ReadKey() doesn't track keystrokes in other windows or instances - powershell

I wrote a simple script to track keys being pressed and released as shown below:
$j = 0
while($j -lt 10000){
$PressedKey = $Host.UI.RawUI.ReadKey("NoEcho,IncludeKeyDown,IncludeKeyUp")
$PressedKey
continue
}
When I run it and start pressing keys, it works. However when I switch to a different Instance or Window and start pressing keys, it stops giving an output. I assume this is because it stops tracking the keystrokes, can't produce an output, or both. Does anyone know any good alternatives to ReadKey() to how to make it track keystrokes on other Windows and/or Instances
I believe this is PowerShell 7
thx.

The object $Host refers to the current PowerShell console host. Therefore, connecting to the ReadKey() method will only return the current PowerShell host keystrokes, and that is the point of the ReadKey() method, return the current host's keystrokes so that other functions (e.g. PSReadline) can act on them.
If you want to globally respond to keystrokes across applications, I personally recommend AutoHotKey. It is fairly easy to create a script that will detect a key combination and perform an action. It is fast and easy to use and I have dozens of key combinations that I have scripted and use every day.
It is possible to create PowerShell scripts that globally hook into keyboard keystrokes and respond to events, but this is beyond the scope of a SO post.

Related

Remove preset binding in fish shell

I am unable to remove the default binding in Fish shell for CTRL + p.
I want to activate separate "background" app outside of the terminal using the CTRL+P shortcut.
I have tried:
bind --erase \cp up-or-search
However the binding remains. How can I remove the preset bindings? The documentation does not mention it.
I want this shortcut to propagate up to the parent process rather than Fish swallowing it and reacting to it.
That's not how it works.
If by "parent process" you mean the terminal, that gets first dibs on every key. It gets to decide what is passed on and what isn't.
If by "parent process" you mean an in-terminal process that started fish: That typically stays in the background and doesn't read any keys at all.
And fish will (and has to) read all input it receives, even if it then decides to do nothing. Reading it is how it finds out what it has to do, and it cannot stuff the input back.
And the terminal has no idea what the processes running inside it have bound or not, so it also can't decide to send keys that it knows the shell will do something with and keep others for itself.
Your mental model is incorrect.
How can I remove the preset bindings?
To erase a preset binding, you could run
bind --erase --preset \cp
However, you would have to arrange for that to be run after the binding has actually been set up. You might want to store it in a function called fish_user_key_bindings. Fish runs that after it sets up the bindings, whenever it does it (e.g. if you switch to vi-mode it'll rerun it).
Typically to disable a binding you would rather make your own that does nothing, like
bind \cp true
Not that this would help what you want to do, see above.

programmatically press an enter key after starting .exe file in Matlab

In Matlab I can start external .exe files that sometime have a pop up that requires an enter key pressed. For example:
system('C:\Program Files (x86)\WinZip\WINZIP32.EXE')
will start Winzip, and then in order to use it you need to pass the "buy now" pop up window by pressing enter.
Now my problem is not with winzip, I only gave it as an example (i use winrar anyway :).
How can I programmatically press an enter key in Matlab in such cases ? (I use win 7)
Can an event listener be used to solve that?
EDIT: The java.awt.Robot class indeed works on explorer, but not on any software that has a pop up window with an OK button that needs to be pressed. I don't know why it doesn't work for that. I gave the winzip example because I assume everybody has winzip/winrar installed in their machine. The actual software I have is different and irrelevant for the question.
There is a way using Java from Matlab, specifically the java.awt.Robot class. See here.
Apparently there are two types of programs, regarding the way they work when called from Matlab with system('...'):
For some programs, Matlab waits until the program has finished before running the next statement. This happens for example with WinRAR (at least in my Windows 7 machine).
For other programs this doesn't happen, and Matlab proceeds with the next statement right after the external program has been started. An example of this type is explorer (the standard Windows file explorer).
Now, it is possible to return execution to Matlab immediately even for type 1 programs: just add & at the end of the string passed to system. This is standard in Linux Bash shell, and it also works in Windows, as discussed here.
So, you would proceed as follows:
robot = java.awt.Robot;
command = '"C:\Program Files (x86)\WinRAR\WinRAR"'; %// external program; full path
system([command ' &']); %// note: ' &' at the end
pause(5) %// allow some time for the external program to start
robot.keyPress (java.awt.event.KeyEvent.VK_ENTER); %// press "enter" key
robot.keyRelease (java.awt.event.KeyEvent.VK_ENTER); %// release "enter" key
If your applications are only on Windows platform, you can try using .net objects.
The SendWait method of the SendKeys objects allows to send virtually any key, or key combination, to the application which has the focus, including the "modifier" keys like Alt, Shift, Ctrl etc ...
The first thing to do is to import the .net library, then the full syntax to send the ENTER key would be:
NET.addAssembly('System.Windows.Forms');
System.Windows.Forms.SendKeys.SendWait('{ENTER}'); %// send the key "ENTER"
If you only do it once the full syntax is OK. If you plan to make extensive use of the command, you can help yourself with an anonymous helper function.
A little example with notepad
%% // import the .NET assembly and define helper function
NET.addAssembly('System.Windows.Forms');
sendkey = #(strkey) System.Windows.Forms.SendKeys.SendWait(strkey) ;
%% // prepare a few things to send to the notepad
str1 = 'Hello World' ;
str2 = 'OMG ... my notepad is alive' ;
file2save = [pwd '\SelfSaveTest.txt'] ;
if exist(file2save,'file')==2 ; delete(file2save) ; end %// this is just in case you run the test multiple times.
%% // go for it
%// write a few things, save the file then close it.
system('notepad &') ; %// Start notepad, without matlab waiting for the return value
sendkey(str1) %// send a full string to the notepad
sendkey('{ENTER}'); %// send the {ENTER} key
sendkey(str2) %// send another full string to the notepad
sendkey('{! 3}'); %// note how you can REPEAT a key send instruction
sendkey('%(FA)'); %// Send key combination to open the "save as..." dialog
pause(1) %// little pause to make sure your hard drive is ready before continuing
sendkey(file2save); %// Send the name (full path) of the file to save to the dialog
sendkey('{ENTER}'); %// validate
pause(3) %// just wait a bit so you can see you file is now saved (check the titlebar of the notepad)
sendkey('%(FX)'); %// Bye bye ... close the Notepad
As explained in the Microsoft documentation the SendKeys class may have some timing issues sometimes so if you want to do complex manipulations (like Tab multiple times to change the button you actually want to press), you may have to introduce a pause in your Matlab calls to SendKeys.
Try without first, but don't forget you are managing a process from another without any synchronization between them, so timing all that can require a bit of trial and error before you get it right, at least for complex sequences (simple one should be straightforward).
In my case above for example I am running all my data from an external hard drive with an ECO function which puts it into standby, so when I called the "save as..." dialog, it takes time for it to display because the HDD has to wake up. If I didn't introduce the pause(1), sometimes the file path would be imcomplete (the first part of the path was send before the dialog had the focus).
Also, do not forget the & character when you execute the external program. All credit to Luis Mendo for highlighting it. (I tend to forget how important it is because I use it by default. I only omit it if I have to specifically wait for a return value from the program, otherwise I let it run on its own)
The special characters have a special code. Here are a few:
Shift +
Control (Ctrl) ^
Alt %
Tab {TAB}
Backspace {BACKSPACE}, {BS}, or {BKSP}
Validation {ENTER} or ~ (a tilde)
Ins Or Insert {INSERT} or {INS}
Delete {DELETE} or {DEL}
Text Navigation {HOME} {END} {PGDN} {PGUP}
Arrow Keys {UP} {RIGHT} {DOWN} {LEFT}
Escape {ESC}
Function Keys {F1} ... {F16}
Print Screen {PRTSC}
Break {BREAK}
The full list from Microsoft can be found here
There is a small javascript utility that simulates keystrokes like this on the Windows javascript interpreter.
Just create a js file with following code:
var WshShell = WScript.CreateObject("WScript.Shell");
WshShell.SendKeys(WScript.Arguments(0));
then call it from Matlab after the necessary timeout like this:
system('c:\my\js\file\script.js {Enter}');
Can't test here now, but I think this should work...
If you need to run a console-only program in a context that permits full DOS redirection, you can create a file called, say, CR.txt containing a carriage return and use the '<' notation to pipe the value into the program.
This only works if you can provide all the keyboard input can be recorded in the file. It fails dismally if the input has to vary based on responses.
An alternative is to duplicate the input (and possibly output) stream(s) for the program and then pipe data into and out of the program. This is more robust and can permit dynamic responses to the data, but will also likely require substantial effort to implement a robot user to the application.
Rog-O-Matic is an example of a large application completely controlled by a program that monitors screen output and simulates keyboard input to play an early (1980s) ASCII graphic adventure game.
The other responses will be required for GUI-based applications.
Python package pywinauto can wait any dialog and click buttons automatically. But it's capable for native and some .NET applications only. You may have problems with pressing WPF button (maybe QT button is clickable - not checked), but in such case code like app.DialogTitle.wait('ready').set_focus(); app.DialogTitle.type_keys('{ENTER}') may help. Your case is quite simple and probably some tricks with pywinauto are enough. Is your "app with popup" 64-bit or 32-bit?
wait and wait_not functions have timeout parameter. But if you need precisely listener with potentially infinite loop awaiting popups, good direction is global Windows hooks (pyHook can listen mouse and keybd events, but cannot listen dialog opening). I'll try to find my prototype that can detect new windows. It uses UI Automation API event handlers... and... ops... it requires IronPython. I still don't know how to set UI Automation handler with COM interface from standard CPython.
EDIT (2019, January): new module win32hooks was implemented in pywinauto a while ago. Example of usage is here: examples/hook_and_listen.py.

How to stop a Matlab script but don’t kill the process? [duplicate]

This question already has answers here:
Stop and continue execution from debugger possible?
(6 answers)
Closed 8 years ago.
Strg+C stops and kills a Matlab script (at least sometimes). But is there a way to stop a Matlab, take a look at some variables and continue the calculation?
I am not talking about just setting a breakpoint. I want my script, let’s say run for couple hours come back to it hit some buttons that stops the calculations take a look at some variable and then continue the calculation.
I tried to find out if there is some shortcut key for this – I am quite sure there isn’t.
Now I was thinking about including an if-case that looks if a certain button was pressed by the user. If so there would be a useless k=0 line and a breakpoint on it. And if no one is pressing this button the loop would continue. But this is where my limited Matlab knowledge leaves me. I don’t know if there is a way to ask for a user-button press but don’t wait for a button press like in the function input. Also I just have a running script, I don’t have any GUI.
To drop to the command prompt you need the command keyboard and then type return when you have finished (you don't need a breakpoint). The tricky bit is how to trigger it. There a few options. The easiest is to open a figure window. The following code halts the process when any key is pressed.
keyDownListener=#(src,event) keyboard;
fig = figure;
drawnow
set(fig,'KeyPressFcn',keyDownListener)
for p=1:10000
%do some thing
end
You can modify this to test for a specific key since the keypress is contained within the event struct.
To use no figure gui at all its more of a problem. I'm not aware of a non blocking keyboard input method. A mex file the runs kbhit() in C might do it, but kbhit() is not standard C so it would only work on Windows. An easier option maybe to test for the presence of a file.
for p=1:100000
if exist(fullfile(pwd,'halt.tmp'),'file')
keyboard
end
%do something here
end
This drops to the debug console when halt.tmp is created in the current directory.
Other potential methods could involve using multiple threads to read 'input' (either the Parallel computer toolbox or undocumented Java code), or using http://psychtoolbox.org/ as mentioned by #bdecaf

autohotkey does not exist in current keyboard layout - solution examples

I have written a python script for my co-workers, and then created an autohotkey script to run it every time someone presses Ctrl+LShift+Y. Looks something like this:
^+y::Run helper.py
The python script is fine, but the ahk script doesn't work on all the computers. Sometimes it works fine, and sometimes you get this error:
^+y does not exist in current keyboard layout
Now, searching the web this seems to be a problem with multi-language keyboards (we're using both Hebrew and English), because different languages means a different layouts (I guess?). I also found someone explaining that to solve this you need to use scan codes instead of the usual ^ and + and so on (I'd link to it but I cannot seem to find it now).
This all vaguely makes sense to me on a theoretical level, but when I want to realize it with actual code, I don't really know what to do. To me it seems as if this topic is hardly discussed (with the few exceptions being lacking in examples or hard to understand), so I'd love an answer that would include the following:
some simple way of determining the scan code for a key. This should preferably be a pythonic solution (and just out of curiosity, I'd love to know how to do this with linux as well). This is probably the easier part (but I think is an inherent part of a complete answer).
This is the important part: examples of how you implement that scan code in an autohotkey script, including edge-cases (if there are any).
Question 1
As you want to use the key with autohotkey, it makes sense to use autohotkey detect the key in the first place. Obviously this method works only on windows where autohotkey is running.
Write a Autohotkey script with this line and run it.
#InstallKeybdHook
Press the key you want to examine.
Open the script menu by right clicking the icon of the script in the right lower corner of your screen.
Select OPEN, then from the Menu "View / Key history and script info"
There is a line for each keypress.
First column is the VK (Virtual key) code, next is the scancode.
For example for CAPSLOCK the VK is 14 and the Scancode 03a
Question 2:
#InstallKeybdHook
VK14::
msgbox, you pressed capslock!
return
OR
#InstallKeybdHook
SC03a::
msgbox, you pressed capslock!
return
both work.
Note that you can combine two keys into a hotkey by combining them with & (but not 3)
#InstallKeybdHook
RShift & SC03a::
msgbox, you pressed Rshift capslock!
return
You can modify a Scancode with + and ^
#InstallKeybdHook
^+SC02C::
msgbox, you pressed Ctrl Shift and Y(maybe)!
return
Further info about this is on the page "List of Keys, Mouse Buttons, and Joystick Controls" of the autohotkey help file that comes with the default installation.

Matlab pause function that returns the keystroke?

I'd like to use a function in some matlab scripts that would do the following:
Pause until user hits any single key
Return the key stroke hit by the user
The pause function doesn't work, because it doesn't return the user keystroke. The input function doesn't work, because it requires the "enter" key to be hit. The keyboard command dumps you into the full command line window which I don't want (although might be useful for future work). Note, there are ways to do this from figures, i.e. if a figure has focus, you can sniff keystrokes using the 'KeyPressFcn' handler. But I want to do this from scripts. Worst case, I can use the input command, but was hoping for something that required fewer keystrokes from the user.
I found this on MathWorks. Does it do what you want: http://www.mathworks.com/matlabcentral/fileexchange/7465-getkey