Friendly URL problem in front module - Prestashop - prestashop

Question

I am building a front module for a website that is using 301 Moved Permanently option in SEO and URLs configuration.
Wesbite uses Prestashop 1.6.1.9.
In module, I am defining the route like this:
public static $ModuleRoutes = array(
'module-aacategories-viewmapping-mapping' => array(
'controller' => 'viewmapping',
'rule' => 'mappings{/:tree}',
'keywords' => array(
'tree' => array('regexp' => '[/_a-zA-Z0-9-\pL]*', 'param' => 'tree'),
),
'params' => array(
'fc' => 'module',
'module' => 'aacategories',
)
)
);
In browser address bar, when I enter:
site.local/en/mappings/test-map/first-test
I get:
Please use the following URL instead:
site.local/en/index.php?controller=viewmapping&tree=test-map%2Ffirst-test&module=aacategories
This latter link gives 404. However, when I append &fc=module to the url, it goes to desired page.
The problems:
1- How to force Prestashop routing to append &fc=module at the end?
2- How to keep the friendly url in address bar and not be redirected?
Note: When I change configuration in SEO and URLs to no redirection, then it works. But it is not the configuration needed in prod.
Your help is much appreciated. Thanks in advance.

Answer 1

The problem is you are setting public property $php_self in your module controller.
You need to remove the property so that core front controller does not do a canonical redirect.
The code that does this is in FrontController.php line 378.
if (!empty($this->page_name)) {
$page_name = $this->page_name;
} elseif (!empty($this->php_self)) {
$page_name = $this->php_self;
} elseif (Tools::getValue('fc') == 'module' && $module_name != '' && (Module::getInstanceByName($module_name) instanceof PaymentModule)) {
$page_name = 'module-payment-submit';
}
// #retrocompatibility Are we in a module ?
elseif (preg_match('#^'.preg_quote($this->context->shop->physical_uri, '#').'modules/([a-zA-Z0-9_-]+?)/(.*)$#', $_SERVER['REQUEST_URI'], $m)) {
$page_name = 'module-'.$m[1].'-'.str_replace(array('.php', '/'), array('', '-'), $m[2]);
} else {
$page_name = Dispatcher::getInstance()->getController();
$page_name = (preg_match('/^[0-9]/', $page_name) ? 'page_'.$page_name : $page_name);
}
And then does a canonical redirect if you set that property on line 401.
if (!empty($this->php_self) && !Tools::getValue('ajax')) {
$this->canonicalRedirection($this->context->link->getPageLink($this->php_self, $this->ssl, $this->context->language->id));
}