PHP OOP :: passing session key between classes

Question

I am trying to develop the most suitable design for passing session key between classes in PHP 5.3.

The session key is retrieved from a third-party API, and my application makes various API calls that require this session key to be passed.

I created classes to hold related API calls. For example, the basket directory contains methods that, when called, will send an API request to return data from calls such as API_GetCart (), API_AddItem (), etc.

I store the session key in a single cookie (the only cookie that is ever required) and I need to make the value of this cookie available to almost all of my classes. I cannot use a database or $ _SESSION to store session data. A third-party API is looking for session management for things like basket contents, etc.

When the user reaches my application for the first time, there will be no cookie value, so I will need to both assign a new session key to the new cookie and transfer this value (not yet available as a cookie, we are still processing one and same HTTP request) to other classes.

One of my ideas was to create a Session class like this and put the code grab / check code in the constructor.

class Session { public $sk; function __construct() { //code to check if user has sessionkey (sk) in cookie //if not, grab new sessionkey from 3rd party API and assign to new cookie // $sk = 'abcde12345'; //example $sk value } } 

Then, on all the browsing pages, I would instantiate a new Session instance and then pass this object to each class that requires it (almost all), either as an argument to the class constructor, or as an argument to a method.

orderSummary.php

 $s = new Session; //$s currently would only hold one variable, $sk = "abcde12345" //but in the future may hold more info or perform more work // what is best approach to making the sessionkey // available to all classes? arg to constructor or method... or neither :) $basket = new Basket; $baskSumm = $basket->getBasketSummary(); $billing = new Billing; $billSumm = $billing->getBillingSummary(); $delivery = new Delivery; $delSumm = $delivery->getDeliverySummary(); //code to render as HTML the customer basket details //as well as their billing and delivery details 

Does the Session class (which really only contains one value) create a better idea? Given that he might need more values ​​and perform a larger check, he felt "right", making him a class. As for passing this value to different classes, it would be better to pass the Session object to their constructor, for example.

 $se = new Session; $basket = new Basket($se); $baskSumm = $basket->getBasketSummary(); 

I am new to OOP, so some recommendations will be greatly appreciated.

Answer 1

You can use the Factory pattern. Basket, billing, and delivery objects must be created by a third-party wrapper class of API services:

 $svc = new The3rdPartyServiceApiWrapper(); $svc->init(); // connect, get session etc. if ($svc->fail()) die("halp! error here!"); $basket = $svc->createBasket(); $baskSumm = $basket->getBasketSummary(); $billing = $svc->createBilling(); $billSumm = $billing->getBillingSummary(); $delivery = $svc->createDelivery(); $delSumm = $delivery->getDeliverySummary(); 

The best way to connect the Basket, Billing, and Delivery classes with the API is to store a reference to the API class, then they can call any method, not just getSession ().

Another advantage is that if you have an identified object, for example. user, then the wrapper class can provide you with no double objects in the scene.

If the main program creates users, there must be different objects with the same user, which is wrong:

 $user1 = new User("fred12"); $user2 = new User("fred12"); 

VS, if the API shell creates them, the shell class must store the "cache" of users and return with the same User object for the same request:

 $user1 = $svc->createUser("fred12"); $user2 = $svc->createUser("fred12"); // $user2 will be the same object 

(Maybe this is not a good example, if the program creates twice the same user, this means that the program has a serious design flaw.)

UPDATE: svc class explanation

The3rdPartyServiceApiWrapper should look like this:

  function getSessionId() { return $this->sessionId; // initialized by constructor } // getSessionId() function createBasket() { $basket = new Basket($this); return $basket; } // createBasket() 

Basket:

  function Basket($s) { // constructor of Basket class $this->svc = $s; //... the rest part of constructor } // Basket() constructor function doSomethingUseful() { // if you wanna use the session: $sess = $this->svc->getSessionId(); echo("doing useful with session $session"); // you may access other api functions, I don't know what functions they provide $this->svc->closeSession(); } // doSomethingUseful()