Konstantin G.
Varnish ESI block
Edge Side Includes (ESI) are special directives that you can use to include web pages in other web pages.
An example:
<div>
<esi:include src="http://domain.com/index.php/page_cache/block/esi/blocks"/>
</div>
Varnish fetches content from http://domain.com/index.php/page_cache/block/esi/blocks
and replace the <esi>
tag with it.
Commerce and Varnish ESI
The Commerce framework creates an ESI tag when the following conditions are met:
- The caching application is set to
Varnish Cache
- A XML layout
block
element is added with attl
attribute
Example
cms_index_index.xml
:
<referenceContainer name="content">
<block class="Magento\Framework\View\Element\Template" template="Magento_Paypal::esi.phtml" ttl="30"/>
</referenceContainer>
In the example above, the block
element adds content from the esi.phtml
template to a homepage and Varnish automatically updates it every 30 seconds.
Limitations
Currently, Varnish does not support ESI over HTTPS so it automatically switches to HTTP.
Magento\PageCache\Observer\ProcessLayoutRenderElement
:
private function _wrapEsi(
\Magento\Framework\View\Element\AbstractBlock $block,
\Magento\Framework\View\Layout $layout
) {
....
// Varnish does not support ESI over HTTPS must change to HTTP
$url = substr($url, 0, 5) === 'https' ? 'http' . substr($url, 5) : $url;
return sprintf('<esi:include src="%s" />', $url);
}
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