontend/ports/port-history-chart-page: Added support for specifying custom min/max options for chart.
* slaves: Listening/polling requests are now retried before considering the device offline.

version-0.23.0
What's new (since 0.22.x):
* core: Reorganized some packages to further prevent circular import issues.
* core/api: Added support for history API.
* core/api: Port values are now applied in the background when restoring from backup.
* core/api: Date attribute is now ignored on `PUT /device` (i.e. when restoring from backup).
* core/expressions: Added more date/time-related functions: `MDINTERVAL`, `MILLISECOND`, `DATE`, `BOY`, `BOM`, `BOW`, `BOD`.
* core/expressions: Added optional timestamp argument to date unit functions.
* core/expressions: Added automated tests for all functions.
* core/history: Port historical data is now removed in a background thread to prevent blocking.
* core/main: Updating process is now suspended until core is ready.
* core/main: Updating process is now suspended while restoring from backup.
* core/ports: Id mapping no longer applies to virtual ports.
* frontend: Fixed dashboard refreshing on backup/restore.
* frontend: Added charts support for viewing port historical data.
* frontend: Increased restore procedure timeout to 5 minutes.
* peripherals: Increased default pending tasks queue to 64.
* persist: Various fixes & improvements.
* persist: Fixed various bugs related to custom DB ids.
* persist: Added support for PostgreSQL.
* persist: Added automated tests for all drivers.
* persist/redis: Fixed replace function error when dealing with empty records.
* slaves: Specified timeout is now used when forwarding API calls to slave devices.
* slaves: Fixed `PortNotFound` wrong exception message.
* slaves/api: `PUT /devices` API call now waits for slaves to come online.
* Added automated tests infrastructure.
* Refactored startup/shutdown code.

version-0.23.0-beta.11

* core/main: Updating process is now suspended until core is ready.
* core/main: Updating process is now suspended while restoring from backup.
* frontend: Increased restore procedure timeout to 5 minutes.
* frontend/ports: Fixed small screen navigation buttons layout in history chart page.
* peripherals: Increased default pending tasks queue to 64.
* persist/redis: Fixed `replace` function error when dealing with empty records.
* slaves: Fixed `PortNotFound` wrong exception message.
* slaves/api: `PUT /devices` API call now waits for slaves to come online.

version-0.23.0-beta.10

* history: Port historical data is now removed in a background thread to prevent blocking.
* frontend: Added charts support for viewing port historical data.
* persist: Added support for PostgreSQL.
* persist: Removed support for UnQLite.

version-0.23.0-beta.9