Geolocation plugin: enforce a certain currency?

-- url of the page with the problem -- : shop.smartgart.com/de/rauchwarnmelder/pr...rene-pope004001.html
-- HikaShop version -- : 2.6.3
-- Joomla version -- : 3.5.1
-- PHP version -- : 5.5.28
-- Browser(s) name and version -- : Chrome XXX
-- Error-message(debug-mod must be tuned on) -- : Google warning for "wrong" currency (Geolocation plugin)

HikaShop + geolocation plugin + default currency
www.hikashop.com/support/documentation/7...n.html#configuration

Question: Possible to link to a page and enforce a specific currency, e. g. EUR?

Not really a bug but a hidden feature question:
For Google Merchants/Shopping, I generate a tab-separated price feed file, e. g. for France:
www.smartgart.com/export/export-prices-google-fr.tsv
Prices are in Euro, and the links go deeply to the product page.

So when a French visitor to visit the page, the product value is displayed in EUR.
But for a Canadian or Indian visitor, the product value is displayed in CAD or INR.

This makes lots of sense, but for Google Shopping, I need to enforce that (independent of visitor location) the price is displayed in a certain currency, i. e. EUR for France. This is so that when a Google tester from non-France, non-Euro clicks, they do not see the "wrong" (their own) currency.

Is there a secret override switch like ?currency=EUR?

If not, I have to code that in, because Google has warned me.

Thanks Nicolas. Writing a system plugin makes the most sense, however I don't feel proficient enough at the moment.

I tried to quickly hack a function into the components/com_hikashop/controllers/currency.php (snippet below),
however I do not understand how to register it with the lifecycle of the runtime environment.

The idea is that I pass a parameter key/value like &cur=2, and the currency gets set to that currency_id.
Howevere, update() is only called for the update POST of the currency module,
whilst my initial load is the GET from a Google Shopping shopping page.

I checked the .xml's for configuring that but cannot figure it out yet.

best regards

Klaus

	function get() {
		$currency=JRequest::getInt('cur',0,'get'); // override for/from Google Shopping
		// or: $currency = $_GET['cur'];
		if(strlen($currency) > 3) $cur = 1; // simple filtering against injections
		if(!empty($currency)){
			$app = JFactory::getApplication();
			$app->setUserState( HIKASHOP_COMPONENT.'.currency_id', $currency );
		}
	}