platypush/platypush/plugins/dbus.py
2020-08-16 01:57:30 +02:00

130 lines
4.2 KiB
Python

import enum
import json
from typing import Set, Dict, Optional
from xml.etree import ElementTree
import dbus
from platypush.plugins import Plugin, action
class BusType(enum.Enum):
SYSTEM = 'system'
SESSION = 'session'
class DbusPlugin(Plugin):
"""
Plugin to interact with DBus.
Requires:
* **dbus-python** (``pip install dbus-python``)
"""
def __init__(self, **kwargs):
super().__init__(**kwargs)
@staticmethod
def _get_bus_names(bus: dbus.Bus) -> Set[str]:
return set([str(name) for name in bus.list_names() if not name.startswith(':')])
@classmethod
def path_names(cls, bus: dbus.Bus, service: str, object_path='/', paths=None, service_dict=None):
if not paths:
paths = {}
paths[object_path] = {}
obj = bus.get_object(service, object_path)
interface = dbus.Interface(obj, 'org.freedesktop.DBus.Introspectable')
xml_string = interface.Introspect()
root = ElementTree.fromstring(xml_string)
for child in root:
if child.tag == 'node':
if object_path == '/':
object_path = ''
new_path = '/'.join((object_path, child.attrib['name']))
cls.path_names(bus, service, new_path, paths)
else:
if not object_path:
object_path = '/'
function_dict = {}
for func in list(child):
if func.tag not in function_dict.keys():
function_dict[func.tag] = []
function_dict[func.tag].append(func.attrib['name'])
if function_dict:
paths[object_path][child.attrib['name']] = function_dict
if not service_dict:
service_dict = {}
if paths:
service_dict[service] = paths
return service_dict
@action
def query(self, service: Optional[str] = None, system_bus: bool = True, session_bus: bool = True) \
-> Dict[str, dict]:
"""
Query DBus for a specific service or for the full list of services.
:param service: Service name (default: None, query all services).
:param system_bus: Query the system bus (default: True).
:param session_bus: Query the session bus (default: True).
:return: A ``{service_name -> {properties}}`` mapping.
"""
busses = {}
response = {}
if system_bus:
busses['system'] = dbus.SystemBus()
if session_bus:
busses['session'] = dbus.SessionBus()
for bus_name, bus in busses.items():
services = {}
service_names = self._get_bus_names(bus)
if not service:
for srv in service_names:
services[srv] = self.path_names(bus, srv)
elif service in service_names:
services[service] = self.path_names(bus, service)
response[bus_name] = services
return response
@action
def execute(self, service: str, path: str, method_name: str, args: Optional[list] = None,
interface: Optional[str] = None, bus_type: str = BusType.SESSION.value):
"""
Execute a method exposed on DBus.
:param service: Service/bus name (e.g. ``org.platypush.Bus``).
:param path: Object path (e.g. ``/MessageService``).
:param method_name: Method name (e.g. ``Post``).
:param args: Arguments to be passed to the method, depending on the method signature.
:param interface: Interface name (e.g. ``org.platypush.MessageBusInterface``).
:param bus_type: Bus type (supported: ``system`` and ``session`` - default: ``session``).
:return: Return value of the executed method.
"""
if not args:
args = []
kwargs = {}
if interface:
kwargs['dbus_interface'] = interface
bus_type = BusType(bus_type)
bus = dbus.SessionBus() if bus_type == BusType.SESSION else dbus.SystemBus()
obj = bus.get_object(bus_name=service, object_path=path)
ret = getattr(obj, method_name)(*args, **kwargs)
return json.loads(json.dumps(ret))
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