title: Generating Synthetic Input
tags: python windows input


[Example Python Module](combopresser.py) 

From [this stackoverflow](https://stackoverflow.com/questions/13564851/how-to-generate-keyboard-events)
Virtual Key Codes are at: [MSDN](https://learn.microsoft.com/en-gb/windows/win32/inputdev/virtual-key-codes?redirectedfrom=MSDN)
See also [this stackoverflow on unicode](https://stackoverflow.com/questions/77218519/win32-send-unicode-to-application/77221232?noredirect=1#comment136250698_77221232) to see how to send unicode.

Also [this stackoverflow on sending to a specific window](https://stackoverflow.com/questions/2113950/how-to-send-keystrokes-to-a-window)

We use `ctypes` to call to `user32`.
```py
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

# msdn.microsoft.com/en-us/library/dd375731
VK_TAB  = 0x09
VK_MENU = 0x12

# 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))

def AltTab():
    """Press Alt+Tab and hold Alt key for 2 seconds
    in order to see the overlay.
    """
    PressKey(VK_MENU)   # Alt
    PressKey(VK_TAB)    # Tab
    ReleaseKey(VK_TAB)  # Tab~
    time.sleep(2)
    ReleaseKey(VK_MENU) # Alt~

if __name__ == "__main__":
    AltTab()
```

# Unicode
From [this stackoverflow](https://stackoverflow.com/questions/77218519/win32-send-unicode-to-application/77221232?noredirect=1#comment136250698_77221232)
```cpp
#include <vector>
#include <string>

void SendInputString(const std::wstring &str)
{
    int len = str.length();
    if (len == 0) return;

    std::vector<INPUT> in(len*2);
    ZeroMemory(&in[0], in.size()*sizeof(INPUT));

    int i = 0, idx = 0;
    while (i < len)
    {
        WORD ch = (WORD) str[i++];

        if ((ch < 0xD800) || (ch > 0xDFFF))
        {
            in[idx].type = INPUT_KEYBOARD;
            in[idx].ki.wScan = ch;
            in[idx].ki.dwFlags = KEYEVENTF_UNICODE;
            ++idx;

            in[idx] = in[idx-1];
            in[idx].ki.dwFlags |= KEYEVENTF_KEYUP;
            ++idx;
        }
        else
        {
            in[idx].type = INPUT_KEYBOARD;
            in[idx].ki.wScan = ch;
            in[idx].ki.dwFlags = KEYEVENTF_UNICODE;
            ++idx;

            in[idx].type = INPUT_KEYBOARD;
            in[idx].ki.wScan = (WORD) str[i++];
            in[idx].ki.dwFlags = KEYEVENTF_UNICODE;
            ++idx;

            in[idx] = in[idx-2];
            in[idx].ki.dwFlags |= KEYEVENTF_KEYUP;
            ++idx;

            in[idx] = in[idx-2];
            in[idx].ki.dwFlags |= KEYEVENTF_KEYUP;
            ++idx;
        }
    }

    SendInput(in.size(), &in[0], sizeof(INPUT));
}
```

# Sending To A Window
From [this stackoverflow](https://stackoverflow.com/questions/2113950/how-to-send-keystrokes-to-a-window)
```cpp
int SendKeystrokesToNotepad( const TCHAR *const text )
{
    INPUT *keystroke;
    UINT i, character_count, keystrokes_to_send, keystrokes_sent;
    HWND notepad;

    assert( text != NULL );

    //Get the handle of the Notepad window.
    notepad = FindWindow( _T( "Notepad" ), NULL );
    if( notepad == NULL )
        return 0;

    //Bring the Notepad window to the front.
    if( !SetForegroundWindow( notepad ) )
        return 0;

    //Fill in the array of keystrokes to send.
    character_count = _tcslen( text );
    keystrokes_to_send = character_count * 2;
    keystroke = new INPUT[ keystrokes_to_send ];
    for( i = 0; i < character_count; ++i )
    {
        keystroke[ i * 2 ].type = INPUT_KEYBOARD;
        keystroke[ i * 2 ].ki.wVk = 0;
        keystroke[ i * 2 ].ki.wScan = text[ i ];
        keystroke[ i * 2 ].ki.dwFlags = KEYEVENTF_UNICODE;
        keystroke[ i * 2 ].ki.time = 0;
        keystroke[ i * 2 ].ki.dwExtraInfo = GetMessageExtraInfo();

        keystroke[ i * 2 + 1 ].type = INPUT_KEYBOARD;
        keystroke[ i * 2 + 1 ].ki.wVk = 0;
        keystroke[ i * 2 + 1 ].ki.wScan = text[ i ];
        keystroke[ i * 2 + 1 ].ki.dwFlags = KEYEVENTF_UNICODE | KEYEVENTF_KEYUP;
        keystroke[ i * 2 + 1 ].ki.time = 0;
        keystroke[ i * 2 + 1 ].ki.dwExtraInfo = GetMessageExtraInfo();
    }

    //Send the keystrokes.
    keystrokes_sent = SendInput( ( UINT )keystrokes_to_send, keystroke, sizeof( *keystroke ) );
    delete [] keystroke;

    return keystrokes_sent == keystrokes_to_send;
}
```

# Key Codes
From MSDN linked above.
```csv sep=@
VK_LBUTTON@0x01@Left mouse button
VK_RBUTTON@0x02@Right mouse button
VK_CANCEL@0x03@Control-break processing
VK_MBUTTON@0x04@Middle mouse button
VK_XBUTTON1@0x05@X1 mouse button
VK_XBUTTON2@0x06@X2 mouse button
-@0x07@Reserved
VK_BACK@0x08@BACKSPACE key
VK_TAB@0x09@TAB key
-@0x0A-0B@Reserved
VK_CLEAR@0x0C@CLEAR key
VK_RETURN@0x0D@ENTER key
-@0x0E-0F@Unassigned
VK_SHIFT@0x10@SHIFT key
VK_CONTROL@0x11@CTRL key
VK_MENU@0x12@ALT key
VK_PAUSE@0x13@PAUSE key
VK_CAPITAL@0x14@CAPS LOCK key
VK_KANA@0x15@IME Kana mode
VK_HANGUL@0x15@IME Hangul mode
VK_IME_ON@0x16@IME On
VK_JUNJA@0x17@IME Junja mode
VK_FINAL@0x18@IME final mode
VK_HANJA@0x19@IME Hanja mode
VK_KANJI@0x19@IME Kanji mode
VK_IME_OFF@0x1A@IME Off
VK_ESCAPE@0x1B@ESC key
VK_CONVERT@0x1C@IME convert
VK_NONCONVERT@0x1D@IME nonconvert
VK_ACCEPT@0x1E@IME accept
VK_MODECHANGE@0x1F@IME mode change request
VK_SPACE@0x20@SPACEBAR
VK_PRIOR@0x21@PAGE UP key
VK_NEXT@0x22@PAGE DOWN key
VK_END@0x23@END key
VK_HOME@0x24@HOME key
VK_LEFT@0x25@LEFT ARROW key
VK_UP@0x26@UP ARROW key
VK_RIGHT@0x27@RIGHT ARROW key
VK_DOWN@0x28@DOWN ARROW key
VK_SELECT@0x29@SELECT key
VK_PRINT@0x2A@PRINT key
VK_EXECUTE@0x2B@EXECUTE key
VK_SNAPSHOT@0x2C@PRINT SCREEN key
VK_INSERT@0x2D@INS key
VK_DELETE@0x2E@DEL key
VK_HELP@0x2F@HELP key
0x30@0 key
0x31@1 key
0x32@2 key
0x33@3 key
0x34@4 key
0x35@5 key
0x36@6 key
0x37@7 key
0x38@8 key
0x39@9 key
-@0x3A-40@Undefined
0x41@A key
0x42@B key
0x43@C key
0x44@D key
0x45@E key
0x46@F key
0x47@G key
0x48@H key
0x49@I key
0x4A@J key
0x4B@K key
0x4C@L key
0x4D@M key
0x4E@N key
0x4F@O key
0x50@P key
0x51@Q key
0x52@R key
0x53@S key
0x54@T key
0x55@U key
0x56@V key
0x57@W key
0x58@X key
0x59@Y key
0x5A@Z key
VK_LWIN@0x5B@Left Windows key
VK_RWIN@0x5C@Right Windows key
VK_APPS@0x5D@Applications key
-@0x5E@Reserved
VK_SLEEP@0x5F@Computer Sleep key
VK_NUMPAD0@0x60@Numeric keypad 0 key
VK_NUMPAD1@0x61@Numeric keypad 1 key
VK_NUMPAD2@0x62@Numeric keypad 2 key
VK_NUMPAD3@0x63@Numeric keypad 3 key
VK_NUMPAD4@0x64@Numeric keypad 4 key
VK_NUMPAD5@0x65@Numeric keypad 5 key
VK_NUMPAD6@0x66@Numeric keypad 6 key
VK_NUMPAD7@0x67@Numeric keypad 7 key
VK_NUMPAD8@0x68@Numeric keypad 8 key
VK_NUMPAD9@0x69@Numeric keypad 9 key
VK_MULTIPLY@0x6A@Multiply key
VK_ADD@0x6B@Add key
VK_SEPARATOR@0x6C@Separator key
VK_SUBTRACT@0x6D@Subtract key
VK_DECIMAL@0x6E@Decimal key
VK_DIVIDE@0x6F@Divide key
VK_F1@0x70@F1 key
VK_F2@0x71@F2 key
VK_F3@0x72@F3 key
VK_F4@0x73@F4 key
VK_F5@0x74@F5 key
VK_F6@0x75@F6 key
VK_F7@0x76@F7 key
VK_F8@0x77@F8 key
VK_F9@0x78@F9 key
VK_F10@0x79@F10 key
VK_F11@0x7A@F11 key
VK_F12@0x7B@F12 key
VK_F13@0x7C@F13 key
VK_F14@0x7D@F14 key
VK_F15@0x7E@F15 key
VK_F16@0x7F@F16 key
VK_F17@0x80@F17 key
VK_F18@0x81@F18 key
VK_F19@0x82@F19 key
VK_F20@0x83@F20 key
VK_F21@0x84@F21 key
VK_F22@0x85@F22 key
VK_F23@0x86@F23 key
VK_F24@0x87@F24 key
-@0x88-8F@Reserved
VK_NUMLOCK@0x90@NUM LOCK key
VK_SCROLL@0x91@SCROLL LOCK key
-@0x92-96@OEM specific
-@0x97-9F@Unassigned
VK_LSHIFT@0xA0@Left SHIFT key
VK_RSHIFT@0xA1@Right SHIFT key
VK_LCONTROL@0xA2@Left CONTROL key
VK_RCONTROL@0xA3@Right CONTROL key
VK_LMENU@0xA4@Left ALT key
VK_RMENU@0xA5@Right ALT key
VK_BROWSER_BACK@0xA6@Browser Back key
VK_BROWSER_FORWARD@0xA7@Browser Forward key
VK_BROWSER_REFRESH@0xA8@Browser Refresh key
VK_BROWSER_STOP@0xA9@Browser Stop key
VK_BROWSER_SEARCH@0xAA@Browser Search key
VK_BROWSER_FAVORITES@0xAB@Browser Favorites key
VK_BROWSER_HOME@0xAC@Browser Start and Home key
VK_VOLUME_MUTE@0xAD@Volume Mute key
VK_VOLUME_DOWN@0xAE@Volume Down key
VK_VOLUME_UP@0xAF@Volume Up key
VK_MEDIA_NEXT_TRACK@0xB0@Next Track key
VK_MEDIA_PREV_TRACK@0xB1@Previous Track key
VK_MEDIA_STOP@0xB2@Stop Media key
VK_MEDIA_PLAY_PAUSE@0xB3@Play/Pause Media key
VK_LAUNCH_MAIL@0xB4@Start Mail key
VK_LAUNCH_MEDIA_SELECT@0xB5@Select Media key
VK_LAUNCH_APP1@0xB6@Start Application 1 key
VK_LAUNCH_APP2@0xB7@Start Application 2 key
-@0xB8-B9@Reserved
VK_OEM_1@0xBA@Used for miscellaneous characters; it can vary by keyboard. For the US standard keyboard, the ;: key
VK_OEM_PLUS@0xBB@For any country/region, the + key
VK_OEM_COMMA@0xBC@For any country/region, the , key
VK_OEM_MINUS@0xBD@For any country/region, the - key
VK_OEM_PERIOD@0xBE@For any country/region, the . key
VK_OEM_2@0xBF@Used for miscellaneous characters; it can vary by keyboard. For the US standard keyboard, the /? key
VK_OEM_3@0xC0@Used for miscellaneous characters; it can vary by keyboard. For the US standard keyboard, the `~ key
-@0xC1-DA@Reserved
VK_OEM_4@0xDB@Used for miscellaneous characters; it can vary by keyboard. For the US standard keyboard, the [{ key
VK_OEM_5@0xDC@Used for miscellaneous characters; it can vary by keyboard. For the US standard keyboard, the \\| key
VK_OEM_6@0xDD@Used for miscellaneous characters; it can vary by keyboard. For the US standard keyboard, the ]} key
VK_OEM_7@0xDE@Used for miscellaneous characters; it can vary by keyboard. For the US standard keyboard, the '" key
VK_OEM_8@0xDF@Used for miscellaneous characters; it can vary by keyboard.
-@0xE0@Reserved
-@0xE1@OEM specific
VK_OEM_102@0xE2@The <> keys on the US standard keyboard, or the \\| key on the non-US 102-key keyboard
-@0xE3-E4@OEM specific
VK_PROCESSKEY@0xE5@IME PROCESS key
-@0xE6@OEM specific
VK_PACKET@0xE7@Used to pass Unicode characters as if they were keystrokes. The VK_PACKET key is the low word of a 32-bit Virtual Key value used for non-keyboard input methods. For more information, see Remark in KEYBDINPUT, SendInput, WM_KEYDOWN, and WM_KEYUP
-@0xE8@Unassigned
-@0xE9-F5@OEM specific
VK_ATTN@0xF6@Attn key
VK_CRSEL@0xF7@CrSel key
VK_EXSEL@0xF8@ExSel key
VK_EREOF@0xF9@Erase EOF key
VK_PLAY@0xFA@Play key
VK_ZOOM@0xFB@Zoom key
VK_NONAME@0xFC@Reserved
VK_PA1@0xFD@PA1 key
VK_OEM_CLEAR@0xFE@Clear key
```