Api.php

public static function addOffersMobile(&$catalog, $lang)
    {
        $offersModel = new Lmc_Core_Model_Offers_Model();

        foreach($catalog as $n => $val) {
            $catalog[$n]['offers'] = $offersModel->getOffersForProducts(array(array('ProductId' => $val['ProductId'])), array('Site' => $lang))->toArray();
        }
    }

    /**
     * Get all products for a given category id
     *
     * @param string $token the session token
     * @param string $categoryId the category id (as returned by getMobileLensCategories)
     * @param string $lang [optional] the language
     * @return Lmc_Ws_Response
     */
    public function getLensByCategory($token, $categoryId, $lang = null)
    {
        $response = new Lmc_Ws_Response(__METHOD__);
        $catalog = new Lmc_Ws_Catalog();

        try {
            $this->_session->load($token);
            $lang = $this->getLangIfInvalid($lang);
            $response->status = true;
            $response->data->categories = $catalog->getLensByCategory($categoryId, $lang);
            self::addOffersMobile($response->data->categories, $lang);
        } catch (Exception $e) {
            $response->error = true;
            $response->status = false;
            $response->errorMessage = $e->getMessage();
            $response->errorCode = $e->getCode();
        }

        return $this->addDebugAndReturnResponse($response);
    }