aMember (site.php): add Open Graph Meta to Product Page

site.php

<?php

Am_Di::getInstance()->blocks->add('cart/product/title', new Am_Block_Base(null, 'ogp-me', null, function(Am_View $v) {

    if ($v->displayProductDetails) {
        /** @var Product $product */
        $product = $v->product;

        $product_url = $product->path ?
            $v->surl('product/' . urlencode($product->path), false) :
            $v->surl("cart/index/product/id/{$product->pk()}", false);

        $meta = [
            'og:type' => 'og:product',
            'og:title' => $product->title,
            'og:image' => $v->surl("data/public/{$product->img_path}", false),
            'og:description' => $product->getDescription(false),
            'og:url' => $product_url,
            'product:price:amount' => $product->getBillingPlan()->first_price,
            'product:price:currency' => $product->getBillingPlan()->currency,
        ];

        $out = '';
        foreach ($meta as $property => $content) {
            $out .= sprintf(
                '<meta property="%s" content="%s" />%s',
                Am_Html::escape($property),
                Am_Html::escape($content),
                "\n"
            );
        }

        $v->placeholder("head-start")->append($out);
    }

}));