USSD（状态机）应用算法

Question

I have created a USSD application in PHP, Since USSD requests are unique ( new request for each selection ) I need a way to track them , Track in the sence i need a way to store the flow of the application, In my USSD app there are Static menus as well as Dynamic menus ( Retrieved from the Database ) , My problem is , I have created the app with lots of if, else and switch statements, And It's really difficult to update the menu items. So can anyone suggest me a good algorithm to create this USSD app? I mean a efficient way to tackle the problem, I need a way where I could be able to add and remove menus according the clients request, When I do that , my code shouldn't break. Can anyone help me on this?

-Thanks & Regards

PS: I have read this and this and it doesn't actually answer my question.

Answer 1

The best method working with USSD is making each command a separate class. This way you can work , debug and maintain a large USSD application

Example

$ussd = new USSDMessage(); // USSD Class 

$main = new Command("menu"); // Starting Command 

// Register multiple command 
$main->register(new Command("help"));
$main->register(new Command("account"));
$main->register(new Command("transfer"));
$main->register( new Recharge("reacharge"));

$main->run($ussd); // Run Request 

Basic Class Structure

// Class To receve message from USSD
class USSDMessage {
    function next();
    function saveSession();
}

// Basic Command  Class 
class Command {
    private $name;
    private $cmd = array();

    function __construct($name) {
        $this->name = $name;
    }

    function register(Command $menu) {
        $this->cmd[$menu->getName] = $menu;
    }

    function run(USSDMessage $ussd) {
        $key = $ussd->next(); // get next inpur from ussd

        if (isset($this->cmd[$key])){
            $ussd->run($ussd);
        }
    }
}

// Recharge Command Example 
class Recharge extends Command {

    function run(USSDMessage $ussd) {
        $key = $ussd->next();

        switch ($key){
            case "1":
                // Proccess card recharge
                // Do Somthing 
                $ussd->saveSession(); // End Session 
                break;
            case "2":
                // Process direct deposit
                // Do Somthing
                $ussd->saveSession(); // End Session
                break;
            default:
                // Format Not supported
                // Do Somthing
                $ussd->saveSession(); // End Session
                break;
        }
    }
}