Electron-Flask Bootstrap Template

Dependencies

Python 3.9	NodeJS 16.x

Installation

Clone the repository git clone ...
Install Python dependencies python -m pip install -r requirements.txt
Install node modules npm install

Running the App

Start app

Windows: .\node_modules\.bin\electron .
Mac OS/Linux: ./node_modules/.bin/electron .

Start app with globally installed electron

electron .

Run the app through your web browser

Start Flask server manually: python web_app/run_app.py

Bundling

Packaging is done in two steps:

A standalone Python executable containing the Flask backend is generated using PyInstaller
The Python executable and the electron application (electron.js) are bundled using electron-builder

NOTE: The Python executable is generated in the "one-file-mode"; All dependencies are wrapped in a single executable. When executed, the program is decompressed to a temporary directory and run in a second process from there. This has to be considered in the life-cycle management of the electron app. See killPythonSubprocesses of electron.js.

Package the app for the host platform

npm run package (output binaries will be stored in /dist)

Cross-Platform packaging

Not yet supported (due to lacking cross-compilation support of PyInstaller)

Why Flask?

Using a Flask webserver for interprocess communication (ICP) comes in handy to bundle an existing Flask-based service into a desktop application. The endpoints don't have to be changed.
For other applications there are more efficient alternatives to using Flask/HTTP for ICP, e.g. zerorpc.

Encountered Issues

asar is read-only, .pyc files cannot be created
When bundling the standalone Python executable in an .asar, a random filename is generated. This makes life-cycle management of the backend service difficult (see also section Bundling).

Feature Backlog

Bundling Resources with the Python Executable

use --add-data to bundle resources with the python executables (use sys._MEIPASS to resolve paths)
see python-eel/Eel#57

def resource_path(relative_path):
    """ Get absolute path to resource, works for dev and for PyInstaller """
    if hasattr(sys, '_MEIPASS'):
        return os.path.join(sys._MEIPASS, relative_path)
    return os.path.join(os.path.abspath("."), relative_path)

Cross-Compilation through Docker

create a Docker image to allow building for Linux on Windows

ASAR Bundling

When bundling the electron app in an .asar, the path to the python executable (which is copied to the resource folder) is not resolved properly

matbloch/electron-flask