Develop Reference

Python Block Keyboard / Mouse Input

i am currently trying to write a short script that will rickroll (open a youtube link) while the user is watching and can't interfere.
I have managed to open insert the link slowly letter by letter and am now trying to block user inputs.
I have tried using the ctypes import to block all inputs, run the script and then unblock again, but it somehow won't block the input. I'm just receiving my RuntimeError message.
How do i fix it, so the inputs get blocked?
Thanks in advance!
Heres the code:
import subprocess
import pyautogui
import time
import ctypes
from ctypes import wintypes
BlockInput = ctypes.windll.user32.BlockInput
BlockInput.argtypes = [wintypes.BOOL]
BlockInput.restype = wintypes.BOOL
blocked = BlockInput(True)
if blocked:
try:
subprocess.Popen(["C:\\Program Files\\Google\\Chrome\\Application\\chrome.exe",])
time.sleep(3)
pyautogui.write('www.youtube.com/watch?v=DLzxrzFCyOs', interval= 0.5)
pyautogui.hotkey('enter')
finally:
unblocked = BlockInput(False)
else:
raise RuntimeError('Input is already blocked by another thread')

You can use the keyboard module to block all keyboard inputs and the mouse module to constantly move the mouse, preventing the user from moving it.
See these links for more details:
https://github.com/boppreh/keyboard
https://github.com/boppreh/mouse
This blocks all the keys on the keyboard (the 150 is large enough to ensure all keys are blocked).
#### Blocking Keyboard ####
import keyboard
#blocks all keys of keyboard
for i in range(150):
keyboard.block_key(i)
This effectively blocks mouse-movement by constantly moving the mouse to position (1,0).
#### Blocking Mouse-movement ####
import threading
import mouse
import time
global executing
executing = True
def move_mouse():
#until executing is False, move mouse to (1,0)
global executing
while executing:
mouse.move(1,0, absolute=True, duration=0)
def stop_infinite_mouse_control():
#stops infinite control of mouse after 10 seconds if program fails to execute
global executing
time.sleep(10)
executing = False
threading.Thread(target=move_mouse).start()
threading.Thread(target=stop_infinite_mouse_control).start()
#^failsafe^
And then your original code here (the if statement and try/catch block are no longer necessary).
#### opening the video ####
import subprocess
import pyautogui
import time
subprocess.Popen(["C:\\Program Files\\Google\\Chrome\\Application\\chrome.exe",])
time.sleep(3)
pyautogui.write('www.youtube.com/watch?v=DLzxrzFCyOs', interval = 0.5)
pyautogui.hotkey('enter')
#### stops moving mouse to (1,0) after video has been opened
executing = False
Just a few notes:
The mouse-moving is hard to stop from outside of the program (it's basically impossible to close the program when it is executing, especially as the keyboard is also being blocked), that's why I put in the failsafe, which stops moving the mouse to (1,0) after 10 seconds.
(On Windows) Control-Alt-Delete does allow Task Manager to be opened and then the program can be force-stopped from there.
This doesn't stop the user from clicking the mouse, which can sometimes prevent the YouTube link from being typed in full (i.e. a new tab can be opened)
See a full version of the code here:
https://pastebin.com/WUygDqbG

you could do something like this to block both keyboard and mouse input
from ctypes import windll
from time import sleep
windll.user32.BlockInput(True) #this will block the keyboard input
sleep(15) #input will be blocked for 15 seconds
windll.user32.BlockInput(False) #now the keyboard will be unblocked

Here's a function for blocking keyboard and mouse input. You can pass a number to the blockMouseAndKeys function to adjust the timeout period:
import os
import time
import pyautogui
from threading import Thread
from keyboard import block_key
def blockMouseAndKeys(timeout=5):
global blocking
blockStartTime = time.time()
pyautogui.FAILSAFE = False
blocking = True
try: float(timeout)
except: timeout = 5
def blockKeys(timeout):
global blocking
while blocking:
if timeout:
if time.time()-blockStartTime > timeout:
print(f'Keyboard block timed out after {timeout}s.')
return
for i in range(150):
try: block_key(i)
except: pass
def blockMouse(timeout):
global blocking
while blocking:
def resetMouse(): pyautogui.moveTo(5,5)
Thread(target=resetMouse).start()
if timeout:
if time.time()-blockStartTime > timeout:
print(f'Mouse block timed out after {timeout}s.')
return
def blockTimeout(timeout):
global blocking
time.sleep(timeout)
blocking = False
pyautogui.FAILSAFE = False
print('Done blocking inputs!')
print('Blocking inputs...')
Thread(target=blockKeys, args=[timeout]).start()
Thread(target=blockMouse, args=[timeout]).start()
Thread(target=blockTimeout, args=[timeout]).start()
blockMouseAndKeys(timeout=10)
os.startfile('https://www.youtube.com/watch?v=DLzxrzFCyOs')

how to update tkinter gui label with a thread?

I am new to Python tkinter . I have written the following code for my gui . I want to update my label 1 with received body message from rabbitmq . But i am facing issue once my gui get populate after that even i receive different message in body ,but its not able to update . Once i am closing the gui then again its coming with new value. I want my gui tkinter window to be constant and label should be refreshed on receiving new message in body.
import tkinter
from PIL import ImageTk, Image as PILImage
import datetime as dt
from tkinter import *
import pika
connection = pika.BlockingConnection(
pika.ConnectionParameters(host='localhost'))
channel = connection.channel()
channel.queue_declare(queue='hello')
def callback(ch, method, properties, body):
global myval
print(" [x] Received %r" % body)
window=Tk()
window.attributes('-fullscreen',True)
window.bind("<F11>", lambda event: window.attributes("-fullscreen",
not window.attributes("-fullscreen")))
window.bind("<Escape>", lambda event: window.attributes("-fullscreen",False))
top_left=Frame(window,width=200,height=200)
top_middle=Frame(window,width=550,height=200)
top_right=Frame(window,width=250,height=200)
middle_left=Frame(window,width=200,height=300)
middle_middle=Frame(window,width=300,height=300)
middle_right=Frame(window,width=300,height=300)
bottom_left=Frame(window,width=0,height=200)
bottom_middle=Frame(window,width=300,height=200)
bottom_right=Frame(window,width=300,height=200)
top_left.grid(row=0,column=0)
top_middle.grid(row=0,column=1)
top_right.grid(row=0,column=2,sticky=E+W)
middle_left.grid(row=1,column=0,padx=100,pady=100)
middle_middle.grid(row=1,column=1)
middle_right.grid(row=1,column=2)
bottom_left.grid(row=2,column=0)
bottom_middle.grid(row=2,column=1)
bottom_right.grid(row=2,column=2)
dte=Label(top_left, text="Date: "f"{dt.datetime.now():%a,%d/ %m/ %Y}",fg="black",font=("Arial Bold ",12 ))
dte.place(x=0,y=40)
lbl=Label(top_middle, text="Welcome to Smartcards Division",fg='#3333ff',font=("Arial Bold Italic",24 ))
lbl.place(x=0,y=30)
logo_path="logo.jpg"
logo = ImageTk.PhotoImage((PILImage.open(logo_path)).resize((280,100),PILImage.ANTIALIAS))
logo_panel = Label(top_right,image = logo)
logo_panel.place(x=10,y=30)
string_clsname=str(body.decode())
lblxt=StringVar()
lbl1=Label(middle_left, textvariable=lblxt,fg='#ff6600',font=("Arial Bold Italic",16))
lblxt.set("Hello "+string_clsname+" Sir")
lbl1.place(x=0,y=100)
path = "NewPicture_Copy.jpg"
image = ImageTk.PhotoImage((PILImage.open(path)).resize((250,250),PILImage.ANTIALIAS))
panel = Label(middle_middle,image = image,borderwidth=5, relief="ridge")
panel.pack()
lbl2=Label(bottom_middle, text="\u00a9"+"2020-Smartcards Division",fg='black',font=("Helvetica",8))
lbl2.place(x=0,y=0)
window.title('Image Classification')
window.mainloop()
channel.basic_consume(
queue='hello', on_message_callback=callback, auto_ack=True)
print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()

At a base level, you need:
Separate threads of execution,
for separate tasks (that must run concurrently).
A way for the threads to communicate with each other;
while avoiding race conditions
(like modifying a variable in one thread,
while another thread is reading it).
Here you can e.g. use mutexes/locks, message-passing, etc.
import tkinter as tk
from collections import deque
from threading import Thread
from random import randint
from time import sleep
# Starting out (this is the main/gui thread).
root = tk.Tk()
label = tk.Label(root, text='Original text')
label.pack()
# Means of communication, between the gui & update threads:
messageQueue = deque()
# Create a thread, that will periodically emit text updates.
def emitText(): # The task to be called from the thread.
while(True): # Normally should check some condition here.
messageQueue.append(f'Random number: {randint(0, 100)}')
sleep(1) # Simulated delay (of 1 sec) between updates.
# Create a separate thread, for the emitText task:
thread = Thread(target=emitText)
# Cheap way to avoid blocking # program exit: run as daemon:
thread.setDaemon(True)
thread.start() # "thread" starts running independently.
# Moving on (this is still the main/gui thread).
# Periodically check for text updates, in the gui thread.
# Where 'gui thread' is the main thread,
# that is running the gui event-loop.
# Should only access the gui, in the gui thread/event-loop.
def consumeText():
try: label['text'] = messageQueue.popleft()
except IndexError: pass # Ignore, if no text available.
# Reschedule call to consumeText.
root.after(ms=1000, func=consumeText)
consumeText() # Start the consumeText 'loop'.
root.mainloop() # Enter the gui event-loop.
See also:
queue.Queue
"collections.deque is an alternative implementation of
unbounded queues with fast atomic append() and popleft()
operations that do not require locking."
collections.deque
threading.Thread

Python GUI freezes or closes while trying to update the button label text

I am trying to read a string from the ubuntu terminal and set that string as a label of a button. It works perfectly for some iteration and then freezes or closes with error. I couldn't find any pattern about when it freezes or closes. I am using gtk libraries and python 2.7.
A screenshot of the UI after it has frozen can be seen below.
As seen in the above screenshot, it has successfully updated the value 234, 56 and then exited with error after receiving 213 string. You can also observe that the button in the UI also has 213 value.
Sometimes the UI just freezes without displaying any errors or exiting.
I have used the below codes
1. thread.py ( main program called from terminal )
import thread
import time
import gui2
import vkeys1
import os
try:
thread.start_new_thread( vkeys1.main, ( ) )
thread.start_new_thread( gui2.main, ( ) )
except:
print "Error: unable to start thread"
# To stop this script from closing
os.system("mkfifo d1 2> error.log")
fd = os.open('d1', os.O_RDONLY)
ch = os.read(fd,1) # No writer
2. vkeys1.py ( It reads the input from terminal and calls textinit() )
import gui2
def main() :
while True:
try :
gui2.ch = str(input('\nInput a string : '))
gui2.textinit()
except :
print(" \n\n Exception!! \n\n")
3. gui2.py ( Updates the button label )
from gi.repository import Gtk, GdkPixbuf, Gdk, GLib
import Image
import os, sys
import time
import vkeys1
import threading
global ch # ch is used at vkeys1.py to store the input
ch = 'dummy content'
button0 = Gtk.Button(label="Initially empty")
class TableWindow(Gtk.Window):
def __init__(self):
Gtk.Window.__init__(self, title="String retrieval widget")
self.set_size_request(500,200)
self.connect_after('destroy', self.destroy)
self.main_box=Gtk.VBox()
self.main_box.set_spacing(5)
self.label = Gtk.Label(" ")
table = Gtk.Table(7,4, True)
self.add(self.main_box)
self.main_box.pack_start(self.label, False, False, 0)
self.main_box.pack_start(table, False, False, 0)
table.attach(button0, 0, 4, 0, 1)
self.show_all()
def destroy(window, self):
Gtk.main_quit()
def textinit(): # called from vkeys1.py
class Thrd(threading.Thread) :
def __init__(self) :
threading.Thread.__init__(self)
print('\nReceived string')
print(str(ch))
print('\n')
button0.set_label(str(ch)) # Button label updated here
Thrd2 = Thrd()
Thrd2.start()
return
def main():
app=TableWindow()
app.set_keep_above(True)
app.set_gravity(Gdk.Gravity.SOUTH_WEST)
Gtk.main()
if __name__ == "__main__":# for any error exit
sys.exit(main())
The above codes can be run by typing python thread.py (after creating the above 3 files off-course). Please suggest any solution to overcome this freezing problem.

The most likely cause of the crash is that your code invokes GTK code from threads other than the thread that runs the main loop, which the documentation states is not allowed.
To resolve the issue, replace the call of gui2.textinit() with GLib.idle_add(gui2.textinit) (note the lack of parentheses after textinit).
Several remarks about the code:
The generic exception handler is masking exceptions that occur. Remove it, and you will see a useful traceback when something goes wrong.
If you are running under Python 2, you probably want to change input to raw_input, otherwise the code chokes on any input that is not a valid Python expression.
textinit creates a thread object that never runs an actual thread. When inheriting from threading.Thread, one must override the run function, which will be invoked in the new thread once start() is called. Doing the work in the constructor accomplishes nothing.
thread.start_new_thread is a low-level API that should not be used in normal circumstances and that is demoted to _thread in Python 3. Instead of thread.start_new_thread(fn, ()), use threading.Thread(target=fn), which has the same meaning, and also returns a Thread object.

Python Serial Port with threading - freezing computer

Okay, time for another question/post...
So currently i am trying to develop a simple python program that has a webkit/ webpage view and a serial port interface.. Not that it should matter, but this is also running on a raspberry pi.
The following code works fine.. But it will freeze the system as soon as i uncomment the serial port line that you can see commented out.
The day has been long and this one for some reason has my brain fried.. Python is not my strongest point, but mind you this is just a quick test script for now... Yes i have used google and other resources...
#!/usr/bin/env python
import sys
import serial
import threading
import time
from PyQt4.QtCore import *
from PyQt4.QtGui import *
from PyQt4.QtWebKit import *
sURL = ""
sURL2 = ""
objSerial = serial.Serial(0)
def SerialLooper():
global objSerial
if objSerial.isOpen() == True:
print("is_responding")
#objSerial.write("is_responding")
time.sleep(10)
SerialLooper()
class TestCLASS(object):
def __init__(self):
global sURL
global sURL2
global objSerial
objSerial = serial.Serial(0)
sURL = "http://localhost/tester"
app = QApplication(sys.argv)
webMain = QWebView()
webMain.loadFinished.connect(self.load_finished)
webMain.load(QUrl(sURL))
webMain.show()
thread = threading.Thread(target=SerialLooper)
thread.start()
sys.exit(app.exec_())
def load_finished(boolNoErrors):
global sURL
print("Url - " + sURL)
#something here
#something else here
newObjClass = TestCLASS()
EDIT
Futher on this, it appears its not the multithreading but the serial.write()

It has been a while since I used serial, but IIRC it is not threadsafe (on Windows at least). You are opening the port in the main thread and performing a write in another thread. It's a bad practice anyway. You might also consider writing a simple single-threaded program to see if the serial port is actually working.
PS Your program structure could use some work. You only need one of the global statements (global objSerial), the rest do nothing. It would be better to get rid of that one, too.
And the recursive call to SerialLooper() will eventually fail when the recursion depth is exceeded; why not just use a while loop...
def SerialLooper():
while objSerial().isOpen(): # Drop the == True
# print something
# write to the port
# Sleep or do whatever

gtk infinite loop exit

I have a script which has a record and stop button, the record button does an infinite loop, but it also blocks the other button (stop button). All I wanted to build is a process which starts at click of record button and stops are click of stop button. Here is the script:
# -*- Mode: Python; coding: utf-8; indent-tabs-mode: nil; tab-width: 4 -*-
### BEGIN LICENSE
# This file is in the public domain
### END LICENSE
from locale import gettext as _
from gi.repository import Gtk # pylint: disable=E0611
import logging
logger = logging.getLogger('recordme')
from recordme_lib import Window
from recordme.AboutRecordmeDialog import AboutRecordmeDialog
from recordme.PreferencesRecordmeDialog import PreferencesRecordmeDialog
class RecordmeWindow(Window):
__gtype_name__ = "RecordmeWindow"
record = False
def finish_initializing(self, builder): # pylint: disable=E1002
"""Set up the main window"""
super(RecordmeWindow, self).finish_initializing(builder)
self.AboutDialog = AboutRecordmeDialog
self.PreferencesDialog = PreferencesRecordmeDialog
# Code for other initialization actions should be added here.
self.button1 = self.builder.get_object('button1')
self.button2 = self.builder.get_object('button2')
def on_button1_clicked(self, widget):
while(not self.record):
print 'button1 clicked'
while gtk.events_pending():
gtk.main_iteration(False)
Any ideas about this problem ?

I encountered similar programs in WX, which is also event based. The best (and possibly only) way I found to solve the problem is to create a function that runs on a timer during the main loop. Mine ran periodically, but you could also just set it to wait and close the loop when you run your function. In GTK, you have to do this with another module, "gobject". Here is an example of a method that runs periodically in GTK.
import gobject
class gtk_object(object):
def __init__(self):
gobject.timeout_add(100, self.my_function)
def my_function(self):
#do something here, like stopping the loop or having a timer to stop the loop
return True

Assuming your record functionality is cpu-intensive and/or may block and/or needs soft realtime assurance, I would recommend moving it off to a separate "worker" thread.
Then, create a window and your buttons.
Here, when "record" is clicked, I signal the worker to start recording; when "stop" is clicked, signal worker to stop; Optionally, when stop is clicked, terminate the main loop if you want your app to exit.
Additional control logic to terminate the app when window is closed and terminate the worker thread correctly is at the very bottom.
#!/usr/bin/env python
import time
import logging
import threading
from gi.repository import Gtk
class Worker(threading.Thread):
should_record = False
quit = False
def run(self):
while not self.quit:
if self.should_record:
logging.warn("recording...")
# cpu-intensive code here
else:
time.sleep(0.1)
class MainWindow(Gtk.Window):
def __init__(self):
super(MainWindow, self).__init__()
self.worker = Worker()
self.worker.start()
hb = Gtk.Box()
self.add(hb)
record = Gtk.Button("Record")
stop = Gtk.Button("Stop")
hb.add(record)
hb.add(stop)
def command(arg):
self.worker.should_record = arg
record.connect("clicked", lambda _b: command(True))
stop.connect("clicked", lambda _b: command(False))
# optional, if you want to quit the app on stop as well
stop.connect("clicked", lambda _b: Gtk.main_quit())
if __name__ == "__main__":
main = MainWindow()
try:
# optional, if you want to support close window to quit app
main.connect("delete-event", Gtk.main_quit)
main.show_all()
Gtk.main()
finally:
main.worker.quit = True
main.worker.join()
old stuff
Ideally you wan to use Gtk.main() instead of Gtk.main_iteration() in Gtk+ 3.
In Gtk+ 2, module name was gtk rather than gi.repository.Gtk.
Then you can quit wit with:
Gtk.main_quit
def main_quit()
The Gtk.main_quit() function terminates the current main loop level
started by the most recent call to the Gtk.main() function. The
nesting level of the main loop is reduced by calling this function.
You can have several nested main loops, in which case, you'd have to quit each of those.
Alternatively you can also use gtk_dialog.run() then default action for a button is to exit the loop.

GTK+ (as most UI toolkits) is event-based. That means it runs internal "event loop" - a loop that collects and processes events, such as handling user input and redrawing windows. All event handlers are dispatched from main loop. In order to process events, loop must be "spinning".
In your example, you are blocking main loop:
def on_button1_clicked(self, widget):
while(not self.record):
print 'button1 clicked'
as long as this function does not finish, control does not return to main loop so it cannot process other events, or redraw windows.
You can add this snippet form PyGTK FAQ in order to allow main loop to process event in the meantime:
while gtk.events_pending():
gtk.main_iteration(False)