ODK Collect: create a mobile user authentication QR Code in Python

odk_qrcode.py

import base64
import json
import qrcode
import qrcode.image.svg as qrsvg
import zlib

def make_odk_auth_qrcode(server_url, app_user_token, project_id):
    """
    Creates a QR Code containing base server settings to connect to ODK.

    :param server_url: the URL to the ODK Central server
    :param app_user_token: the token of the mobile user
    :param project_id: the ID of the project for which the mobile user has rights.
    """
    endpoint_url = f'{server_url}/v1/key/{app_user_token}/projects/{project_id}'

    # Create ODK settings, parse them to JSON, compress them and encode them in b64
    odk_settings = {
        'general': {
            'server_url': f'{endpoint_url}',
        },
        'admin': {},
    }
    json_settings = json.dumps(odk_settings)
    bytes_settings = zlib.compress(json_settings.encode('UTF-8'))
    encoded_settings = base64.b64encode(bytes_settings)

    # Generate the QR Code
    qr = qrcode.make(encoded_settings)

    # Save the resulting QR Code
    # See this StackOverflow post if you wish to keep the resulting file in memory:
    # https://stackoverflow.com/questions/46593477/convert-pil-image-object-to-file-object/51553992
    qr.save('qrcode.jpg', 'JPEG')
    
if __name__ == '__main__':
    # Sample usage (resulting 'qrcode.jpg' file can be scanned by ODK Collect)
    # Note: you'll need python-qrcode installed (see instructions here: https://pypi.org/project/qrcode/)
    make_odk_auth_qrcode(
        'https://odk.example.com',
        'HRpcpt0OQ1tFEjfj3zZltFgnjeIYgnuTMXyTi7ZWaw4c!V$c6depxeJW4jU3j4mX',
        11,
    )