Copy data from the clipboard on Linux, Mac and Win

Question

I am trying to create a script in Python that will collect data put in the clipboard by the user and preferably save it as a list or in a text file or string/array/variable to work with later on.

This should work on Linux all versions (I would assume Ubuntu), Mac OS all versions and Windows all versions. I am not sure if 32bit and 64bit systems have different ways of accessing the data at the clipboard, if they do I guess it would be safe to make this work for the 32bit versions only so people running the 64bit versions can fall back onto the 32bit version of the OS.

The tricky part, apart from this having to work on the mentioned OS, is that I would like the script to run as long as the user does not stop it and while it runs all the data copied into the clipboard by the user is being copied to a list or in a text file or string/array/variable.

Of course there is a time limit at which the user can input data into the clipboard so I was thinking of having a loop scanning the clipboard every second or every 500 milliseconds, check if the content has changed, and if it has, copy it, otherwise don't copy it.

Is there a unified way or module that does this on all different OS or would it be better to write separate scripts for this task for the various OS?

The thing is, this is part of a bigger project that I would like to make work on Linux, Mac and Windows, so having those three options covered and then use Python code that can be used across the mentioned OS for the rest of the script/project would be ideal. Am I asking too much in general from this script concerning it having to work on Linux, Mac and Windows?

Answer 1

The xerox library supports Linux, Mac OS X, and Windows.

Note that it's a very bad idea to perform any action in short (< a minute) intervals, because that makes modern processors wake up regularily. You may want to use the respective operating system's APIs to register a callback once the clipboard changes.

Answer 2

You could use a GUI toolkit such as Qt to get a portable clipboard API. That said it might be a little overkill to use a whole GUI toolkit just for this. (Unless, of course, you're also going to use it to make a GUI.)

That said, clipboard APIs dealing with plain text should be reasonably simple to make your own abstraction over.

For instance, on OS X you can use PyObjC (which is installed along with OS X) to get plain-text contents of a clipboard:

from AppKit import NSPasteboard
from LaunchServices import 
pb = NSPasteboard.generalPasteboard()
text = pb.stringForType_(kUTTypeUTF8PlainText)

CPU architectures

A 32-bit native app on a 64-bit OS will be accessing the same clipboard as a 64-bit one. If you need to support both architectures of an OS, and aren't writing a driver, for Windows it's okay to ship a 32-bit binary; for Linux you'll likely have to do both versions; for OS X, it should be reasonably safe to ship a 64-bit version, all Macs since mid-2007 have had 64-bit CPUs and the OS support is there since Leopard. A Python script will, on Linux, probably be executed by a Python installation from the distribution package manager, whose bitness will match the system, so you don't necessarily need to worry about that.

Answer 3

Polling is NOT robust/reliable.

You cannot determine if data has changed (on windows anyway) without pasting it into a buffer for inspection. This requires opening the clipboard. If you do this in a loop, you're going to collide with other apps. i.e. the app where the user is copying another item onto the clipboard. This will explode with an "cannot open clipboard" or "out of memory" error. This approach will not work reliably/robustly. You need to use proper clipboard monitoring APIs in the various platforms.

Answer 4

You're probably better off using a more advanced gui toolkit than Tk, but it's in the standard library, so it's available everywhere.

As a really simple example:

import Tkinter
root = Tkinter.Tk()
root.withdraw() # Hide the main window (optional)
text_in_clipboard = root.clipboard_get()
print text_in_clipboard