Sending Messages to Game Windows Through DirectInput and Win32API

message_sender.py

import os
import ctypes
import win32api

w = WindowMgr()
PUL = ctypes.POINTER(ctypes.c_ulong)

class KeyBdInput(ctypes.Structure):
   _fields_ = [("wVk", ctypes.c_ushort),
               ("wScan", ctypes.c_ushort),
               ("dwFlags", ctypes.c_ulong),
               ("time", ctypes.c_ulong),
               ("dwExtraInfo", PUL)]


class HardwareInput(ctypes.Structure):
   _fields_ = [("uMsg", ctypes.c_ulong),
               ("wParamL", ctypes.c_short),
               ("wParamH", ctypes.c_ushort)]


class MouseInput(ctypes.Structure):
   _fields_ = [("dx", ctypes.c_long),
               ("dy", ctypes.c_long),
               ("mouseData", ctypes.c_ulong),
               ("dwFlags", ctypes.c_ulong),
               ("time", ctypes.c_ulong),
               ("dwExtraInfo", PUL)]


class Input_I(ctypes.Union):
   _fields_ = [("ki", KeyBdInput),
               ("mi", MouseInput),
               ("hi", HardwareInput)]


class Input(ctypes.Structure):
   _fields_ = [("type", ctypes.c_ulong),
("ii", Input_I)]

def press_key(key):
   extra = ctypes.c_ulong(0)
   ii_ = Input_I()

   flags = 0x0008

   ii_.ki = KeyBdInput(0, key, flags, 0, ctypes.pointer(extra))
   x = Input(ctypes.c_ulong(1), ii_)
   ctypes.windll.user32.SendInput(1, ctypes.pointer(x), ctypes.sizeof(x))

def release_key(key):
   extra = ctypes.c_ulong(0)
   ii_ = Input_I()

   flags = 0x0008 | 0x0002

   ii_.ki = KeyBdInput(0, key, flags, 0, ctypes.pointer(extra))
   x = Input(ctypes.c_ulong(1), ii_)
   ctypes.windll.user32.SendInput(1, ctypes.pointer(x), ctypes.sizeof(x))
  
def get_game_window():
   w.find_window_wildcard("Minecraft 1*")    # Game window is named 'Minecraft 1.13.1' for example.
   w.set_foreground()
  
# Character map
char_map = {
    'q': 0x10, 'w': 0x11, 'e': 0x12, 'r': 0x13, 't': 0x14, 'z': 0x15, 'u': 0x16, 'i': 0x17, 'o': 0x18, 'p':0x19,
    'a': 0x1E, 's': 0x1F, 'd': 0x20, 'f': 0x21, 'g': 0x22, 'h': 0x23, 'j': 0x24, 'k': 0x25, 'l': 0x26,
    'y': 0x2C, 'x': 0x2D, 'c': 0x2E, 'v': 0x2F, 'b': 0x30, 'n': 0x31, 'm': 0x32 }

# Sending the message using the character map
get_game_window()
press_key(char_map['t'])    # t - opens chat
release_key(char_map['t'])

press_key(char_map['h']);release_key(char_map['h']); # h
press_key(char_map['e']);release_key(char_map['e']); # e
press_key(char_map['l']);release_key(char_map['l']); # l
press_key(char_map['l']);release_key(char_map['l']); # l
press_key(char_map['o']);release_key(char_map['o']); # o

press_key(0x1C);release_key(0x1C); # Submit it (0x1C is ENTER key -> possible char_map extension? ;))

window_helper.py

import win32gui
import re

class WindowMgr:
    """Encapsulates some calls to the winapi for window management"""

    def __init__ (self):
        """Constructor"""
        self._handle = None

    def find_window(self, class_name, window_name=None):
        """find a window by its class_name"""
        self._handle = win32gui.FindWindow(class_name, window_name)

    def _window_enum_callback(self, hwnd, wildcard):
        """Pass to win32gui.EnumWindows() to check all the opened windows"""
        if re.match(wildcard, str(win32gui.GetWindowText(hwnd))) is not None:
            self._handle = hwnd

    def find_window_wildcard(self, wildcard):
        """find a window whose title matches the wildcard regex"""
        self._handle = None
        win32gui.EnumWindows(self._window_enum_callback, wildcard)

    def set_foreground(self):
        """put the window in the foreground"""
        win32gui.SetForegroundWindow(self._handle)

    def get_hwnd(self):
        """returns hwnd for further use"""
        return self._handle

Thank you for the quick response, i really appreciate it.
splitgate and 0.A.D, but that just for testing.

I am building something like a splitkeyboard / joystick-controller for pc. The brain of the project is an arduino pro micro. I am using it in combination with firmata and python.

I decided to use python because i wanna have more than on setup / layout, for each programm it's own layout.
For example I would like to have a layout for blender, inkscape or for gaming, but one layout for each game or program.

could you give me more advices how to get it to work?