""":rfc:`5545` VALARM component."""
from __future__ import annotations
from datetime import date, datetime, timedelta
from typing import TYPE_CHECKING, NamedTuple
from icalendar.attr import (
ATTACHMENTS_TYPE_SETTER,
ATTENDEE_TYPE_SETTER,
CONCEPTS_TYPE_SETTER,
LINKS_TYPE_SETTER,
RELATED_TO_TYPE_SETTER,
_set_attachments,
attachments_property,
attendees_property,
create_single_property,
description_property,
property_del_duration,
property_get_duration,
property_set_duration,
repeat_property,
single_int_property,
single_string_property,
single_utc_property,
summary_property,
uid_property,
)
from icalendar.cal.component import Component
from icalendar.cal.examples import get_example
from icalendar.error import InvalidCalendar
if TYPE_CHECKING:
import uuid
from icalendar.compatibility import Self
from icalendar.prop import vBinary, vUri
[docs]
class Alarm(Component):
"""
A "VALARM" calendar component is a grouping of component
properties that defines an alarm or reminder for an event or a
to-do. For example, it may be used to define a reminder for a
pending event or an overdue to-do.
Example:
The following example creates an alarm which uses an audio file
from an FTP server.
.. code-block:: pycon
>>> from icalendar import Alarm
>>> alarm = Alarm.example()
>>> print(alarm.to_ical().decode())
BEGIN:VALARM
ACTION:AUDIO
ATTACH;FMTTYPE=audio/basic:ftp://example.com/pub/sounds/bell-01.aud
DURATION:PT15M
REPEAT:4
TRIGGER;VALUE=DATE-TIME:19970317T133000Z
END:VALARM
"""
name = "VALARM"
# some properties MAY/MUST/MUST NOT appear depending on ACTION value
required = (
"ACTION",
"TRIGGER",
)
singletons = (
"ACTION",
"DESCRIPTION",
"SUMMARY",
"TRIGGER",
"DURATION",
"REPEAT",
"UID",
"PROXIMITY",
"ACKNOWLEDGED",
)
inclusive = (
(
"DURATION",
"REPEAT",
),
(
"SUMMARY",
"ATTENDEE",
),
)
multiple = ("ATTENDEE", "ATTACH", "RELATED-TO")
REPEAT = single_int_property(
"REPEAT",
0,
"""The number of additional times the alarm is triggered after the initial trigger.
Defaults to ``0``, meaning the alarm fires once. To repeat the alarm,
set both :attr:`REPEAT` and :attr:`DURATION`. The :attr:`DURATION`
sets the gap between repetitions. :attr:`REPEAT` is the count of *additional*
triggers, so a :attr:`REPEAT` of ``2`` produces three alarms in total
(the initial trigger plus two repeats).
Conforming with :rfc:`5545#section-3.8.6.2`, this property can appear
once in an :class:`~icalendar.cal.alarm.Alarm` component and must be
paired with :attr:`DURATION`.
Example:
Build an alarm that fires once and then repeats twice at
five-minute intervals.
.. code-block:: pycon
>>> from datetime import timedelta
>>> from icalendar import Alarm
>>> alarm = Alarm()
>>> alarm.TRIGGER = timedelta(minutes=-15)
>>> alarm.DURATION = timedelta(minutes=5)
>>> alarm.REPEAT = 2
>>> alarm.REPEAT
2
Raises:
TypeError: If the value is not an ``int``. Booleans are rejected, too,
even though ``bool`` subclasses ``int``.
~icalendar.error.InvalidCalendar: If the value is negative.
.. versionchanged:: 7.3.0
Negative values are no longer accepted.
""",
min_value=0,
)
DURATION = property(
property_get_duration,
property_set_duration,
property_del_duration,
"""The delay between repeated triggers of a repeating alarm.
Returns a :class:`datetime.timedelta` or ``None`` when the alarm
has no :attr:`DURATION` set. Setting this attribute accepts a
:class:`~datetime.timedelta`; deleting it removes the property
from the component.
:attr:`DURATION` is meaningful only for repeating alarms and must
be paired with :attr:`REPEAT`. The two together produce
:attr:`REPEAT` additional triggers, each spaced by :attr:`DURATION` after
the initial trigger.
Conforming with :rfc:`5545#section-3.8.2.5`, the :attr:`DURATION` property
can appear once in an :class:`~icalendar.cal.alarm.Alarm` component.
Example:
Pair :attr:`DURATION` with :attr:`REPEAT` to produce three
triggers spaced ten minutes apart.
.. code-block:: pycon
>>> from datetime import timedelta
>>> from icalendar import Alarm
>>> alarm = Alarm()
>>> alarm.TRIGGER = timedelta(minutes=-30)
>>> alarm.DURATION = timedelta(minutes=10)
>>> alarm.REPEAT = 2
>>> alarm.DURATION
datetime.timedelta(seconds=600)
""",
)
ACKNOWLEDGED = single_utc_property(
"ACKNOWLEDGED",
"""This property is the UTC datetime at which this alarm was last sent or acknowledged as defined in :rfc:`9074`.
Setting this property allows calendar clients to
dismiss or suppress an alarm across multiple devices. Once set to a value
greater than or equal to the alarm's computed trigger time, conforming clients
will not refire the alarm.
Returns ``None`` when no acknowledgment has been recorded.
Example:
Mark an alarm as acknowledged. Note that the example uses an arbitrary time
for the purpose of passing doctests. In actual practice, clients should
use the current time in UTC, such as ``datetime.now(UTC)``.
.. code-block:: pycon
>>> from datetime import timezone, datetime
>>> from icalendar import Alarm
>>> UTC = timezone.utc
>>> alarm = Alarm()
>>> alarm.ACKNOWLEDGED = datetime(2024, 1, 15, 10, 0, tzinfo=UTC)
>>> alarm.ACKNOWLEDGED
datetime.datetime(2024, 1, 15, 10, 0, tzinfo=ZoneInfo(key='UTC'))
See also:
:attr:`TRIGGER`, the time at which the alarm fires.
""",
)
TRIGGER = create_single_property(
"TRIGGER",
"dt",
(datetime, timedelta),
timedelta | datetime | None,
"""The time at which this alarm fires, per :rfc:`5545#section-3.8.6.3`.
The value is either a :class:`~datetime.timedelta` (relative trigger) or a
UTC :class:`~datetime.datetime` (absolute trigger).
A negative :class:`~datetime.timedelta` fires *before* the related
component boundary (start or end); a positive one fires *after* it.
Use :attr:`TRIGGER_RELATED` to choose whether the offset is measured from
the start or the end of the parent event or to-do.
An absolute trigger fires at an exact UTC point in time regardless of the
parent component's dates.
Examples:
Set an alarm to fire 15 minutes before the start of an event.
.. code-block:: pycon
>>> from datetime import datetime, timedelta, timezone
>>> from icalendar import Alarm, Event
>>> UTC = timezone.utc
>>> event = Event()
>>> event.start = datetime(2024, 1, 15, 10, 0, tzinfo=UTC)
>>> alarm = Alarm()
>>> alarm.TRIGGER = timedelta(minutes=-15)
>>> event.add_component(alarm)
>>> event.alarms.times[0].trigger
datetime.datetime(2024, 1, 15, 9, 45, tzinfo=datetime.timezone.utc)
Set an absolute trigger to fire at a specific UTC time.
.. code-block:: pycon
>>> absolute_alarm = Alarm()
>>> absolute_alarm.TRIGGER = datetime(2024, 1, 15, 9, 45, tzinfo=UTC)
>>> absolute_alarm.TRIGGER
datetime.datetime(2024, 1, 15, 9, 45, tzinfo=datetime.timezone.utc)
See also:
:attr:`TRIGGER_RELATED`, :attr:`DURATION`, :attr:`REPEAT`
""",
)
@property
def TRIGGER_RELATED(self) -> str:
"""The RELATED parameter of the TRIGGER property.
Values are either "START" (default) or "END".
A value of START will set the alarm to trigger off the
start of the associated event or to-do. A value of END will set
the alarm to trigger off the end of the associated event or to-do.
In this example, we create an alarm that triggers two hours after the
end of its parent component.
>>> from icalendar import Alarm
>>> from datetime import timedelta
>>> alarm = Alarm()
>>> alarm.TRIGGER = timedelta(hours=2)
>>> alarm.TRIGGER_RELATED = "END"
"""
trigger = self.get("TRIGGER")
if trigger is None:
return "START"
return trigger.params.get("RELATED", "START")
@TRIGGER_RELATED.setter
def TRIGGER_RELATED(self, value: str):
"""Set "START" or "END"."""
trigger = self.get("TRIGGER")
if trigger is None:
raise ValueError(
"You must set a TRIGGER before setting the RELATED parameter."
)
trigger.params["RELATED"] = value
[docs]
class Triggers(NamedTuple):
"""The computed times of alarm triggers.
start - triggers relative to the start of the Event or Todo (timedelta)
end - triggers relative to the end of the Event or Todo (timedelta)
absolute - triggers at a datetime in UTC
"""
start: tuple[timedelta]
end: tuple[timedelta]
absolute: tuple[datetime]
@property
def triggers(self):
"""The computed triggers of an Alarm.
This takes the TRIGGER, DURATION and REPEAT properties into account.
Here, we create an alarm that triggers 3 times before the start of the
parent component.
>>> from icalendar import Alarm
>>> from datetime import timedelta
>>> alarm = Alarm()
>>> alarm.TRIGGER = timedelta(hours=-4) # trigger 4 hours before START
>>> alarm.DURATION = timedelta(hours=1) # after 1 hour trigger again
>>> alarm.REPEAT = 2 # trigger 2 more times
>>> alarm.triggers.start == (timedelta(hours=-4), timedelta(hours=-3), timedelta(hours=-2))
True
>>> alarm.triggers.end
()
>>> alarm.triggers.absolute
()
"""
start = []
end = []
absolute = []
trigger = self.TRIGGER
if trigger is not None:
if isinstance(trigger, date):
absolute.append(trigger)
add = absolute
elif self.TRIGGER_RELATED == "START":
start.append(trigger)
add = start
else:
end.append(trigger)
add = end
duration = self.DURATION
if duration is not None:
for _ in range(self.repeat):
add.append(add[-1] + duration)
return self.Triggers(
start=tuple(start), end=tuple(end), absolute=tuple(absolute)
)
repeat = repeat_property
attachments = attachments_property
@attachments.setter
def attachments(self, value: ATTACHMENTS_TYPE_SETTER) -> None:
if value is not None and self.ACTION == "AUDIO":
count = len(value) if isinstance(value, list) else 1
if count > 1:
raise InvalidCalendar(
"An AUDIO alarm must not contain more than one attachment.\n"
f"Alarm has {count} attachments."
)
_set_attachments(self, value)
ACTION = single_string_property(
"ACTION",
"""The action invoked when the alarm triggers.
Typical values defined by :rfc:`5545#section-3.8.6.1` are
``AUDIO``, ``DISPLAY``, and ``EMAIL``. The empty string is
returned when no ``ACTION`` property is present.
""",
)
@ACTION.setter
def ACTION(self, value: str | None) -> None:
if value == "AUDIO" and len(self.attachments) > 1:
raise InvalidCalendar(
"An AUDIO alarm must not contain more than one attachment.\n"
f"Alarm has {len(self.attachments)} attachments."
)
self.pop("ACTION", None)
if value is not None:
self.add("ACTION", value)
uid = single_string_property(
"UID",
uid_property.__doc__,
["X-ALARMUID", "X-EVOLUTION-ALARM-UID"],
)
summary = summary_property
description = description_property
attendees = attendees_property
[docs]
@classmethod
def new(
cls,
/,
action: str | None = None,
attachments: ATTACHMENTS_TYPE_SETTER = None,
attendees: ATTENDEE_TYPE_SETTER = None,
concepts: CONCEPTS_TYPE_SETTER = None,
description: str | None = None,
links: LINKS_TYPE_SETTER = None,
refids: list[str] | str | None = None,
related_to: RELATED_TO_TYPE_SETTER = None,
summary: str | None = None,
uid: str | uuid.UUID | None = None,
) -> Self:
"""Create a new alarm with all required properties.
This creates a new Alarm in accordance with :rfc:`5545`.
Parameters:
action: The :attr:`ACTION` of the alarm. Typical values are
``"AUDIO"``, ``"DISPLAY"``, and ``"EMAIL"``. When you set
``"AUDIO"``, the alarm accepts at most one attachment.
attachments: The :attr:`attachments` of the alarm.
attendees: The :attr:`attendees` of the alarm.
concepts: The :attr:`~icalendar.cal.component.Component.concepts` of the alarm.
description: The :attr:`description` of the alarm.
links: The :attr:`~icalendar.cal.component.Component.links` of the alarm.
refids: :attr:`~icalendar.cal.component.Component.refids` of the alarm.
related_to: :attr:`~icalendar.cal.component.Component.related_to` of the alarm.
summary: The :attr:`summary` of the alarm.
uid: The :attr:`uid` of the alarm.
Returns:
:class:`Alarm`
Raises:
~error.InvalidCalendar: If the content is not valid
according to :rfc:`5545`.
.. warning:: As time progresses, we will be stricter with the validation.
"""
alarm: Self = super().new(
links=links,
related_to=related_to,
refids=refids,
concepts=concepts,
)
if action is not None:
alarm.ACTION = action
alarm.attachments = attachments
alarm.summary = summary
alarm.description = description
alarm.uid = uid
alarm.attendees = attendees
return alarm
def _apply_duration_repeat(
self,
duration: timedelta | None,
repeat: int | None,
) -> None:
if duration is not None or repeat is not None:
if duration is None or repeat is None:
raise InvalidCalendar(
"DURATION and REPEAT must be set together or not at all"
)
self.DURATION = duration
self.repeat = repeat
[docs]
@classmethod
def new_display(
cls,
description: str,
trigger: timedelta | datetime,
duration: timedelta | None = None,
repeat: int | None = None,
uid: str | uuid.UUID | None = None,
links: LINKS_TYPE_SETTER = None,
related_to: RELATED_TO_TYPE_SETTER = None,
refids: list[str] | str | None = None,
concepts: CONCEPTS_TYPE_SETTER = None,
) -> Alarm:
"""Create a new DISPLAY alarm that shows a text reminder.
A DISPLAY alarm pops up a text notification at the trigger time.
This is the most common alarm type used by calendar clients.
Conforms to :rfc:`5545#section-3.6.6`.
Parameters:
description: Required. The text to display when the alarm fires.
Corresponds to the :attr:`description` property.
trigger: Required. When the alarm fires, as a :class:`~datetime.timedelta`
relative to the event start (negative means before) or as an
absolute :class:`~datetime.datetime` (recommend UTC-aware).
concepts: The :attr:`~icalendar.cal.component.Component.concepts` of the alarm.
duration: Gap between repeated triggers. Must be paired with
``repeat``. Corresponds to the :attr:`DURATION` property.
links: The :attr:`~icalendar.cal.component.Component.links` of the alarm.
refids: The :attr:`~icalendar.cal.component.Component.refids` of the alarm.
related_to: The :attr:`~icalendar.cal.component.Component.related_to` of the alarm.
repeat: Number of *additional* times to fire after the initial
trigger. Must be paired with ``duration``.
Corresponds to the :attr:`REPEAT` property.
uid: Unique identifier for the alarm or ``None``.
Returns:
:class:`Alarm` with ``ACTION:DISPLAY`` set.
Raises:
~icalendar.error.InvalidCalendar: If required fields are missing
or ``duration`` and ``repeat`` are not both provided together.
Example:
Create a display alarm that fires 15 minutes before the event:
.. code-block:: pycon
>>> from datetime import timedelta
>>> from icalendar import Alarm
>>> alarm = Alarm.new_display(
... description="Team meeting in 15 minutes",
... trigger=timedelta(minutes=-15),
... )
>>> print(alarm.to_ical().decode())
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:Team meeting in 15 minutes
TRIGGER:-PT15M
END:VALARM
Attach the alarm to an event:
.. code-block:: python
from datetime import datetime, timedelta, timezone
from icalendar import Alarm, Event
event = Event.new(
summary="Team meeting",
start=datetime(2025, 6, 1, 10, 0, tzinfo=timezone.utc),
end=datetime(2025, 6, 1, 11, 0, tzinfo=timezone.utc),
)
event.add_component(Alarm.new_display(
description="Team meeting in 15 minutes",
trigger=timedelta(minutes=-15),
))
"""
if not description:
raise InvalidCalendar("DISPLAY alarm requires a description")
if trigger is None:
raise InvalidCalendar("DISPLAY alarm requires a trigger")
alarm: Alarm = cls.new(
action="DISPLAY",
description=description,
uid=uid,
links=links,
related_to=related_to,
refids=refids,
concepts=concepts,
)
alarm.TRIGGER = trigger
alarm._apply_duration_repeat(duration, repeat)
return alarm
[docs]
@classmethod
def new_audio(
cls,
trigger: timedelta | datetime,
attachments: str | bytes | vUri | vBinary | None = None,
duration: timedelta | None = None,
repeat: int | None = None,
uid: str | uuid.UUID | None = None,
links: LINKS_TYPE_SETTER = None,
related_to: RELATED_TO_TYPE_SETTER = None,
refids: list[str] | str | None = None,
concepts: CONCEPTS_TYPE_SETTER = None,
) -> Alarm:
"""Create a new AUDIO alarm that plays a sound.
An AUDIO alarm plays a sound at the trigger time. An optional
``attachments`` URI points to the audio file to play; when omitted,
the client uses its default alert sound.
Conforms to :rfc:`5545#section-3.6.6`.
Parameters:
trigger: Required. When the alarm fires, as a :class:`~datetime.timedelta`
relative to the event start (negative means before) or as an
absolute :class:`~datetime.datetime` (recommend UTC-aware).
attachments: Optional audio attachment. Accepts a URI as a
:class:`str` or :class:`~icalendar.prop.uri.vUri`, or
inline binary audio as :class:`bytes` or
:class:`~icalendar.prop.binary.vBinary`. When ``None``,
the client uses its default sound.
duration: Gap between repeated triggers. Must be paired with
``repeat``. Corresponds to the :attr:`DURATION` property.
links: The :attr:`~icalendar.cal.component.Component.links` of the alarm.
refids: The :attr:`~icalendar.cal.component.Component.refids` of the alarm.
related_to: The :attr:`~icalendar.cal.component.Component.related_to` of the alarm.
repeat: Number of *additional* times to fire after the initial
trigger. Must be paired with ``duration``.
Corresponds to the :attr:`REPEAT` property.
uid: Unique identifier for the alarm or ``None``.
Returns:
:class:`Alarm` with ``ACTION:AUDIO`` set.
Raises:
~icalendar.error.InvalidCalendar: If required fields are missing
or ``duration`` and ``repeat`` are not both provided together.
Example:
Create an audio alarm using a custom sound file:
.. code-block:: pycon
>>> from datetime import timedelta
>>> from icalendar import Alarm
>>> alarm = Alarm.new_audio(
... trigger=timedelta(minutes=-5),
... attachments="ftp://example.com/pub/sounds/bell-01.aud",
... )
>>> print(alarm.to_ical().decode())
BEGIN:VALARM
ACTION:AUDIO
ATTACH:ftp://example.com/pub/sounds/bell-01.aud
TRIGGER:-PT5M
END:VALARM
"""
if trigger is None:
raise InvalidCalendar("AUDIO alarm requires a trigger")
alarm: Alarm = cls.new(
action="AUDIO",
attachments=attachments,
uid=uid,
links=links,
related_to=related_to,
refids=refids,
concepts=concepts,
)
alarm.TRIGGER = trigger
alarm._apply_duration_repeat(duration, repeat)
return alarm
[docs]
@classmethod
def new_email(
cls,
summary: str,
description: str,
trigger: timedelta | datetime,
attendees: ATTENDEE_TYPE_SETTER,
attachments: ATTACHMENTS_TYPE_SETTER = None,
duration: timedelta | None = None,
repeat: int | None = None,
uid: str | uuid.UUID | None = None,
links: LINKS_TYPE_SETTER = None,
related_to: RELATED_TO_TYPE_SETTER = None,
refids: list[str] | str | None = None,
concepts: CONCEPTS_TYPE_SETTER = None,
) -> Alarm:
"""Create a new EMAIL alarm that sends an email notification.
An EMAIL alarm sends an email to each address in ``attendees`` when
the alarm fires.
Conforms to :rfc:`5545#section-3.6.6`.
Parameters:
attendees: Required. One or more recipient addresses as email strings or
:class:`~icalendar.prop.cal_address.vCalAddress` instances. A
single address or a sequence of addresses. At least one is
required.
description: Required. Body of the email.
Corresponds to the :attr:`description` property.
summary: Required. Subject line of the email.
Corresponds to the :attr:`summary` property.
trigger: Required. When the alarm fires, as a :class:`~datetime.timedelta`
relative to the event start (negative means before) or as an
absolute :class:`~datetime.datetime` (recommend UTC-aware).
attachments: The :attr:`attachments` of the alarm. A single value
or a sequence of them. Both URIs and binary data are accepted.
concepts: The :attr:`~icalendar.cal.component.Component.concepts` of the alarm.
duration: Gap between repeated triggers. Must be paired with
``repeat``. Corresponds to the :attr:`DURATION` property.
links: The :attr:`~icalendar.cal.component.Component.links` of the alarm.
refids: The :attr:`~icalendar.cal.component.Component.refids` of the alarm.
related_to: The :attr:`~icalendar.cal.component.Component.related_to` of the alarm.
repeat: Number of *additional* times to fire after the initial
trigger. Must be paired with ``duration``.
Corresponds to the :attr:`REPEAT` property.
uid: Unique identifier for the alarm or ``None``.
Returns:
:class:`Alarm` with ``ACTION:EMAIL`` set.
Raises:
~icalendar.error.InvalidCalendar: If required fields are missing,
``attendees`` is empty, or ``duration`` and ``repeat`` are not
both provided together.
Example:
Create an email alarm sent to two recipients. Plain email strings
and ``mailto:``-prefixed strings are both accepted and normalized
to :class:`~icalendar.prop.cal_address.vCalAddress`:
.. code-block:: pycon
>>> from datetime import timedelta
>>> from icalendar import Alarm
>>> alarm = Alarm.new_email(
... summary="Meeting reminder",
... description="Your meeting starts in 30 minutes.",
... trigger=timedelta(minutes=-30),
... attendees=["user@example.com", "mailto:boss@example.com"],
... )
>>> print(alarm.to_ical().decode())
BEGIN:VALARM
ACTION:EMAIL
ATTENDEE:mailto:user@example.com
ATTENDEE:mailto:boss@example.com
DESCRIPTION:Your meeting starts in 30 minutes.
SUMMARY:Meeting reminder
TRIGGER:-PT30M
END:VALARM
"""
if isinstance(attendees, str):
attendees = [attendees]
if not summary:
raise InvalidCalendar("EMAIL alarm requires a summary")
if not description:
raise InvalidCalendar("EMAIL alarm requires a description")
if trigger is None:
raise InvalidCalendar("EMAIL alarm requires a trigger")
if not attendees:
raise InvalidCalendar("EMAIL alarm requires at least one attendee")
alarm: Alarm = cls.new(
action="EMAIL",
attachments=attachments,
summary=summary,
description=description,
uid=uid,
attendees=attendees,
links=links,
related_to=related_to,
refids=refids,
concepts=concepts,
)
alarm.TRIGGER = trigger
alarm._apply_duration_repeat(duration, repeat)
return alarm
[docs]
@classmethod
def example(cls, name: str = "example") -> Alarm:
"""Return the alarm example with the given name."""
return cls.from_ical(get_example("alarms", name))
__all__ = ["Alarm"]