navdiana / flexx

Write desktop and web apps in pure Python

Flexx

Introduction

Flexx is a pure Python toolkit for creating graphical user interfaces (GUI's), that uses web technology for its rendering. Apps are written purely in Python; Flexx' transpiler generates the necessary JavaScript on the fly.

You can use Flexx to create (cross platform) desktop applications, web applications, and (if designed well) export an app to a standalone HTML document. It also works in the Jupyter notebook.

The docs are on Readthedocs. the code is on Github. Flexx is currently in alpha status; any part of the public API may change without notice. Feedback is welcome.

Flexx has a modular design, consisting of a few subpackages, which can also be used by themselves:

• flexx.ui - the widgets
• flexx.app - the event loop and server
• flexx.event - properties and events
• flexx.pyscript - Python to JavaScript transpiler
• flexx.webruntime - to launch a runtime
• flexx.util - utilities

Status

Early 2017 we were close to a new release and moving to beta-status. However, we found that in some real (bigger) applications written in Flexx, we were hitting certain boundaries. We believe that these boundaries prevent Flexx from being usable at a large scale.

We've since looked at what does boundaries are and how Flexx would need to change to be able to remove or move beyond these boundaries. This has culminated in a plan to refactor Flexx.

These changes are quite substantial. E.g. a central idea of the current Flexx is having objects that exist in both Python and JS and have properties that are settable from both ends. This will be no more. Instead, objects live/operate either in Python or JS, but objects in JS can still be referenced and influenced from Py.

Example

Click the image below for an interactive example:

There are two demo servers at http://flexx1.zoof.io (an instance in Amazon's cloud) and http://flexx2.zoof.io/ (a Raspberry pi). Either might not always be on.

Motivation

The primary motivation for Flexx is the undeniable fact that the web (i.e. browser technology) has become an increasingly popular method for delivering applications to users, also for (interactive) scientific content.

The purpose of Flexx is to provide a single application framework to create desktop applications, web apps, and (hopefully soon) mobile apps. By making use of browser technology, the library itself can be relatively small and pure Python, making it widely available and easy to use.

Installation

Flexx requires Python 2.7 or Python 3.2+ and also works on pypy. Further, it needs the tornado library (pure Python). For running desktop apps, it is recommended to have Firefox installed.

To install use any of:

• conda install flexx -c conda-forge
• pip install flexx
• Clone the repo and add it to your PYTHONPATH, or python setup.py install.

License

Flexx makes use of the liberal 2-clause BSD license. See LICENSE for details.