async_gui 0.1.0 (beta)

Easy threading and multiprocessing for GUI applications

async_gui

async_gui is a library aimed to make use of threads in GUI applications simpler. It's inspired by PyCon talk Using futures for async GUI programming in Python 3.3 and tornado @gen.engine implementation.

Most of GUI toolkits don't allow you to access graphical elements from non-GUI thread. Python 3.2+ has nice new feature concurrent.futures, but we can't just wait for result from future and callbacks are not very handy.

Combination of Coroutines via Enhanced Generators (PEP-342) and futures creates a rich and easy to use asynchronous programming model which can be used for creating highly responsive GUI applications.

Example

Demo of button click handler:

.. code-block:: python

    @engine.async
    def on_button_click(self, *args):
        self.status_label.setText("Downloading image...")
        # Run single task in separate thread
        image_data = yield Task(self.load_url,
                                "http://www.google.com/images/srpr/logo4w.png")
        pixmap = QtGui.QPixmap.fromImage(QtGui.QImage.fromData(image_data))
        self.image_label.setPixmap(pixmap)
        self.status_label.setText("Downloading pages...")
        urls = ['http://www.google.com',
                'http://www.yandex.ru',
                'http://www.python.org']
        # Run multiple task simultaneously in thread pool
        pages = yield [Task(self.load_url, url) for url in urls]
        self.status_label.setText("Done")
        avg_size = sum(map(len, pages)) / len(pages)
        self.result_label.setText("Average page size: %s" % avg_size)

Tasks yielded from on_button_click() executed in thread pool, but GUI updates done in the GUI thread. For CPU-bound applications there is also ability to run tasks in pool of processes.

See full example in examples directory.

Features

• Python 2.7+ (futures required), Python 3+ support
• PyQt4/PySide, Tk, Wx, Gtk GUI toolkits support. Easy to add another
• Can execute tasks in Thread, Process, Greenlet (gevent required)
• Possibility to run multiple tasks at the same time
• Straightforward exception handling
• Full test coverage

Installation

Using pip:

$ pip install async_gui

Or download, unpack and:

$ python setup.py install

To run tests use:

$ python setup.py test

Links

• Documentation at readthedocs.org
• Source code and issue tracking at GitHub.

History