How to prevent read_event and input detecting the keypress in python - Stack Overflow

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I have created this function to take user input but only after the user has began to type, while ensuring the input prompt is always first.

Code:

def handle_input(conn):
    try:
        while running:
            # Wait for keypress
            trigger = keyboard.read_event()
            if trigger.event_type == keyboard.KEY_DOWN and len(str(trigger.name)) == 1:
                # Display prompt with initial letter
                sys.stdout.write(f"\r<User> {trigger.name}")
                sys.stdout.flush()
                with output_lock:
                    # Take and process user input
                    user_input = input().strip()
                    process_message(conn, f"{trigger.name}{user_input}")
    except UnicodeDecodeError:
        pass

However I have encountered an issue which randomly occurs. the first keypress will be registered by both keyboard.read_event() and input() in some cases. I am aware it is possible to just backspace the duplicate if it occurs but is there a more premiant fix that could be added preventing this behaviour?

I have created this function to take user input but only after the user has began to type, while ensuring the input prompt is always first.

Code:

def handle_input(conn):
    try:
        while running:
            # Wait for keypress
            trigger = keyboard.read_event()
            if trigger.event_type == keyboard.KEY_DOWN and len(str(trigger.name)) == 1:
                # Display prompt with initial letter
                sys.stdout.write(f"\r<User> {trigger.name}")
                sys.stdout.flush()
                with output_lock:
                    # Take and process user input
                    user_input = input().strip()
                    process_message(conn, f"{trigger.name}{user_input}")
    except UnicodeDecodeError:
        pass

However I have encountered an issue which randomly occurs. the first keypress will be registered by both keyboard.read_event() and input() in some cases. I am aware it is possible to just backspace the duplicate if it occurs but is there a more premiant fix that could be added preventing this behaviour?

• python
• input
• keyboard-events

Share Improve this question Follow asked Nov 22, 2024 at 21:28 AndrewAndrew 2333 bronze badges

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2 Answers 2

Sorted by: Reset to default 1

After looking into it further I found the following Reddit post which encounters a similar issue and uses keyboard.read_event(suppress=True). This prevents the event from being propagated further to the input().

Both keyboard.read_event() and input() capture the same keypress, leading to the first key being duplicated. This happens because keyboard.read_event() does not prevent the keypress from being propagated to the input buffer, which input() then reads.

To address this, you can temporarily suppress keyboard input after detecting the first keypress using keyboard.block_key(trigger.name) and then unblock it when you need to.

Hope this helps you

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