Python does not find the dwTime attribute of the Structure class

Question

Here my code:

from ctypes import byref, c_uint, c_ulong, sizeof, Structure, windll
import ctypes
import random
import sys
import time
import win32api


class LASTINPUTINFO(Structure):
    """Мы импортировали необходимые модули и создали структуру LASTINPUTINFO
    для хранения временной метки (в миллисекундах), обозначающей момент
обнаружения последнего события ввода в системе. """
fields_ = [
    ('cbSize', ctypes.c_uint),
    ('dwTime', ctypes.c_ulong)
]


def get_last_input():
"""Дальше создаем функцию get_last_input, чтобы, собственно, определить этот момент."""

struct_lastinputinfo = LASTINPUTINFO()

# Обратите
# внимание на то, что прежде чем выполнять вызов, переменную cbSize 
# нужно инициализировать с использованием размера структуры.
struct_lastinputinfo.cbSize = sizeof(LASTINPUTINFO)  # 

# Затем мы
# вызываем функцию GetLastInputInfo, которая присваивает полю struct_
# lastinputinfo.dwTime временную метку.
windll.user32.GetLastInputInfo(byref(struct_lastinputinfo))

# Следующий шаг состоит в определении того,
# как долго проработала система. Для этого применяется вызов
# функции GetTickCount .
run_time = windll.kernel32.GetTickCount()  # 

# Переменная elapsed должна быть равна разности
# между временем работы системы и временем последнего ввода.
elapsed = run_time - struct_lastinputinfo.dwTime
print(f"[*] It's been {elapsed} milliseconds since the last event.")
return elapsed


# Небольшой
# фрагмент кода, размещенный в конце , позволяет выполнить простую проверку
while True:  # 
get_last_input()
time.sleep(1)

But I get this error:

Traceback (most recent call last): File "C:\Users\user\PycharmProjects\sandbox_detected\sandbox_detect.py", line 49, in get_last_input() File "C:\Users\user\PycharmProjects\sandbox_detected\sandbox_detect.py", line 41, in get_last_input elapsed = run_time - struct_lastinputinfo.dwTime AttributeError: 'LASTINPUTINFO' object has no attribute 'dwTime'

Help me please.

UPD:

@MegaEmailman Thank you, the code now does not throw exceptions, but it is not clear why it does not work correctly and displays only this:

[*] It's been 0 milliseconds since the last event.
[*] It's been 0 milliseconds since the last event.
[*] It's been 0 milliseconds since the last event.
[*] It's been 0 milliseconds since the last event.
[*] It's been 0 milliseconds since the last event.
[*] It's been 0 milliseconds since the last event.

CristiFati · Accepted Answer · 2022-07-06T21:37:39.070

There are a bunch of critical errors in your code (besides the wrong indentation - which I consider a formatting issue):

According to [Python.Docs]: ctypes - Structures and unions (emphasis is mine):

Structures and unions must derive from the Structure and Union base classes which are defined in the ctypes module. Each subclass must define a _fields_ attribute. _fields_ must be a list of 2-tuples, containing a field name and a field type.

So, it's _fields_ (surrounded by UnderScores)
Always define argtypes and restype for the functions you call via CTypes. Check [SO]: C function called from Python via ctypes returns incorrect value (@CristiFati's answer) for more details
Not critical, but when working with WinAPI, use the WinTypes module which defines some types (which are practically aliases)

I modified your code with some improvements:

Moved the cbSize member set in the initializer, so it is no longer necessary every time the class gets instantiated
Exit when Esc is pressed

code00.py:

#!/usr/bin/env python

import ctypes as ct
import msvcrt
import sys
import time
from ctypes import wintypes as wt


class LASTINPUTINFO(ct.Structure):
    _fields_ = (
        ("cbSize", wt.UINT),
        ("dwTime", wt.DWORD),
    )

    def __init__(self, dwTime=0):
        super().__init__(ct.sizeof(self.__class__), dwTime)


PLASTINPUTINFO = ct.POINTER(LASTINPUTINFO)


kernel32 = ct.WinDLL("Kernel32")
user32 = ct.WinDLL("User32")

GetTickCount = kernel32.GetTickCount
GetTickCount.argtypes = ()
GetTickCount.restype = wt.DWORD

GetLastInputInfo = user32.GetLastInputInfo
GetLastInputInfo.argtypes = (PLASTINPUTINFO,)
GetLastInputInfo.restype = wt.BOOL


def get_last_input():
    lii = LASTINPUTINFO()
    GetLastInputInfo(ct.byref(lii))
    run_time = GetTickCount()
    print("\nLast input time: {:d}\nTick count: {:d}\nElapsed: {:d}".format(lii.dwTime, run_time, run_time - lii.dwTime))


def main(*argv):
    while True:
        get_last_input()
        time.sleep(1)
        if msvcrt.kbhit():
            if ord(msvcrt.getch()) == 0x1B:
                break


if __name__ == "__main__":
    print("Python {:s} {:03d}bit on {:s}\n".format(" ".join(elem.strip() for elem in sys.version.split("\n")),
                                                   64 if sys.maxsize > 0x100000000 else 32, sys.platform))
    rc = main(*sys.argv[1:])
    print("\nDone.")
    sys.exit(rc)

Output (run the program while moving mouse and pressing keys):

[cfati@CFATI-5510-0:e:\Work\Dev\StackOverflow\q072887838]> "e:\Work\Dev\VEnvs\py_pc064_03.09_test0\Scripts\python.exe" ./code00.py
Python 3.9.9 (tags/v3.9.9:ccb0e6a, Nov 15 2021, 18:08:50) [MSC v.1929 64 bit (AMD64)] 064bit on win32


Last input time: 392676796
Tick count: 392676921
Elapsed: 125

Last input time: 392676921
Tick count: 392677937
Elapsed: 1016

Last input time: 392676921
Tick count: 392678953
Elapsed: 2032

Last input time: 392676921
Tick count: 392679968
Elapsed: 3047

Last input time: 392676921
Tick count: 392680968
Elapsed: 4047

Last input time: 392681421
Tick count: 392681984
Elapsed: 563

Last input time: 392682812
Tick count: 392682984
Elapsed: 172

Last input time: 392683937
Tick count: 392684000
Elapsed: 63

Last input time: 392684078
Tick count: 392685000
Elapsed: 922

Last input time: 392685687
Tick count: 392686015
Elapsed: 328

Last input time: 392686828
Tick count: 392687031
Elapsed: 203

Last input time: 392688046
Tick count: 392688046
Elapsed: 0

Last input time: 392688484
Tick count: 392689062
Elapsed: 578

Done.

Python does not find the dwTime attribute of the Structure class

1 Answers1