__init__.py

@login_view.route( "/totp_help" )
def totp_help():
    """
        Serve the help page for the TOTP.
    """
    current_app.logger.info( "Serving the TOTP help page" )
    return utils.template.my_render_template( "login/totp_help.html" )

################################################################################
#    QR Code generation

def renew_secret():
    """
        Request a new TOTP secret.
    """
    current_app.logger.info( "Generate new secret" )
    
    secret = pyotp.random_base32( 40 )
    session[ "secret" ] = secret
    
    return secret

def get_secret():
    """
        Retrieve the current secret.
    """
    current_app.logger.info( "Request secret for user '{}'".format( session[ "username" ] ) )
    
    secret = session.get( "secret", None )
    if secret == None:
        secret = renew_secret()
    
    return secret

@login_view.route( "/set_secret" )
def set_secret():
    """
        Set the new secret value for the TOTP in the database.
    """
    current_app.logger.info( "Storing new secret for user '{}'".format( session[ "username" ] ) )
    
    try:
        config.db.query( "UPDATE users SET totp = %s WHERE username = %s", ( session[ "secret" ], session[ "username" ], ) )
        config.db.commit()
        
        return jsonify( {
            "error": False
        } )
    
    except:
        return jsonify( {
            "error": True
        } )

@login_view.route( "/secret" )
def request_secret():
    """
        Serve the current secret as JSON.
    """
    current_app.logger.info( "Request the secret for user '{}'".format( session[ "username" ] ) )
    
    get_secret()
    
    return jsonify( {
        "error": False,
        "secret": session[ "secret" ]
    } )

@login_view.route( "/new_secret" )
def request_renew_secret():
    """
        Serve current secret.
    """
    current_app.logger.info( "Renew TOTP secret for user '{}'".format( session[ "username" ] ) )
    
    renew_secret()
    
    return jsonify( {
        "error": False,
        "secret": session[ "secret" ]
    } )

@login_view.route( "/user/config/totp_qrcode.png" )
def user_totp_qrcode():
    """
        Generate the TOTP PNG QRcode image ready to scan.
    """
    current_app.logger.info( "Generate the TOTP QRcode" )
    
    if "username" in session:
        qrcode_value = "otpauth://totp/ICNML%20{}?secret={}&issuer=ICNML".format( session[ "username" ], get_secret() )
    else:
        qrcode_value = "otpauth://totp/ICNML?secret={}&issuer=ICNML".format( get_secret() )
    
    current_app.logger.debug( "Value: {}".format( qrcode_value ) )
    
    img = qrcode.make( qrcode_value )
    
    temp = StringIO()
    img.save( temp, format = "png" )
    temp.seek( 0 )
    
    return send_file( temp, mimetype = "image/png" )
    
@login_view.route( "/user/config/example_totp_qrcode.png" )
def user_totp_qrcode_example():
    qrcode_value = "otpauth://totp/ICNML%20{}?secret={}&issuer=ICNML".format( "user_name", "secretsecretsecretsecret" )
    
    img = qrcode.make( qrcode_value )
    
    temp = StringIO()
    img.save( temp, format = "png" )
    temp.seek( 0 )
    
    return send_file( temp, mimetype = "image/png" )
@login_view.route( "/user/config/totp" )
@utils.decorator.login_required
def user_totp_config():
    """
        Serve the TOTP configuration page.
    """
    current_app.logger.info( "Serve the TOTP config page" )
    
    return utils.template.my_render_template( 
        "login/users/totp.html",
        secret = get_secret()
    )