How can PHP be used to determine the domain or IP from which an image is being embedded?

When an image is embedded on a webpage, you can use PHP to determine the domain or IP address from which the image is being loaded by parsing the HTTP referer header. This can be useful for tracking where your images are being used or for implementing security measures to restrict image embedding from certain domains. 

$referer = $_SERVER['HTTP_REFERER'];
$url_parts = parse_url($referer);
$domain = $url_parts['host'];

echo "Image embedded from: " . $domain;

Keywords

PHP image embedding domain IP address gethostbyaddr

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