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Using the Context Object

What is the Context object?

The Context is a registry for PHP variables that were previously accessed as globals. It aims to standardize the way these variables are accessed, and to make the code more robust by getting rid of global vars.

What is stored by the Context?

These objects are always accessible through the context:

  • Language. Set with the customer or employee language.
  • Country. Default country.
  • Currency. Set with the customer currency or the shop's default currency.
  • Shop. Current shop.
  • Cookie. Cookie instance.
  • Link. Link instance.
  • Smarty. Smarty instance.

These objects are only accessible for the customer Context:

  • Customer. Existing customer retrieved from the cookie or default customer.
  • Cart. Current cart.
  • Controller. Current controller instance.

These objects are only accessible for the administrator Context:

  • Employee. Current employee.

How to access the Context?

From inside a Controller subclass, an AdminTab subclass or a Module subclass, the Context should be called with this shortcut: $this->context.

From anywhere else, you can get the Context instance by calling Context::getContext().

How is the Context initialized?

The context is initialized with data coming from the cookie or from the database. For example, to create the Language object, the context looks for an id_lang value in the cookie. If it doesn't find one, it will retrieve the default language id from the database.

How to use the Context?

Whenever you would have accessed the cookie to retrieve a variable, or used a global statement, you will probably want to access the Context instead.

A few common replacements:

  • Static shortcuts in FrontController subclasses are deprecated:
    $id_cart = self::cart->id;
    
    ...is to be replaced with...
    $id_cart = $this->context->cart->id;
    
  • Do not recreate an object that already exists:
    $language = new Language($cookie->id_lang);
    
    $iso_code = $language->iso_code;
    
    ...is to be replaced with...
    $iso_code = $this->context->language->iso_code;
    

More examples of Context use:

Old way

New way

$cookie->id_lang;

$this->context->language->id;

if ($cookie->isLogged())

if ($this->context->customer->isLogged())

if ($cookie->isLoggedBack())

if ($this->context->employee->isLoggedBack();

$cart->getProducts();

$this->context->cart->getProducts();

$language = new Language($cookie->id_lang);
$language->iso_code;

$this->context->language->iso_code;

new Currency($cookie->id_lang);

$this->context->currency;

$defaultCountry->id_zone;

$this->context->country->id_zone;

new Link();

$this->context->link;

$smarty->assign(...);

$this->context->smarty->assign(...);

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