You always need to generate your links and URLs. Hardcoded ones are a really bad habit. Coming from a Symfony environment, I’m familiar with $router->generate('my-route') but how does it work in PrestaShop? It turns out there are 2 ways depending on either you’re generating a frontend or a backend link.
Generate a Frontend URL
Generate a Backend URL
// Generic
$this->context->link->getAdminLink('AdminControllerHere')
$this->context->link->getAdminLink($this->controller_name) // from an AdminController
// Objects
// link to view a Customer
$this->context->link->getAdminLink('AdminCustomers')."&viewcustomer&id_customer=$id_customer";
// link to update a Category
$this->context->link->getAdminLink('AdminCategories')."&updatecategory&id_category=$id_category";
// link to update an Employee
$this->context->link->getAdminLink('AdminEmployees')."&updateemployee&id_employee=$id_employee";
// Modules
// go to a module config page
$this->context->link->getAdminLink('AdminModules')."&configure=module_name&module_name=module_name"
// go to a module config page, from the module itself
$this->context->link->getAdminLink('AdminModules')."&configure={$this->name}&module_name={$this->name}"