Embed interactive console?

[lumbo7332]

I'm trying to run a function that prints to STDOUT and requires user interaction, within a widget. So far I have a class called EmbeddedTerminal, and that is a subclass of QTextEdit. Then it has a function called run_func that takes a function name, and *args and **kwargs. Then it runs that function, redirects the output, and sets the QTextEdit to the output of the function. Problem is, that only works for a function that isn't interactive. I figure I have to do something with threading.

This is what I have so far, but it's not setting the QTextEdit

from contextlib import redirect_stdout
from io import StringIO

from PyQt5.QtWidgets import QTextEdit
from PyQt5.QtCore import QObject, QThread, pyqtSignal


class EmbeddedTerminal(QTextEdit):
    def __init__(self, parent):
        super(EmbeddedTerminal, self).__init__(parent)

    def run_func(self, func, *args, **kwargs):
        self.thread = QThread()
        self.worker = TerminalWorker(func, args, kwargs)
        self.worker.moveToThread(self.thread)
        self.thread.started.connect(self.worker.run)
        self.worker.progress.connect(self.update_terminal)

    def update_terminal(self, text):
        self.setText(text)


class TerminalWorker(QObject):
    finished = pyqtSignal()
    progress = pyqtSignal(str)

    def __init__(self, func, args, kwargs):
        QObject.__init__(self)
        self.func = func
        self.args = args
        self.kwargs = kwargs

    def run(self):
        with redirect_stdout(StringIO()) as f:
            self.func(self.args, self.kwargs)
        output = f.getvalue()
        self.progress.emit(output)

Source code, if it's helpful.

[eyllanesc]

@lumbo7332 what is interactive function? please provide a minimal and verifiable example.

Note: You should not modify (or access) GUI elements and directly related elements (such as models associated with views) from another thread as they are not thread-safe. That has nothing to do with the stdout redirect but with a rule set by Qt.

[lumbo7332]

@eyllanesc I mean something that uses the input() function. Although, my current implementation with the worker doesn't seem to set the QTextEdit , no matter what function I use (e.g. print). Here's a minimal example:
https://cloud.haddock.cc/s/3792TsJqoPnRetK

[eyllanesc]

@lumbo7332 I do not know if it is an oversight but anyway your code has 2 errors.

1. You never start the QThread.
2. You must use self.func(*self.args, **self.kwargs).

from contextlib import redirect_stdout
from io import StringIO

from PyQt5.QtWidgets import QTextEdit
from PyQt5.QtCore import QObject, QThread, pyqtSignal


class EmbeddedTerminal(QTextEdit):
    def __init__(self, parent):
        super(EmbeddedTerminal, self).__init__(parent)

    def run_func(self, func, *args, **kwargs):
        self.thread = QThread()
        self.worker = TerminalWorker(func, args, kwargs)
        self.worker.moveToThread(self.thread)
        self.thread.started.connect(self.worker.run)
        self.worker.progress.connect(self.update_terminal)
        self.thread.start()

    def update_terminal(self, text):
        self.setText(text)


class TerminalWorker(QObject):
    finished = pyqtSignal()
    progress = pyqtSignal(str)

    def __init__(self, func, args, kwargs):
        QObject.__init__(self)
        self.func = func
        self.args = args
        self.kwargs = kwargs

    def run(self):
        with redirect_stdout(StringIO()) as f:
            self.func(*self.args, **self.kwargs)
        output = f.getvalue()
        self.progress.emit(output)

[lumbo7332]

@eyllanesc Thank you. That helps with print working. But the input prompt still isn't showing up.

[eyllanesc]

@lumbo7332 What is the purpose of redirect_stdout? That all the printing in the console is shown in the QTextEdit, because that is what happens. input("test") prints "test" in stdout and then waits for the input, because now stdout is redirected to QTextEdit and not to the console.

Do you want the "test" to be printed in the console and in the QTextEdit at the same time?

[lumbo7332]

@eyllanesc I was trying to make it so the prompt gets printed in the QTextEdit, I can type input in the QTextEdit, and that input() will get that.

[eyllanesc]

@lumbo7332
No, it doesn't work like that. in input the message is printed in sys.stdout and the information is obtained from sys.stdin. What you write to QTextEdit will not write to sys.stdin. A possible solution would be that you detect when the user writes in the QTextEdit and that information write in sys.stdin.

You could also take inspiration from my answers:

• https://stackoverflow.com/questions/62349170/pyqt-terminal-emulator/62353195#62353195
• https://stackoverflow.com/questions/62479231/pyqt5-alternative-to-qtermwidget

[lumbo7332]

This post is deleted!

[lumbo7332]

This post is deleted!

[lumbo7332]

@eyllanesc I currently just want it to set the text of QTextEdit to sys.stdout, I can handle the input later. I'm really not sure why this isn't capturing the output , I have it setup to emit the output, but the QTextEdit isn't changing.

class TerminalWorker(QObject):
    finished = pyqtSignal()
    outputChanged = pyqtSignal(str)

    def __init__(self, func, args, kwargs):
        QObject.__init__(self)
        self.func = func
        self.args = args
        self.kwargs = kwargs

    def run(self):
        with redirect_stdout(StringIO()) as f:
            self.func(*self.args, **self.kwargs)
            print(f)
        self.outputChanged.emit(f.getvalue())

Minimal example: https://github.com/lumbo7332/qt-terminal