Script to emulate key-presses on Windows via Python.

directkeys.py

# directkeys.py
# http://stackoverflow.com/questions/13564851/generate-keyboard-events
# msdn.microsoft.com/en-us/library/dd375731

import ctypes
from ctypes import wintypes
import time

user32 = ctypes.WinDLL('user32', use_last_error=True)

INPUT_MOUSE    = 0
INPUT_KEYBOARD = 1
INPUT_HARDWARE = 2

KEYEVENTF_EXTENDEDKEY = 0x0001
KEYEVENTF_KEYUP       = 0x0002
KEYEVENTF_UNICODE     = 0x0004
KEYEVENTF_SCANCODE    = 0x0008

MAPVK_VK_TO_VSC = 0

# List of all codes for keys:
# # msdn.microsoft.com/en-us/library/dd375731
UP = 0x26
DOWN = 0x28
A = 0x41

# C struct definitions

wintypes.ULONG_PTR = wintypes.WPARAM

class MOUSEINPUT(ctypes.Structure):
    _fields_ = (("dx",          wintypes.LONG),
                ("dy",          wintypes.LONG),
                ("mouseData",   wintypes.DWORD),
                ("dwFlags",     wintypes.DWORD),
                ("time",        wintypes.DWORD),
                ("dwExtraInfo", wintypes.ULONG_PTR))

class KEYBDINPUT(ctypes.Structure):
    _fields_ = (("wVk",         wintypes.WORD),
                ("wScan",       wintypes.WORD),
                ("dwFlags",     wintypes.DWORD),
                ("time",        wintypes.DWORD),
                ("dwExtraInfo", wintypes.ULONG_PTR))

    def __init__(self, *args, **kwds):
        super(KEYBDINPUT, self).__init__(*args, **kwds)
        # some programs use the scan code even if KEYEVENTF_SCANCODE
        # isn't set in dwFflags, so attempt to map the correct code.
        if not self.dwFlags & KEYEVENTF_UNICODE:
            self.wScan = user32.MapVirtualKeyExW(self.wVk,
                                                 MAPVK_VK_TO_VSC, 0)

class HARDWAREINPUT(ctypes.Structure):
    _fields_ = (("uMsg",    wintypes.DWORD),
                ("wParamL", wintypes.WORD),
                ("wParamH", wintypes.WORD))

class INPUT(ctypes.Structure):
    class _INPUT(ctypes.Union):
        _fields_ = (("ki", KEYBDINPUT),
                    ("mi", MOUSEINPUT),
                    ("hi", HARDWAREINPUT))
    _anonymous_ = ("_input",)
    _fields_ = (("type",   wintypes.DWORD),
                ("_input", _INPUT))

LPINPUT = ctypes.POINTER(INPUT)

def _check_count(result, func, args):
    if result == 0:
        raise ctypes.WinError(ctypes.get_last_error())
    return args

user32.SendInput.errcheck = _check_count
user32.SendInput.argtypes = (wintypes.UINT, # nInputs
                             LPINPUT,       # pInputs
                             ctypes.c_int)  # cbSize

# Functions

def PressKey(hexKeyCode):
    x = INPUT(type=INPUT_KEYBOARD,
              ki=KEYBDINPUT(wVk=hexKeyCode))
    user32.SendInput(1, ctypes.byref(x), ctypes.sizeof(x))

def ReleaseKey(hexKeyCode):
    x = INPUT(type=INPUT_KEYBOARD,
              ki=KEYBDINPUT(wVk=hexKeyCode,
                            dwFlags=KEYEVENTF_KEYUP))
    user32.SendInput(1, ctypes.byref(x), ctypes.sizeof(x))

if __name__ == "__main__":
    PressKey(A)
    time.sleep(0.5)
    ReleaseKey(A)
    print("Pressed")

Thank you for your script that I'm using in a game. But I have one big issue, I have a latency/delay of 4 frames, around 50ms. Is there a way to fix it ?

It's normal. The inputs are sent one after an other. Although the delay shouldn't be that notisablebe for a few inputs, the more you have the bigger the delay betwen the first and last one. If you want to have no delay the only way is using multi threading. But the code will need to be modified.

hey, my pc language is turkish and we got "ı" word in our language. My problem is even though I send ascii codes of "i" or "I" for example 0x49 it types "ı". how can i solve that?

Your problem could come from the code using virtual keys not scan keys. This is an easy fix but the code needs to be tweaked. In the lower part of the code

ki=KEYBDINPUT(wVk=hexKeyCode))

change

wvk

to

wScan