How can I translate Linux keycodes from /dev/input/event* to ASCII in Perl?

Question

I\'m writing a Perl script that reads data from the infamous /dev/input/event* and I didn\'t find a way to translate the key codes generated by the kernel into

Answer 1

To read the barcodes from a barcode reader I missed a simple application to get the pure key strokes into a string. That's by far easier to do a complete keyboard translation as the barcodes usually contain mostly numbers and some few normal ascii characters. So, perhaps, this simple python3 script may help as well others to get started. It requires python3-evdev as library. For sure, you may have to adapt the InputDevice. This works for the Manhatten reader.

from evdev import InputDevice, categorize, ecodes

dev = InputDevice('/dev/input/by-id/usb-040b_6543-if01-event-kbd')

print(dev)

shiftPressed = False
ctrlPressed = False
string = ""

for event in dev.read_loop():
    if event.type == ecodes.EV_KEY:
        keyEvent = categorize(event)
        # handle release of special keys
        if keyEvent.keystate == 0:
            if keyEvent.keycode=="KEY_LEFTSHIFT":
                shiftPressed = False
                continue
            if keyEvent.keycode=="KEY_LEFTCTRL":
                ctrlPressed = False
                continue
        # handle key presses
        if keyEvent.keystate == 1:
            if keyEvent.keycode=="KEY_LEFTSHIFT":
                shiftPressed = True
                continue
            if keyEvent.keycode=="KEY_LEFTCTRL":
                ctrlPressed = True
                continue
            if ctrlPressed:
                continue

            key = keyEvent.keycode[4:]

            if key == "ENTER":
                print(string)
                string = ""
                continue

            dict2 = {"Z" : "Y", "Y": "Z"}
            if key in dict2:
                key = dict2[key]

            if not (shiftPressed):
                key = key.lower()
            else:
                dict = {"0" : "=",
                        "1" : "!",
                        "2" : "\"",
                        "3" : "§",
                        "4" : "$",
                        "5" : "%",
                        "6" : "&",
                        "7" : "/",
                        "8" : "(",
                        "9" : ")"}
                if key in dict:
                    key = dict[key]
            string+=key