/home/arranoyd/magicraft/wp-content/plugins/cloudflare/src/WordPress/HTTP2ServerPush.php
<?php
// TODO:
// Get rid of $GLOBALS and use static variables
// Make class functions non-static
// Add debug logs. Need dependency injection of logger to this class
namespace CF\WordPress;
class HTTP2ServerPush
{
private static $initiated = false;
public static function init()
{
if (!self::$initiated) {
self::initHooks();
}
ob_start();
}
public static function initHooks()
{
self::$initiated = true;
add_action('wp_head', array('\CF\WordPress\HTTP2ServerPush', 'http2ResourceHints'), 99, 1);
add_filter('script_loader_src', array('\CF\WordPress\HTTP2ServerPush', 'http2LinkPreloadHeader'), 99, 1);
add_filter('style_loader_src', array('\CF\WordPress\HTTP2ServerPush', 'http2LinkPreloadHeader'), 99, 1);
}
public static function http2LinkPreloadHeader($src)
{
if (strpos($src, home_url()) !== false) {
$preload_src = apply_filters('http2_link_preload_src', $src);
if (!empty($preload_src)) {
$newHeader = sprintf(
'Link: <%s>; rel=preload; as=%s',
esc_url(self::http2LinkUrlToRelativePath($preload_src)),
sanitize_html_class(self::http2LinkResourceHintAs(current_filter()))
);
// If the current header size is larger than 3KB (3072 bytes)
// ignore following resources which can be pushed
// This is a workaround for Cloudflare's 8KB header limit
// and fastcgi default 4KB header limit
$headerAsString = implode(' ', headers_list());
// +2 comes from the last CRLF since it's two bytes
$headerSize = strlen($headerAsString) + strlen($newHeader) + 2;
if ($headerSize > 3072) {
error_log('Cannot Server Push (header size over 3072 Bytes).');
return $src;
}
header($newHeader, false);
$GLOBALS['http2_'.self::http2LinkResourceHintAs(current_filter()).'_srcs'][] = self::http2LinkUrlToRelativePath($preload_src);
}
}
return $src;
}
/**
* Render "resource hints" in the <head> section of the page. These encourage preload/prefetch behavior
* when HTTP/2 support is lacking.
*/
public static function http2ResourceHints()
{
$resource_types = array('script', 'style');
array_walk($resource_types, function ($resource_type) {
if (is_array($GLOBALS["http2_{$resource_type}_srcs"])) {
array_walk($GLOBALS["http2_{$resource_type}_srcs"], function ($src) use ($resource_type) {
printf('<link rel="preload" href="%s" as="%s">', esc_url($src), esc_html($resource_type));
});
}
});
}
/**
* Convert an URL with authority to a relative path.
*
* @param string $src URL
*
* @return string mixed relative path
*/
public static function http2LinkUrlToRelativePath($src)
{
return '//' === substr($src, 0, 2) ? preg_replace('/^\/\/([^\/]*)\//', '/', $src) : preg_replace('/^http(s)?:\/\/[^\/]*/', '', $src);
}
/**
* Maps a WordPress hook to an "as" parameter in a resource hint.
*
* @param string $current_hook pass current_filter()
*
* @return string 'style' or 'script'
*/
public static function http2LinkResourceHintAs($current_hook)
{
return 'style_loader_src' === $current_hook ? 'style' : 'script';
}
}