Creating a carrier module

Principles

A carrier module is a regular PrestaShop module, except that it extends the CarrierModule class instead of the Module class:

class MyOwnCarrier extends CarrierModule

It can be attached to the following hooks:

• extraCarrier: to display the shipping price depending on the ranges that were set in the back office.

A carrier module must use the following methods:

• getOrderShippingCost(): to compute the shipping price depending on the ranges that were set in the back office.
• getOrderShippingCostExternal(): to compute the shipping price without using the ranges.

The getOrderShippingCost() method can also be used to compute the shipping price depending on the products:

$shipping_cost = $module->getPackageShippingCost($cart, $shipping_cost, $products);

Installing and uninstalling the module

The module must handle:

• Its own installation, and the installation of one or more carriers.
• Its own uninstallation, and the "deletion" of one or more of its carriers.

Note about deletion:

• Deleting a carrier simply means its deactivation (deleted=true).
• The module must keep the link between an old order and a carrier that is not available anymore.
• Careful: the default carrier must exist and be enabled.

Controlling the change of the carrier's ID

To control the change of the carrier's ID (id_carrier), the module must use the updateCarrier hook.

For instance:

public function hookUpdateCarrier($params)
{
  $id_carrier_old = (int)($params['id_carrier']);
  $id_carrier_new = (int)($params['carrier']->id;
  if ($id_carrier_old == (int)(Configuration::get('MYCARRIER_CARRIER_ID')))
    Configuration::updateValue('MYCARRIER_CARRIER_ID', $id_carrier_new);
}

Computing the shipping price

To compute the shipping price, PrestaShop needs to call the module's getOrderShippingCost() or getOrderShippingCostExternal().

The returned value must of the float type.

For instance:

public function getOrderShippingCost($params, $shipping_cost)
{
  if ($this->id_carrier == (int)(Configuration::get('MYCARRIER_CARRIER_ID'))
      && Configuration::get('MYCARRIER_OVERCOST') > 1)
    return (float)(Configuration::get('MYCARRIER1_OVERCOST'));
  return false; // carrier is not known
}