Python - Unable to create an awaitable class (awaitable instance gets created instead) - python-3.x

Python doc's suggest that one can implement __await__ method that returns and iterator and the class will become awaitable. I tested the following code.
class AwaitableClass:
async def set_attr(self):
self.result = await some_coro()
def __await__(self):
return self.set_attr().__await__()
async def main():
obj = await AwaitableClass() #obj gets bound to None
obj = AwaitableClass() #Creates an instance of AwaitbleClass
await obj #Calls __await__
Any ideas?


You can create async iterators/generators without classes, for example:
async def things():
for i in range(10):
yield i
await asyncio.sleep(1)
async def run():
async for thing in things:
print(thing)
Likewise, to do this in a class, you need to implement __aiter__ function and __anext__ coro functions. Like:
class TestImplementation:
def __init__(self):
self.count = 0
def __aiter__(self):
return self
async def __anext__(self):
self.count += 1
if self.count > 10:
raise StopAsyncIteration
await asyncio.sleep(1)
return self.count
async def run():
async for thing in TestImplementation():
print(thing)

Related

Does anyone have a working example of a GATT HID Keyboard Server using BLUEZ?

I'm using my Raspbery PI4-b with Raspian Lite distro to write a virtual keyboard using BLUEZ to create a GATT HID (HOGP) Service.
I've taken the GATT sample code for a heart rate monitor service provided by BLUEZ and modified it to add Services and Characteristics to try and make my GATT HID Keyboard Server.
I did the best I could to get my server working but can't quite figure it out. So was wondering if anyone has a working example of this type service I could work from?
I have my server connecting ok to Windows 10 and my Android phone as a ble keyboard peripheral, but neither client will start the report characteristic notify function so i can start sending reports containing key press data.
THANKS!!! In advance for any help.
The code I created from the BLUEZ heart monitor sample:
#!/usr/bin/env python3
# SPDX-License-Identifier: LGPL-2.1-or-later
import time
import dbus, dbus.exceptions
import dbus.mainloop.glib
import dbus.service
import array
try:
from gi.repository import GObject
except ImportError:
import gobject as GObject
import sys
from random import randint
mainloop = None
hidService = None
BLUEZ_SERVICE_NAME = 'org.bluez'
GATT_MANAGER_IFACE = 'org.bluez.GattManager1'
DBUS_OM_IFACE = 'org.freedesktop.DBus.ObjectManager'
DBUS_PROP_IFACE = 'org.freedesktop.DBus.Properties'
GATT_SERVICE_IFACE = 'org.bluez.GattService1'
GATT_CHRC_IFACE = 'org.bluez.GattCharacteristic1'
GATT_DESC_IFACE = 'org.bluez.GattDescriptor1'
class InvalidArgsException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.freedesktop.DBus.Error.InvalidArgs'
class NotSupportedException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.NotSupported'
class NotPermittedException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.NotPermitted'
class InvalidValueLengthException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.InvalidValueLength'
class FailedException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.Failed'
class Application(dbus.service.Object):
"""
org.bluez.GattApplication1 interface implementation
"""
def __init__(self, bus):
self.path = '/'
self.services = []
dbus.service.Object.__init__(self, bus, self.path)
self.add_service(HIDService(bus, 0))
self.add_service(DeviceInfoService(bus, 1))
self.add_service(BatteryService(bus, 2))
#self.add_service(TestService(bus, 3))
def get_path(self):
return dbus.ObjectPath(self.path)
def add_service(self, service):
self.services.append(service)
#dbus.service.method(DBUS_OM_IFACE, out_signature='a{oa{sa{sv}}}')
def GetManagedObjects(self):
response = {}
print('GetManagedObjects')
for service in self.services:
response[service.get_path()] = service.get_properties()
chrcs = service.get_characteristics()
for chrc in chrcs:
response[chrc.get_path()] = chrc.get_properties()
descs = chrc.get_descriptors()
for desc in descs:
response[desc.get_path()] = desc.get_properties()
return response
class Service(dbus.service.Object):
"""
org.bluez.GattService1 interface implementation
"""
PATH_BASE = '/org/bluez/example/service'
def __init__(self, bus, index, uuid, primary):
self.path = self.PATH_BASE + str(index)
self.bus = bus
self.uuid = uuid
self.primary = primary
self.characteristics = []
dbus.service.Object.__init__(self, bus, self.path)
def get_properties(self):
return {
GATT_SERVICE_IFACE: {
'UUID': self.uuid,
'Primary': self.primary,
'Characteristics': dbus.Array(
self.get_characteristic_paths(),
signature='o')
}
}
def get_path(self):
return dbus.ObjectPath(self.path)
def add_characteristic(self, characteristic):
self.characteristics.append(characteristic)
def get_characteristic_paths(self):
result = []
for chrc in self.characteristics:
result.append(chrc.get_path())
return result
def get_characteristics(self):
return self.characteristics
#dbus.service.method(DBUS_PROP_IFACE,
in_signature='s',
out_signature='a{sv}')
def GetAll(self, interface):
if interface != GATT_SERVICE_IFACE:
raise InvalidArgsException()
return self.get_properties()[GATT_SERVICE_IFACE]
class Characteristic(dbus.service.Object):
"""
org.bluez.GattCharacteristic1 interface implementation
"""
def __init__(self, bus, index, uuid, flags, service):
self.path = service.path + '/char' + str(index)
self.bus = bus
self.uuid = uuid
self.service = service
self.flags = flags
self.descriptors = []
dbus.service.Object.__init__(self, bus, self.path)
def get_properties(self):
return {
GATT_CHRC_IFACE: {
'Service': self.service.get_path(),
'UUID': self.uuid,
'Flags': self.flags,
'Descriptors': dbus.Array(
self.get_descriptor_paths(),
signature='o')
}
}
def get_path(self):
return dbus.ObjectPath(self.path)
def add_descriptor(self, descriptor):
self.descriptors.append(descriptor)
def get_descriptor_paths(self):
result = []
for desc in self.descriptors:
result.append(desc.get_path())
return result
def get_descriptors(self):
return self.descriptors
#dbus.service.method(DBUS_PROP_IFACE,
in_signature='s',
out_signature='a{sv}')
def GetAll(self, interface):
if interface != GATT_CHRC_IFACE:
raise InvalidArgsException()
return self.get_properties()[GATT_CHRC_IFACE]
#dbus.service.method(GATT_CHRC_IFACE,
in_signature='a{sv}',
out_signature='ay')
def ReadValue(self, options):
print('Default ReadValue called, returning error')
raise NotSupportedException()
#dbus.service.method(GATT_CHRC_IFACE, in_signature='aya{sv}')
def WriteValue(self, value, options):
print('Default WriteValue called, returning error')
raise NotSupportedException()
#dbus.service.method(GATT_CHRC_IFACE)
def StartNotify(self):
print('Default StartNotify called, returning error')
raise NotSupportedException()
#dbus.service.method(GATT_CHRC_IFACE)
def StopNotify(self):
print('Default StopNotify called, returning error')
raise NotSupportedException()
#dbus.service.signal(DBUS_PROP_IFACE,
signature='sa{sv}as')
def PropertiesChanged(self, interface, changed, invalidated):
pass
class Descriptor(dbus.service.Object):
"""
org.bluez.GattDescriptor1 interface implementation
"""
def __init__(self, bus, index, uuid, flags, characteristic):
self.path = characteristic.path + '/desc' + str(index)
self.bus = bus
self.uuid = uuid
self.flags = flags
self.chrc = characteristic
dbus.service.Object.__init__(self, bus, self.path)
def get_properties(self):
return {
GATT_DESC_IFACE: {
'Characteristic': self.chrc.get_path(),
'UUID': self.uuid,
'Flags': self.flags,
}
}
def get_path(self):
return dbus.ObjectPath(self.path)
#dbus.service.method(DBUS_PROP_IFACE,
in_signature='s',
out_signature='a{sv}')
def GetAll(self, interface):
if interface != GATT_DESC_IFACE:
raise InvalidArgsException()
return self.get_properties()[GATT_DESC_IFACE]
#dbus.service.method(GATT_DESC_IFACE,
in_signature='a{sv}',
out_signature='ay')
def ReadValue(self, options):
print ('Default ReadValue called, returning error')
raise NotSupportedException()
#dbus.service.method(GATT_DESC_IFACE, in_signature='aya{sv}')
def WriteValue(self, value, options):
print('Default WriteValue called, returning error')
raise NotSupportedException()
class BatteryService(Service):
"""
Fake Battery service that emulates a draining battery.
"""
SERVICE_UUID = '180f'
def __init__(self, bus, index):
Service.__init__(self, bus, index, self.SERVICE_UUID, True)
self.add_characteristic(BatteryLevelCharacteristic(bus, 0, self))
class BatteryLevelCharacteristic(Characteristic):
"""
Fake Battery Level characteristic. The battery level is drained by 2 points
every 5 seconds.
"""
BATTERY_LVL_UUID = '2a19'
def __init__(self, bus, index, service):
Characteristic.__init__(
self, bus, index,
self.BATTERY_LVL_UUID,
['read', 'notify'],
service)
self.notifying = False
self.battery_lvl = 100
self.timer = GObject.timeout_add(30000, self.drain_battery)
def notify_battery_level(self):
if not self.notifying:
return
self.PropertiesChanged(
GATT_CHRC_IFACE,
{ 'Value': [dbus.Byte(self.battery_lvl)] }, [])
def drain_battery(self):
if not self.notifying:
return True
if self.battery_lvl > 0:
self.battery_lvl -= 2
if self.battery_lvl < 5:
#self.battery_lvl = 0
GObject.source_remove(self.timer)
print('Battery Level drained: ' + repr(self.battery_lvl))
self.notify_battery_level()
return True
def ReadValue(self, options):
print('Battery Level read: ' + repr(self.battery_lvl))
return [dbus.Byte(self.battery_lvl)]
def StartNotify(self):
if self.notifying:
print('Already notifying, nothing to do')
return
self.notifying = True
self.notify_battery_level()
def StopNotify(self):
if not self.notifying:
print('Not notifying, nothing to do')
return
self.notifying = False
#sourceId="org.bluetooth.service.device_information" type="primary" uuid="180A"
class DeviceInfoService(Service):
SERVICE_UUID = '180A'
def __init__(self, bus, index):
Service.__init__(self, bus, index, self.SERVICE_UUID, True)
self.add_characteristic(VendorCharacteristic(bus, 0, self))
self.add_characteristic(ProductCharacteristic(bus, 1, self))
self.add_characteristic(VersionCharacteristic(bus, 2, self))
#name="Manufacturer Name String" sourceId="org.bluetooth.characteristic.manufacturer_name_string" uuid="2A29"
class VendorCharacteristic(Characteristic):
CHARACTERISTIC_UUID = '2A29'
def __init__(self, bus, index, service):
Characteristic.__init__(
self, bus, index,
self.CHARACTERISTIC_UUID,
["read"],
service)
self.value = dbus.Array('HodgeCode'.encode(), signature=dbus.Signature('y'))
print(f'***VendorCharacteristic value***: {self.value}')
def ReadValue(self, options):
print(f'Read VendorCharacteristic: {self.value}')
return self.value
#sourceId="org.bluetooth.characteristic.model_number_string" uuid="2A24"
class ProductCharacteristic(Characteristic):
CHARACTERISTIC_UUID = '2A24'
def __init__(self, bus, index, service):
Characteristic.__init__(
self, bus, index,
self.CHARACTERISTIC_UUID,
["read"],
service)
self.value = dbus.Array('smartRemotes'.encode(), signature=dbus.Signature('y'))
print(f'***ProductCharacteristic value***: {self.value}')
def ReadValue(self, options):
print(f'Read ProductCharacteristic: {self.value}')
return self.value
#sourceId="org.bluetooth.characteristic.software_revision_string" uuid="2A28"
class VersionCharacteristic(Characteristic):
CHARACTERISTIC_UUID = '2A28'
def __init__(self, bus, index, service):
Characteristic.__init__(
self, bus, index,
self.CHARACTERISTIC_UUID,
["read"],
service)
self.value = dbus.Array('version 1.0.0'.encode(), signature=dbus.Signature('y'))
print(f'***VersionCharacteristic value***: {self.value}')
def ReadValue(self, options):
print(f'Read VersionCharacteristic: {self.value}')
return self.value
#name="Human Interface Device" sourceId="org.bluetooth.service.human_interface_device" type="primary" uuid="1812"
class HIDService(Service):
SERVICE_UUID = '1812'
def __init__(self, bus, index, application):
Service.__init__(self, bus, index, self.SERVICE_UUID, True)
self.parent = application
self.protocolMode = ProtocolModeCharacteristic(bus, 0, self)
self.hidInfo = HIDInfoCharacteristic(bus, 1, self)
self.controlPoint = ControlPointCharacteristic(bus, 2, self)
self.report = ReportCharacteristic(bus, 3, self)
self.reportMap = ReportMapCharacteristic(bus, 4, self)
self.add_characteristic(self.protocolMode)
self.add_characteristic(self.hidInfo)
self.add_characteristic(self.controlPoint)
self.add_characteristic(self.report)
self.add_characteristic(self.reportMap)
self.protocolMode.ReadValue({})
#name="Protocol Mode" sourceId="org.bluetooth.characteristic.protocol_mode" uuid="2A4E"
class ProtocolModeCharacteristic(Characteristic):
CHARACTERISTIC_UUID = '2A4E'
def __init__(self, bus, index, service):
Characteristic.__init__(
self, bus, index,
self.CHARACTERISTIC_UUID,
["read", "write-without-response"],
service)
#self.value = dbus.Array([1], signature=dbus.Signature('y'))
self.parent = service
self.value = dbus.Array(bytearray.fromhex('01'), signature=dbus.Signature('y'))
print(f'***ProtocolMode value***: {self.value}')
print('********', service.parent)
def ReadValue(self, options):
print(f'Read ProtocolMode: {self.value}')
return self.value
def WriteValue(self, value, options):
print(f'Write ProtocolMode {value}')
self.value = value
#sourceId="org.bluetooth.characteristic.hid_control_point" uuid="2A4C"
class ControlPointCharacteristic(Characteristic):
CHARACTERISTIC_UUID = '2A4C'
def __init__(self, bus, index, service):
Characteristic.__init__(
self, bus, index,
self.CHARACTERISTIC_UUID,
["write-without-response"],
service)
self.value = dbus.Array(bytearray.fromhex('00'), signature=dbus.Signature('y'))
print(f'***ControlPoint value***: {self.value}')
def WriteValue(self, value, options):
print(f'Write ControlPoint {value}')
self.value = value
#id="hid_information" name="HID Information" sourceId="org.bluetooth.characteristic.hid_information" uuid="2A4A"
class HIDInfoCharacteristic(Characteristic):
CHARACTERISTIC_UUID = '2A4A'
def __init__(self, bus, index, service):
Characteristic.__init__(
self, bus, index,
self.CHARACTERISTIC_UUID,
['read'],
service)
self.value = dbus.Array(bytearray.fromhex('01110002'), signature=dbus.Signature('y'))
print(f'***HIDInformation value***: {self.value}')
def ReadValue(self, options):
print(f'Read HIDInformation: {self.value}')
return self.value
#sourceId="org.bluetooth.characteristic.report_map" uuid="2A4B"
class ReportMapCharacteristic(Characteristic):
CHARACTERISTIC_UUID = '2A4B'
def __init__(self, bus, index, service):
Characteristic.__init__(
self, bus, index,
self.CHARACTERISTIC_UUID,
['read'],
service)
self.parent = service
#self.value = dbus.Array(bytearray.fromhex('05010906a101850175019508050719e029e715002501810295017508810395057501050819012905910295017503910395067508150026ff000507190029ff8100c0050C0901A101850275109501150126ff0719012Aff078100C005010906a101850375019508050719e029e715002501810295017508150026ff000507190029ff8100c0'), signature=dbus.Signature('y'))
self.value = dbus.Array(bytearray.fromhex('05010906a101050719e029e71500250175019508810295017508810195067508150025650507190029658100c0'), signature=dbus.Signature('y'))
print(f'***ReportMap value***: {self.value}')
def ReadValue(self, options):
print(f'Read ReportMap: {self.value}')
return self.value
#id="report" name="Report" sourceId="org.bluetooth.characteristic.report" uuid="2A4D"
class ReportCharacteristic(Characteristic):
CHARACTERISTIC_UUID = '2A4D'
def __init__(self, bus, index, service):
Characteristic.__init__(
self, bus, index,
self.CHARACTERISTIC_UUID,
['read', 'notify'],
service)
#self.add_descriptor(ClientConfigurationDescriptor(bus, 0, self))
self.add_descriptor(ReportReferenceDescriptor(bus, 1, self))
#[ 0xA1, reportNum, 0, 0, 0, 0, 0, 0, 0, 0 ]
#self.value = dbus.Array(bytearray.fromhex('00000000000000000000'), signature=dbus.Signature('y'))
self.value = dbus.Array(bytearray.fromhex('0000000000000000'), signature=dbus.Signature('y'))
print(f'***Report value***: {self.value}')
self.notifying = False
#self.battery_lvl = 100
#GObject.timeout_add(5000, self.drain_battery)
def send(self, value='Hey'):
print(f'***send*** {value}');
self.payload = dbus.Array(bytearray.fromhex('a100004800000000'))
self.PropertiesChanged(GATT_CHRC_IFACE, { 'Value': self.payload }, [])
print(f'***sent***');
def ReadValue(self, options):
print(f'Read Report: {self.value}')
return self.value
def WriteValue(self, value, options):
print(f'Write Report {self.value}')
self.value = value
def StartNotify(self):
print(f'Start Notify')
if self.notifying:
print('Already notifying, nothing to do')
return
self.notifying = True
self.notify_battery_level()
def StopNotify(self):
print(f'Stop Notify')
if not self.notifying:
print('Not notifying, nothing to do')
return
self.notifying = False
#name="Client Characteristic Configuration" sourceId="org.bluetooth.descriptor.gatt.client_characteristic_configuration" uuid="2902"
class ClientConfigurationDescriptor(Descriptor):
DESCRIPTOR_UUID = '2902'
def __init__(self, bus, index, characteristic):
Descriptor.__init__(
self, bus, index,
self.DESCRIPTOR_UUID,
['read', 'write'],
characteristic)
self.value = dbus.Array(bytearray.fromhex('0100'), signature=dbus.Signature('y'))
print(f'***ClientConfiguration***: {self.value}')
def ReadValue(self, options):
print(f'Read ClientConfiguration: {self.value}')
return self.value
def WriteValue(self, value, options):
print(f'Write ClientConfiguration {self.value}')
self.value = value
#type="org.bluetooth.descriptor.report_reference" uuid="2908"
class ReportReferenceDescriptor(Descriptor):
DESCRIPTOR_UUID = '2908'
def __init__(self, bus, index, characteristic):
Descriptor.__init__(
self, bus, index,
self.DESCRIPTOR_UUID,
['read'],
characteristic)
self.value = dbus.Array(bytearray.fromhex('0001'), signature=dbus.Signature('y'))
print(f'***ReportReference***: {self.value}')
def ReadValue(self, options):
print(f'Read ReportReference: {self.value}')
return self.value
#############################
# my sandbox
#############################
class TestService(Service):
"""
Dummy test service that provides characteristics and descriptors that
exercise various API functionality.
"""
SERVICE_UUID = '12345678-1234-5678-1234-56789abcdef0'
def __init__(self, bus, index):
Service.__init__(self, bus, index, self.SERVICE_UUID, True)
self.add_characteristic(TestCharacteristic(bus, 0, self))
class TestCharacteristic(Characteristic):
"""
Dummy test characteristic. Allows writing arbitrary bytes to its value, and
contains "extended properties", as well as a test descriptor.
"""
CHARACTERISTIC_UUID = '12345678-1234-5678-1234-56789abcdef1'
def __init__(self, bus, index, service):
Characteristic.__init__(
self, bus, index,
self.CHARACTERISTIC_UUID,
['read', 'write'],
service)
self.add_descriptor(TestDescriptor(bus, 0, self))
#self.value = []
self.value = dbus.Array(bytearray.fromhex('05010906a101850175019508050719e029e715002501810295017508810395057501050819012905910295017503910395067508150026ff000507190029ff8100c0050C0901A101850275109501150126ff0719012Aff078100C005010906a101850375019508050719e029e715002501810295017508150026ff000507190029ff8100c0'), signature=dbus.Signature('y'))
def ReadValue(self, options):
print('TestCharacteristic Read: ' + repr(self.value))
return self.value
def WriteValue(self, value, options):
print('TestCharacteristic Write: ' + repr(value))
self.value = value
class TestDescriptor(Descriptor):
"""
Dummy test descriptor. Returns a static value.
"""
DESCRIPTOR_UUID = '12345678-1234-5678-1234-56789abcdef2'
def __init__(self, bus, index, characteristic):
Descriptor.__init__(
self, bus, index,
self.DESCRIPTOR_UUID,
['read', 'write'],
characteristic)
self.value = dbus.Array('Test'.encode(), signature=dbus.Signature('y'))
print(f'***TestDescriptor***: {self.value}')
def ReadValue(self, options):
print('TestDescriptor Read')
return self.value
def WriteValue(self, value, options):
print(f'TestDescriptor Write: {value}')
self.value = value
def register_app_cb():
print('GATT application registered')
def register_app_error_cb(error):
print('Failed to register application: ' + str(error))
mainloop.quit()
def find_adapter(bus):
remote_om = dbus.Interface(bus.get_object(BLUEZ_SERVICE_NAME, '/'),
DBUS_OM_IFACE)
objects = remote_om.GetManagedObjects()
for o, props in objects.items():
if GATT_MANAGER_IFACE in props.keys():
return o
return None
def main():
global mainloop
dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
bus = dbus.SystemBus()
adapter = find_adapter(bus)
if not adapter:
print('GattManager1 interface not found')
return
service_manager = dbus.Interface(
bus.get_object(BLUEZ_SERVICE_NAME, adapter),
GATT_MANAGER_IFACE)
app = Application(bus)
mainloop = GObject.MainLoop()
print('Registering GATT application...')
service_manager.RegisterApplication(app.get_path(), {},
reply_handler=register_app_cb,
error_handler=register_app_error_cb)
mainloop.run()
if __name__ == '__main__':
main()

Mock a logger defined in the constructor using pytest

I have this class defined:
class User():
def __init__(self):
self.logger = Logger('user.log')
def get_data(self):
_data = {
'username': 'abc'
}
_payload = json.dumps(_data)
self.logger.info("Loaded payload")
return _payload
The test case written for get_data():
#mock.patch('mymodule.file_user.Logger')
def test_get_data(self,mock_logger):
assert User().get_data() == "'username': 'abc'"
mock_logger.info.assert_called_once_with(
'Loaded payload')
The mocking here fails giving the assertion error "Expected 'info' to be called once. Called 0 times."

Logger is a class, self.logger.info() is an instance method. So you need to get the instance of mock_logger via .return_value.
E.g.
logger.py:
class Logger():
def __init__(self, filepath) -> None:
pass
def info(message):
print(message)
user.py:
import json
from logger import Logger
class User():
def __init__(self):
self.logger = Logger('user.log')
def get_data(self):
_data = {
'username': 'abc'
}
_payload = json.dumps(_data)
self.logger.info("Loaded payload")
return _payload
test_user.py:
import unittest
from unittest import mock
from user import User
class TestUesr(unittest.TestCase):
#mock.patch('user.Logger')
def test_get_data(self, mock_logger):
mock_logger_instance = mock_logger.return_value
user = User()
actual = user.get_data()
self.assertEqual(actual, '{"username": "abc"}')
mock_logger_instance.info.assert_called_once_with('Loaded payload')
if __name__ == '__main__':
unittest.main()
unit test result:
⚡ coverage run /Users/dulin/workspace/github.com/mrdulin/python-codelab/src/stackoverflow/66366372/test_user.py && coverage report -m --include='./src/**'
.
----------------------------------------------------------------------
Ran 1 test in 0.002s
OK
Name Stmts Miss Cover Missing
-----------------------------------------------------------------------
src/stackoverflow/66366372/logger.py 5 2 60% 3, 6
src/stackoverflow/66366372/test_user.py 13 0 100%
src/stackoverflow/66366372/user.py 10 0 100%
-----------------------------------------------------------------------
TOTAL 28 2 93%

inheritance and init pattern with asyncio in python

Searching the web i could not find a lot of answers regarding classes and init-patterns in python for inheritance. I would like to use something like the following pattern. Are there any disadvantages for this pattern? One maybe is that there could be no init method for the child.
import asyncio
class Foo(object):
def __init__(self):
self.something = None
#classmethod
async def create(cls, something):
self = cls()
self.something = something
return self
class FooChild(Foo):
def __init__(self):
#...
super().__init__()
#classmethod
async def create(cls, something):
self = await super().create(something)
#...
return self
async def main():
something = "something"
foo = await FooChild.create(something)
if __name__ == '__main__':
asyncio.run(main())

Function name is not defined in a Python class

I have written a class like below:
class Logger:
#staticmethod
def get_timestamp():
import datetime
return datetime.datetime.utcnow()
def print_log(self,color, write_level, msg):
return color
def log_level_print(self,log_level, write_level, msg):
if log_level == 'ERROR':
return print_log(bcolors.FAIL, write_level, msg)
if log_level == 'WARN':
return print_log(bcolors.WARNING, write_level, msg)
if log_level == 'INFO':
return print_log(bcolors.OKGREEN, write_level, msg)
if log_level == 'DEBUG':
return print_log(bcolors.OKBLUE, write_level, msg)
else:
print(f"{Logger.get_timestamp()} {bcolors.FAIL}: Invalid LOG type{bcolors.ENDC}")
return
Here, I am using this class :
from logger import Logger
demo = Logger()
print(demo.log_level_print('ERROR','ssdsd','sdsdsd'))
I am not able to call this function, I'm getting an error:
NameError: name 'print_log' is not defined

You forgot to add self as the first argument of class' methods and when you use the methods. Corrected code:
class Logger:
#staticmethod
def get_timestamp():
import datetime
return datetime.datetime.utcnow()
def print_log(self, color, write_level, msg):
return color
def log_level_print(self, log_level, write_level, msg):
if log_level == 'ERROR':
return self.print_log(bcolors.FAIL, write_level, msg)
if log_level == 'WARN':
return self.print_log(bcolors.WARNING, write_level, msg)
if log_level == 'INFO':
return self.print_log(bcolors.OKGREEN, write_level, msg)
if log_level == 'DEBUG':
return self.print_log(bcolors.OKBLUE, write_level, msg)
else:
print(f"{Logger.get_timestamp()} {bcolors.FAIL}: Invalid LOG type{bcolors.ENDC}")
return
Look, it's a code I'm running:
demo = Logger()
print(demo.log_level_print('ERROR','ssdsd','sdsdsd'))
and this is a result:

I think you're missing a self.
All (EDIT: non static, nor abstract) class methods should have a parameter which is typically named self, like so:
class Logger():
#staticmethod
def get_timestamp():
...
def print_log(self, color, write_level, msg):
...
def log_level_print(self, log_level, write_level, msg):
...
demo = Logger()
print(demo.log_level_print('ERROR','ssdsd','sdsdsd'))

As mentioned you need to call self and scondly it will still throw error if bcolors is not specified. You need to call bcolors. I am assuming that it is some another dependency which you have not specified.
Here is a sample.
class Logger:
#staticmethod
def get_timestamp(self):
import datetime
return datetime.datetime.utcnow()
def print_log(self, color, write_level, msg):
return color
def log_level_print(self, log_level, write_level, msg):
bcolors = [] # temporary empty list
if log_level == 'ERROR':
return self.print_log(bcolors.FAIL, write_level, msg)
if log_level == 'WARN':
return self.print_log(bcolors.WARNING, write_level, msg)
if log_level == 'INFO':
return self.print_log(bcolors.OKGREEN, write_level, msg)
if log_level == 'DEBUG':
return self.print_log(bcolors.OKBLUE, write_level, msg)
else:
print(f"{Logger.get_timestamp()} {bcolors.FAIL}: Invalid LOG type{bcolors.ENDC}")
return
demo = Logger()
print(demo.log_level_print('ERROR','ssdsd','sdsdsd'))

Access app_context from custom Converter in Quart

Is there a solution to get the app context in a class that inherit werkzeug BaseConverter class?
This is my example running in Flask:
from werkzeug.routing import BaseConverter
class CodeConverter(BaseConverter):
app = None
def to_python(self, value):
# Create an app context to get value from db
# and instantiate a class X as obj
return obj
def to_url(self, obj):
value = obj.code
title = obj.title
return "%s/%s"%(value, title)
def crate_app():
...
app.url_map.converters['code'] = CodeConverter
CodeConverter.app = app
...

Well, this works for me.
from werkzeug.routing import BaseConverter
class CodeConverter(BaseConverter):
app = None
async def get_object(self, app, value):
async with app.app_context():
# and instantiate a class X as obj
return obj
def to_python(self, value):
pool = concurrent.futures.ThreadPoolExecutor()
result = pool.submit(asyncio.run, self.get_object(self.__class__.app, value)).result()
return result
def to_url(self, obj):
value = obj.code
title = obj.title
return "%s/%s"%(value, title)
def crate_app():
...
app.url_map.converters['code'] = CodeConverter
CodeConverter.app = app
...

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