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How to get an application's version on macOS?

I am writing a simple script using python to be used on macOS BigSur. I was wondering if there is a way to find the version of an application using python. I know it's possible on Windows using PyWin32 library, however, I could not find anything for MacOS.

Thanks #sudden_appearance for the approach
import os
stream = os.popen('mdls -raw -name kMDItemVersion /Applications/Firefox.app')
targetVer = stream.read()
print(targetVer)

Python version of AddFontResource()

I'm currently trying to install fonts across a bunch of servers. I've been able to use a script to copy the fonts over and "install" them onto the server but I need to be able to access the fonts without having to turn off the server or log off the account.
I found Windows AddFontResource() which is done using C++, but is there an equivalent function in Python or Powershell?
(I've been using Python and Powershell to do checks and installations.)

Have you tried using the win32api library? It has the SendMessage() function which can be used in conjunction with the windll.gdi32.AddFontResource() in ctypes
For example installing a TTF font file:
import win32api
import ctypes
import win32con
ctypes.windll.gdi32.AddFontResourceA("C:\\Path\\To\\Font\\font.ttf")
win32api.SendMessage(win32con.HWND_BROADCAST, win32con.WM_FONTCHANGE)

pexpect: How to interact() over file object using newer version of pexpect library

pexpect has gone through big changes since the version provided by Ubuntu 15.04 (3.2). When installing newest version of pexpect using pip3, this minimal program that previously successfully gave terminal emulation over serial console does not work any more:
#!/usr/bin/python3
import serial
import pexpect.fdpexpect
ser = serial.Serial("/dev/ttyS0", baudrate=115200)
spawn = pexpect.fdpexpect.fdspawn(ser)
spawn.interact()
The newer API is missing interact() method in class pexpect.fdpexpect.fdspawn which used to be there.
Question: how is the newer version of pexpect (currently 4.2.1) supposed to be used to provide free manual interaction with file object (serial port in this case)?
Alternatively, question/work-around: I recognize I am using a bit heavy machinery for such a simple use case, any suggestions for other python libraries that can do the same as earlier version of pexpect could?
Code reading: Examples use pexpect.spawn(command_str) to get a spawn object which has interact() method; actually this pexpect.spawn() is the same as directly creating a pexpect.pty_spawn.spawn object which has this method. On the other hand, pexpect.fdpexpect.fdspawn() will construct a pexpect.fdpexpect.fdspawn class which is missing interact() method. Both of these spawn classes derive from pexpect.spawnbase.SpawnBase class. Based on my quick reading, this looks like regression that resulted from refactoring on the way to version 4.x.

Browsing the pexpect issues, found #351, #356, and the newly submitted #377. By my quick reading, it seems this is a regression that was brought by uncompleted refactoring along the way towards new major release version 4. There are three possible avenues:
Make sure to install older version:
$ pip3 install "pexpect<3"
(or make sure that the version installed by other system is 3.x).
Fix pexpect by yourself.
Use some other python library.
These avenues were all more or less hinted by github user #takluyver, apparently maintainer of pexpect in comment to issue #351:
#jquast any thoughts on what to do for this (and #356)? I feel bad that we've broken things people were doing with fdspawn, but I really don't want to make it inherit from the pty spawn class, and now that it works on Windows, I think it's important to preserve that too.
Maybe we should just say:
If you have legacy code that broke with Pexpect 4, downgrade to Pexpect 3.x (pip install pexpect<4)
If you're writing new code, use streamexpect instead of pexpect.

Text to Speech Library for Python using Windows 8.1 (SAPI)

I'm trying to create a simple program that will relay what I type as synthesized speech. I've tried pyttsx, it has been known to not work with python 3.x and it sure doesn't. I also tried using speech, but it interfered with the speech_recognition Library I'm using. I don't have any code to show since I don't even have a Library for it yet.
Running Python 3.4.2 32-bit on Windows 8.1 64-bit

According to this POST, considering that you are targeting the Windows platform, the following will work:
import win32com.client
speaker = win32com.client.Dispatch("SAPI.SpVoice")
speaker.Speak("Hello, it works!")

Importing a dll in python on Ubuntu

I am using python 2.6.5 on an Ubuntu intalled server.
I need to integrate an API for our applicaion, in that case, i needed to use a DLL given to me by the API provider. Their example of code about api integration is written in Visual Basic... I made a search on google and found some examples of using ctypes , and i try using cdll and pydll, which caused the following error...
OSError: /home//some.dll: invalid ELF header
One possibility is using IronPython, but i do not have much information about ironpython so i am not sure if it will handle my needs completely..
Is there any available module that let me use that dll on python (or aynthing that i am missing from the exixting ones). It is hard to upgrade my python version?

DLLs may be windows creatures, but if a DLL is 'pure .NET' and doesn't utilize executables specific to windows etc., then it can work often in Linux, through Mono. (mono ipy.exe).
Ironpython's System and similiar windows modules are customized to be os agnostic (to a untested degree).
I have successfully run NHibernate, FluentNHibernate, log4net, and a few other commonly used DLLS in Ubuntu.
import clr
import sys
sys.path.append(os.path.abspath('./DLL')) #where your dlls are
clr.AddReference('System')
clr.AddReference('FluentNHibernate')
from FluentNHibernate.Cfg.Db import PostgreSQLConfiguration
The key seems to be to import DLLs in this fashion. If a dll imports another (fluentnhibernate imports nhibernate), you don't need to import Nhibernate for example.

DLLs are Windows creatures. The only way you'll be able to use a DLL is by using a Windows build of Python. You'll be able to run Windows Python on Ubuntu by having Windows installed inside a virtual machine. You also might be able to run it using Wine.
An alternative, of course, is to ask your API provider if they have a Linux version of the API.

First, check if your DLL is a .NET Assembly file. An "Assembly DLL file" has nothing to do with the assembler. It's simply a way the .NET framework stores its bytecode inside a DLL file!
Do file library.dll in Linux. If it says something like this:
PE32 executable (DLL) (console) Intel 80386 Mono/.Net assembly, for MS Windows
then you're lucky: it's an assembly file. You can run it on Linux.
Install Mono. Install Python.NET. Forget IronPython: it's dead.
Now, in Python.NET, you can do this:
import clr
clr.AddReference('./library.dll')
# the library has just registered a namespace we can use
from LibraryName import *
but how do you know what to import?
Auto-complete.
Or use monop tool to inspect the DLL like this:
$ monop -r library.dll
Assembly Information:
LibraryName
Version=9.9.3.0
Culture=neutral
PublicKeyToken=null
LibraryName.ClassName
...
$ monop -r library.dll LibraryName.ClassName
public class ClassName {
public ClassName (string inputString);
...
}
and it will tell you everything about that library