Table of contents

Using the Context Object

What is the Context object?

The Context is a technical feature introduced with version 1.5 of PrestaShop. Its two goals are:

• preventing developers from using global variables.
• enabling them to change the context of some methods.

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.
It is a light implementation of the Registry design pattern: it is a class that stores the main PrestaShop information, such as the current cookie, the customer, the employee, the cart, Smarty, etc.

Before version 1.5, you had to rely on the cookie in order to access this data:

$cookie->id_lang;

Now that the Context is available, the same data can be accessed more cleanly:

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

What is stored by the Context?

...

A few common replacements:

• Static shortcuts in FrontControllersubclasses are deprecated:

  Code Block
  language php title PrestaShop 1.4 code
  $id_cart = self::cart->id;

  ...is to be replaced with...

  Code Block
  language php title PrestaShop 1.5 code
  $id_cart = $this->context->cart->id;

• Do not recreate an object that already exists:

  Code Block
  language php title PrestaShop 1.4 code
  $language = new Language($cookie->id_lang); $iso_code = $language->iso_code;

  ...is to be replaced with...

  Code Block
  language php title PrestaShop 1.5 code
  $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(...);

Using the Context in a PrestaShop 1.4 module

Modules written for PrestaShop 1.5, and which therefore rely on the Context object, can be made to gracefully degrade its Context use in order to work in PrestaShop 1.4.

Add this method to the module's main class:

// Retrocompatibility 1.4/1.5
private function initContext()
{
  if (class_exists('Context'))
    $this->context = Context::getContext();
  else
  {
    global $smarty, $cookie;
    $this->context = new StdClass();
    $this->context->smarty = $smarty;
    $this->context->cookie = $cookie;
  }
}

Then, add this line in the module's constructor method:

// Retrocompatibility
$this->initContext();

Additionally, when rewriting you v1.5 module in work to work in v1.4, you should use the older hook names, such as displayProductTab or displayProductTabContent. These two example hooks are respectively registered using the productTab and productTabContent calls, which are compatible for both v1.4 and v1.5, but will not work in the next major version.