caproto.server.PvpropertyData

class caproto.server.PvpropertyData(*, pvname: str, group: PVGroup, pvspec: PVSpec, doc: str | None = None, record: str | Type[T_RecordFields] | None = None, logger: Logger | None = None, **kwargs)

A top-level class for mixing in with ChannelData subclasses.

Takes in a fully-expanded pvname, PVSpec, and group instance.

Parameters:

pvnamestr

The fully expanded process variable name.

groupPVGroup

The PVGroup instance to which this pvproperty belongs.

pvspecPVSpec

The associated PVSpec instance, containing detailed information about the pvproperty.

docstr, optional

Docstring / documentation information.

recordstr, optional

The record type to report over channel access. This can be queried by way of caproto-get record.RTYP or caproto-get -d 38 --format "{response.metadata.value}" record

**kwargs

Passed to the superclass, along with reported_record_type.

Methods

auth_read(hostname, username, data_type, *)	Get DBR data and native data, converted to a specific type
auth_write(hostname, username, data, ...[, ...])	Data write hook for clients.
calculate_length(value)	Calculate the number of elements given a value
check_access(hostname, username)	This always returns AccessRights.READ|AccessRights.WRITE.
get_field(field)	Get a field by name.
is_compatible_array(value)	Check if the provided value is a compatible array.
post_state_change(state, new_value)	This is called by the server when it exits its StateUpdateContext.
pre_state_change(state, new_value)	This is called by the server when it enters its StateUpdateContext.
preprocess_value(value)	Pre-process values destined for verify_value and write
publish(flags)	Publish data to appropriate queues matching the SubscriptionSpec.
read(data_type)	The top-level read method, with a specific requested data type.
subscribe(queue, sub_spec, sub)	Subscribe a queue for the given subscription specification.
unsubscribe(queue, sub_spec)	Unsubscribe a queue for the given subscription specification.
update_fields(value)	This is a hook to update field instance data.
verify_value(value)	The top-level dbr-facing "write" method.
write(value, *[, flags, verify_value, ...])	Write data from native Python types.
write_from_dbr(data, data_type, metadata, *)	Write data from a provided DBR data type.
write_metadata([publish, units, precision, ...])	Write metadata, optionally publishing information to clients.

Attributes

alarm	The ChannelAlarm associated with this data
data_type
default_value
epics_timestamp	EPICS timestamp as (seconds, nanoseconds) since EPICS epoch.
length	The number of elements (length) of the current value
max_length	The maximum number of elements (length) this channel can hold
severity	Alarm severity
status	Alarm status
timestamp	UNIX timestamp in seconds.
value	Read-only access to value data
field_inst
fields
getter
group
log
name
putter
pvname
pvspec
record_type
scan
shutdown
startup
max_subscription_backlog