Add Canonical tag's to Prestashop

FrontController.php

<?php
// Feel free to copy IF you create a href link that point to http://www.dyrefoder.dk from your google indexed website
// Thank you
// Michael Hjulskov
// www.dyrefoder.dk

class FrontController extends FrontControllerCore
{
	public function init()
	{
		parent::init();
		$this->context->smarty->assign('canonical_url', $this->getCanonicalUrl());
	}

	protected function getCanonicalUrl()
	{
		if (Tools::getValue('ajax'))
			return false;
		
		$base_dir = $this->context->smarty->getTemplateVars('base_dir');
		$page_name = $this->context->smarty->getTemplateVars('page_name');
		
		if ($page_name == 'index')
			return $base_dir;

		if ($page_name == 'search' && Tools::getValue('tag'))
			return $this->context->link->getPageLink($page_name, true, null, 'tag='.Tools::getValue('tag'));
		
		if ($page_name == 'search' && Tools::getValue('search_query'))
			return $base_dir; // TODO - is this the right thing to do? To just set base url as canonical url - or should it be indexed?
			//return $this->context->link->getPageLink($page_name, true, null, 'search_query='.Tools::getValue('search_query'));
		
		// List Pages - without any id (relevant might be: n,p,orderby,orderway)
		$non_id_list_pages = array('manufacturers','suppliers','best-sales','new-products','prices-drop','all-products');
		if (in_array($page_name, $non_id_list_pages)) 
			return $this->context->link->getPageLink($page_name, true, null);
			// TODO fix something with the params: n,p,orderby,orderway
			//return $this->context->link->getPageLink($page_name, true, null, ((Tools::getValue('p'))?'p='.Tools::getValue('p'):''));
			//return $this->context->link->getPageLink($page_name, true, null, ((Tools::getValue('n'))?'n='.Tools::getValue('n'):''));
			//return $this->context->link->getPageLink($page_name, true, null, ((Tools::getValue('orderby'))?'orderby='.Tools::getValue('orderby'):''));
			//return $this->context->link->getPageLink($page_name, true, null, ((Tools::getValue('orderway'))?'orderway='.Tools::getValue('orderway'):''));

		// List Pages - with id parameter (relevant might be: )
		$id_detail_pages = array('category','manufacturer','supplier','product','blog','cms');
		if (in_array($page_name, $id_detail_pages) && Tools::getValue('id_'.$page_name)){
			if ($page_name == 'product')
				return $this->context->link->getProductLink(Tools::getValue('id_'.$page_name));
			if ($page_name == 'manufacturer')
				return $this->context->link->getManufacturerLink(Tools::getValue('id_'.$page_name));
			if ($page_name == 'category')
				return $this->context->link->getCategoryLink(Tools::getValue('id_'.$page_name));
			if ($page_name == 'cms')
				return $this->context->link->getCmsLink(Tools::getValue('id_'.$page_name));
			if ($page_name == 'supplier')
				return $this->context->link->getSupplierLink(Tools::getValue('id_'.$page_name));
			return $this->context->link->getPageLink($page_name, true, null, 'id_'.$page_name.'='.Tools::getValue('id_'.$page_name));
		}

		// Single information pages - without any id (relevant might be: back)
		$non_id_single_pages = array(
			'contactform','contact','authentication','order','cart','discount','my-account','password',
			'order-detail','order-opc','order-slip','history','address','addresses','identity','remindme',
			'stores','sitemap'
		);
		if (in_array($page_name, $non_id_single_pages))
			return $this->context->link->getPageLink($page_name, true, null);

		// AS4 seo pages - quick fix - TODO improve
		if (Tools::getValue('id_seo')) //Tools::getValue('id_search')
			return $base_dir . substr(strtok($_SERVER["REQUEST_URI"],'?'), 1);

		// other pages - quick fix
		// TODO this is meant as temp solution -should be improved
		return $base_dir . substr(strtok($_SERVER["REQUEST_URI"],'?'), 1);

		// return false;
		
		/* old stuff i might need later
		if (strpos($_SERVER['REQUEST_URI'], 'p=') === false){
		return $base_dir . preg_replace('/\?(.*)/', '', preg_replace('/\/(.*)/', '', substr($_SERVER['REQUEST_URI'], 1)));
		$url = $server_name . strtok($_SERVER["REQUEST_URI"],'?').'?p='.Tools::getValue('p');
		*/
	}
}

header.tpl

Feel free to copy IF you create a href link that point to http://www.dyrefoder.dk from your google indexed website
Thank you
Michael Hjulskov
www.dyrefoder.dk

insert this in your header.tpl file the right place:
{if isset($canonical_url) && $canonical_url}<link rel="canonical" href="{$canonical_url}" />{/if}

and override your FrontController.php

tada - you should have canonical tags :)

you should use base_dir_ssl to take into account https

Feel free to copy IF you create a href link that point to http://www.dyrefoder.dk from your google indexed website
Thank you
Michael Hjulskov
www.dyrefoder.dk