<?php
 
function extrairHostPorReferencia($url){
	// Extraí tudo que estiver depois das duas primeiras barras "//
	$depois = strstr($url, "//");
 
	// Elimina os dois primeiros caracteres, que são "//"
	$depois = substr($depois, 2) . "\n";
 
	// Extraí tudo que estiver antes da primeira barra "/"
	$antes  = strstr($depois, '/', true);
	return $antes;
}
 
$url  = "https://docs.google.com/uc?id=0B7zY19LCJa8XeXZtWklZbFBEVG8&export=download";
$site = extrairHostPorReferencia($url);
echo $site. "\n";

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