How to install openconnect-sso on Ubuntu 21.04

I would like to install openconnect-ssh. The install instructions from the project seem complex, I'm not sure what pipx is.

How do I install openconnect-sso on Ubuntu without using pipx and using native Ubuntu qt libraries?

I tried to install it using pip, but I got the following errors:

Traceback (most recent call last):
  File "/home/merlijn/.local/bin/openconnect-sso", line 5, in <module>
    from openconnect_sso.cli import main
  File "/home/merlijn/.local/lib/python3.9/site-packages/openconnect_sso/cli.py", line 10, in <module>
    from openconnect_sso import app, config, __version__
  File "/home/merlijn/.local/lib/python3.9/site-packages/openconnect_sso/app.py", line 16, in <module>
    from openconnect_sso.authenticator import Authenticator, AuthResponseError
  File "/home/merlijn/.local/lib/python3.9/site-packages/openconnect_sso/authenticator.py", line 6, in <module>
    from openconnect_sso.saml_authenticator import authenticate_in_browser
  File "/home/merlijn/.local/lib/python3.9/site-packages/openconnect_sso/saml_authenticator.py", line 3, in <module>
    from openconnect_sso.browser import Browser
  File "/home/merlijn/.local/lib/python3.9/site-packages/openconnect_sso/browser/__init__.py", line 1, in <module>
    from .browser import Browser, DisplayMode, Terminated
  File "/home/merlijn/.local/lib/python3.9/site-packages/openconnect_sso/browser/browser.py", line 5, in <module>
    from . import webengine_process as web
  File "/home/merlijn/.local/lib/python3.9/site-packages/openconnect_sso/browser/webengine_process.py", line 12, in <module>
    from PyQt5.QtCore import QUrl, QTimer
ModuleNotFoundError: No module named 'PyQt5'

Traceback (most recent call last):
  File "/home/merlijn/.local/bin/openconnect-sso", line 5, in <module>
    from openconnect_sso.cli import main
  File "/home/merlijn/.local/lib/python3.9/site-packages/openconnect_sso/cli.py", line 10, in <module>
    from openconnect_sso import app, config, __version__
  File "/home/merlijn/.local/lib/python3.9/site-packages/openconnect_sso/app.py", line 16, in <module>
    from openconnect_sso.authenticator import Authenticator, AuthResponseError
  File "/home/merlijn/.local/lib/python3.9/site-packages/openconnect_sso/authenticator.py", line 6, in <module>
    from openconnect_sso.saml_authenticator import authenticate_in_browser
  File "/home/merlijn/.local/lib/python3.9/site-packages/openconnect_sso/saml_authenticator.py", line 3, in <module>
    from openconnect_sso.browser import Browser
  File "/home/merlijn/.local/lib/python3.9/site-packages/openconnect_sso/browser/__init__.py", line 1, in <module>
    from .browser import Browser, DisplayMode, Terminated
  File "/home/merlijn/.local/lib/python3.9/site-packages/openconnect_sso/browser/browser.py", line 5, in <module>
    from . import webengine_process as web
  File "/home/merlijn/.local/lib/python3.9/site-packages/openconnect_sso/browser/webengine_process.py", line 14, in <module>
    from PyQt5.QtWebEngineWidgets import QWebEngineView, QWebEngineScript, QWebEngineProfile
ModuleNotFoundError: No module named 'PyQt5.QtWebEngineWidgets'

Here is an issue I opened linking to my installation instructions: https://github.com/vlaci/openconnect-sso/issues/114 <-- (upvote this with a thumbs up sign on GitHub if you agree and want to get it attention)

...which are here: How to use "openconnect" (via the openconnect-sso wrapper) with SAML and Duo two-factor authentication via Okta Single-Sign-on (SSO) <-- see here for full instructions, details, and screenshots.

In short, do this to install openconnect and openconnect-sso on Linux Ubuntu:

sudo apt update
sudo apt install vpnc-scripts openconnect   # install openconnect
sudo apt install python3

python3 -m pip install --upgrade pip
python3 -m pip install openconnect-sso      # install openconnect-sso

# install openconnect-sso dependencies, including forcing a reinstall of PyQt5

# uninstall
python3 -m pip uninstall PyQt5
python3 -m pip uninstall PyQt5-sip
python3 -m pip uninstall PyQtWebEngine
python3 -m pip uninstall keyring

# reinstall
python3 -m pip install PyQt5
python3 -m pip install PyQt5-sip
python3 -m pip install PyQtWebEngine
python3 -m pip install keyring

python3 -m pip install cffi

# Check the version
# My output is: `openconnect-sso 0.7.3`
openconnect-sso --version

Usage (note: for how to find your server address and SAML group, see "How to find your VPN server address and SAML group" at the bottom of my answer here):

VPN_SERVER_ADDRESS="myvpn.whatever.com"   # example server address to connect to
VPN_SAML_GROUP="whatever-saml-whatever"   # example SAML group name
VPN_USER="[email protected]"      # example username
# or perhaps just this for the username:
# VPN_USER="my.username"

# connect via `openconnect-sso`
# The first time ever, you must specify everything
openconnect-sso --server "${VPN_SERVER_ADDRESS}/${VPN_SAML_GROUP}" --user "${VPN_USER}"
# Subsequent connection attempts can be done with just this, since apparently
# the server address, SAML group, and username are cached after the first usage
openconnect-sso

First, you need to install the Qt5 Python dependencies:

sudo apt install python3-pyqt5 python3-pyqt5.qtwebengine

Then you install openconnect-sso using pip

pip install openconnect-sso

Afterwards, you can easily run the app:

$ openconnect-sso -s vpn.example.com --browser-display-mode shown
[info     ] Authenticating to VPN endpoint [openconnect_sso.app] address=vpn.example.com name=
[info     ] Response received              [openconnect_sso.authenticator] id=main message=Please complete the authentication process in the AnyConnect Login window. title=Login
[info     ] Browser started                [webengine] startup_info=StartupInfo(url='https://vpn.example.com/...', credentials=None)
[info     ] Loading page                   [webengine] url=https://vpn.example.com/...
[info     ] Terminate requested.           [webengine] 
[info     ] Exiting browser                [webengine] 
[info     ] Browser exited                 [openconnect_sso.browser.browser] 
[info     ] Response received              [openconnect_sso.authenticator] id=success message=