CODEWITHSUNDEEP
pythonpython-3.x
johnlee20181218
johnlee20181218

Reputation: 31

Python keyboard library ignoring time.sleep()

the question started of with an anki addon that is being written in python, and in the middle of tuning my function (i thought the functionality was flawed due to things not registering, so i added timeouts but it turns out to be other stuff). i noticed that everything from the keyboard library seems to ignore the time.sleep(), wait the total time, then burst out everything at once.

def someFunction(self):
  keyboard.send("ctrl+a")
  time.sleep(1)
  keyboard.send("ctrl+c")
  time.sleep(3)
  rawText = pyperclip.paste()
  newText = string_manipulation(rawText)
  keyboard.write(newText)

this is the code from my project. which is equivalent to below:

time.sleep(4) #1+3=4
keyboard.send("ctrl+a")
keyboard.send("ctrl+c")
keyboard.write(newtext)

I thought it might be because i bundled the library myself. so i went to use notepad++, plain editor with cmd to recreate the problem. and to make it easier to observe, i made the time difference very obvious in between the sleep.

def example():
  time.sleep(3)
  keyboard.send("a")
  time.sleep(1)
  keyboard.send("b")
  time.sleep(10)
  keyboard.send("c")

so when running the script in cmd, and staying in the cmd, it waits for 11 seconds then have an outburst of "abc".

but quickly switch to a text editor after executing the script in cmd, then in the text editor it treats the time.sleep() normally.

system: windows python version: 3.6.4 keyboard library version: 0.13.4 (latest install, on 10.06.2019)

so my question follows:

  1. what is the cause python to treat time.sleep() in a chunky fashion.
  2. if it is the keyboard library itself, then is there ways around it? (in the documentation it mentioned sometimes the library can plain out not work at all in other applications)
  3. if there is no other way around it, is there other alternative libraries? (option that isnt pyautogui, because i've tried so hard to bundle it into my project, but the imports of this library loops back on itself all the time. causing everything to break.)

p.s. for the python experts and pyqt addon experts out there, I know this is far from optimal to achieve this goal, i am still learning on my own, and very new to programming, so if there are any advises on other means of accomplishing it. I would love to hear your ideas on it! :)

Upvotes: 3

Views: 238

Answers (1)

Fauxcuss
Fauxcuss

Reputation: 468

I'm new to Python myself so I can't give you a pythonic answer, but in C/C++ and other languages I've used, what Sleep() does is tell the system, "Hand off the rest of my processing time slice with the CPU back to the system for another thread/process to use, and don't give me any time for however many seconds I specified."

So:

    time.sleep(3)
    keyboard.send("a")
    time.sleep(1)
    keyboard.send("b")
    time.sleep(10)
    keyboard.send("c")

This code first relinquishes processing to immediately and for about three seconds, and then it's going to come back to your thread eventually and keyboard.send("a") is going to be called. It probably ends up tossing the "a" on a queue of characters to be sent to the keyboard, but then you immediately tell your process to time.sleep(1) which interrupts the flow of your code and gives up approximately one second of time to the other threads/processes, then you send "b" to the queue and relinquish about 10 more seconds to the other threads/processes.

When you finally come back to the keyboard.send("c") it's likely that you have "a" and "b" still in the queue because you never gave the under-the-hood processing a chance to do anything. If this is the main thread, you could be stopping all kinds of messages from being processed through the internal message queue, and now since you're not calling sleep anymore, you get "a", "b" and "c" sent to the keyboard out of the queue, seemingly all at once.

That's my best guess based on my old knowledge of other languages and how operating systems treat events being "sent" and message queues and those sorts of things.

Good luck! I could be completely wrong as to how the Python engine works, but ultimately this has to get down to the system level stuff and in Windows, there is a message queue that posts events like this into the queue to be processed.

Perhaps you can spin off another thread where the send and sleep's happen, so that in the main thread, where the system message processing usually exists, that can keep ticking along and getting your characters to the keyboard. This way you're not putting the main thread that has lots of work to do to give up it's CPU time.

Upvotes: 3

Related Questions