velib_python/dbusitem.py at master · fabiodepascale/velib_python · GitHub

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## IMPORTANT NOTE - MVA 2015-2-5

# This file is deprecated. Use the classes in vedbus.py from now on. If you are

# working on some project, please change it, and make it work with the classes

# in vedbus.py

import dbus

# Python imports

from dbus import String

from lxml.etree import XML

# Local imports

import tracing

## Implements a velib dbus item as a local object.

class Dbusitem(object):

## The constructor introspects the dbus-service.

# And constructs the tree of dbus-object-paths with their dbus-object.

# @param bus the bus-object (SESSION or SYSTEM).

# @param service th dbus-service-name.

# @param path initially the path is \ (root).

def __init__(self, bus, service, path):

#tracing.log.debug('Dbusitem __init__ %s %s %s' % (self, service, path))

self._children = {}

self._dbus_name = service

self._value = None

self._text = None

self._valid = None

self._eventCallback = None

self._object = bus.get_object(service, path)

self._add_children(bus, service)

self._match = None

def __del__(self):

tracing.log.debug('Dbusitem __del__ %s %s' % (self, self.object.object_path))

## Introspects and adds the next dbus-item as a child.

# This class-method instantiates a Dbusitem-object for all node(s).

# @param bus the bus-object

# @param service the dbus-service-name.

def _add_children(self, bus, service):

'''Add the child nodes found by introspection'''

self._children= {};

xml = self._object.Introspect()

data = XML(xml)

# add all child nodes

for child in data.findall('node'):

name = child.get('name')

if name == "/":

continue

child_path = self.object.object_path

# root is reported as /, don't make it //

if child_path != "/":

child_path += "/"

child_path += name

self._children[name] = Dbusitem(bus, service, child_path)

def _add_to_prop_changed(self):

if self._match is None:

self._value = None

self._text = None

self._valid = None

self._match = self.object.connect_to_signal("PropertiesChanged", self._properties_changed_handler)

def _delete(self):

for name in self._children:

self._children[name]._delete()

tracing.log.debug('Dbusitem _delete %s %s' % (self, self.object.object_path))

self._children = None

if self._match:

self._match.remove()

del(self._match)

@property

def object(self):

return self._object

@classmethod

def traceit(cls, item, ctx):

print(item.object.object_path + "=" + item.text)

## Dump the tree to console

def trace(self):

self.foreach(self.traceit)

## Invoke callback for the item and its children

# @param callback the callback-function.

def foreach(self, callback):

callback(self)

for name in self._children:

self._children[name].foreach(callback)

## Allow child nodes be accessed as properties.

def __getattr__(self, key):

return self._children[key]

def AddSetting(self, group, name, defaultValue, itemType, minimum, maximum):

tracing.log.info('%s AddSetting %s %s %s %s %s %s' % (self.object.object_path, group, name, defaultValue, itemType, minimum, maximum))

self.object.AddSetting(group, name, defaultValue, itemType, minimum, maximum)

## Returns the value of the dbus-item.

def GetValue(self):

if self._value is None or self._match is None:

try:

self._value = self.object.GetValue()

except Exception, ex:

tracing.log.error("GetValue %s %s exception %s" % (self._dbus_name, self.object.object_path, ex))

#tracing.log.debug('value %s %s type %s' % (self.object.object_path, str(self._value), type(self._value)))

return self._value

def SetValue(self, value):

# mmm, always use a string for now

variant = String(str(value), variant_level=1)

self.object.SetValue(variant)

value = property(GetValue, SetValue)

def Valid(self):

value = self.GetValue()

self._valid = value != dbus.Array([])

return self._valid

valid = property(Valid)

## Sets the callback for the trigger-event.

# @param eventCallback the event-callback-funciton.

def SetEventCallback(self, eventCallback):

self._eventCallback = eventCallback

@property

def text(self):

if self._text is None or self._match is None:

try:

self._text = self.object.GetText()

except Exception, ex:

tracing.log.error("GetText %s %s exception %s" % (self._dbus_name, self.object.object_path, ex))

return self._text

## Is called the value of a dbus-item changes.

# When the event-callback is set it calls this function.

# @param changes the changed properties.

def _properties_changed_handler(self, changes):

for prop in changes:

if prop == "Value":

self._value = changes[prop]

elif prop == "Text":

self._text = changes[prop]

elif prop == "Valid":

self._valid = changes[prop]

if self._eventCallback:

self._eventCallback(self._dbus_name, self.object.object_path, changes)

#tracing.log.debug("%s %s changed to %s" % (self.object.bus_name, self.object.object_path, changes))

velib_python/dbusitem.py at master · fabiodepascale/velib_python · GitHub

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