Callback function not updating values (Rospy)

edit

So it turns out that I was not using rospy.spin() and so ROS was not reading in data from the topics as they come in. I solved it by making my BSC class made up of only the __init__ and the callbacks and using the member variables I need in the __main__ function

class BSCFun:

    def __init__(self):
        # ROS Publishers
        self.pub = rospy.Publisher('/mobile_base/commands/velocity', Twist, queue_size=100);

        # ROS Subscribers
        self.odomSub = rospy.Subscriber('/odom', Odometry, self.odomCallback);
        self.goalSub = rospy.Subscriber('/move_base/current_goal', PoseStamped, self.goalCallback)
        self.velSub = rospy.Subscriber('/cmd_vel_mux/input/navi', Twist, self.optCmdCallback)
        self.teleSub = rospy.Subscriber('/cmd_vel_mux/input/teleop', Twist, self.userCmdCallback);
        self.rate = rospy.Rate(5);
        rospy.spin();    # Added this line

        # Removed BSCFun1()
    def publishMsg(self, msg):
        self.pub.Publish(msg);

    def userCmdCallback(self, msg):
        self.xVelUser= msg.linear.x;
        self.wzVelUser = msg.angular.z; 

    def optCmdCallback(self, msg):
        self.xVel = msg.linear.x;
        self.wzVel = msg.angular.z;
        rospy.loginfo("Updating Opt. Cmd.");

if __name__ == '__main__':
    # Init Node
    rospy.init_node('BSCFun', anonymous=True, log_level=rospy.DEBUG);
    bsc = BSCFun();
    # Stuck in 'spin'
    vMsg = Twist();
    try:
        # Code never actually reaches here...
        while not rospy.is_shutdown():
            # Blend velocity
            alpha = 0.5;
            newHeading = bsc.wzVel * (alpha - bsc.wzVelUser);
            vMsg.angular.z = newHeading;
            # Publish velocity
            bsc.publishMsg(vMsg);
    except rospy.ROSInterruptException:
        pass

My new problem is that ROS stays in its 'spin' state when the BSCFun class object is created and does not move on to the while loop in the main function. I would like to take the data from the subscribers callbacks and use it to 'blend' the velocity commands coming in (as seen in the while loop) but that is not working. I will post this as a new question but any suggestions would be appreciated.