PHP plugin that controls your too many database connections

Code:
<?php
//** CHECK DB LIMITS

	//--> Make a database-connection
			[Make a connectiont with your DB here]
			
			$test = explode('  ', mysql_stat());
			mysql_close();
			
			$threads = preg_replace("Threads: ", "", $test[1]);
								
	//--> If to many DB threads, disable pages for visitors accept user coming from some sites (eg. your own, google, monitoring sites)
						
			// +90 threads : Block all traffic untill the DB calmes down again (probably in a few seconds)
			if($threads > 90) :			
				$block = true;
				if($block == true) : 
						echo "We're receiving to much traffic at the moment, please <a href=\"" . $_SERVER["REQUEST_URI"] . "\">RETRY</a> (Code T_$threads)"; die; 
				endif;

			// +70 threads : block traffic but allow traffic coming from your own site, google and monitoring websites
			elseif($threads > 70) :			
				$block = true;
				$allowed = array("[yoursitename]", "amazon", "google", "pingdom");
												
				foreach ($allowed as $k => $v) :
					// allow google and pingdom crawler
					if(strpos(gethostbyaddr($_SERVER['REMOTE_ADDR']), $v)) : $block = false; break;
					// allow traffic coming from your own site
					elseif(strpos(getenv("HTTP_REFERER"), $v)) : $block = false; break; endif;
				endforeach;
				
				// block all other traffic untill the DB calmes down again
				if($block == true) : 
						echo "We're receiving to much traffic at the moment, please <a href=\"" . $_SERVER["REQUEST_URI"] . "\">RETRY</a> (Code T_$threads)"; die; 
				endif;

			// +50 threads : block some traffic but be sure search engine spiders don't crawl your blocked page
			elseif($threads > 50) :				
				if(strpos($_SERVER["REQUEST_URI"], "news")) :
						$block = true;
						$allowed = array("[yoursitename]", "amazon", "baidu", "bit", "crawl", "google", "msn", "pingdom", "tinyurl", "twitter", "yahoo", "yandex");
						
						foreach ($allowed as $k => $v) :
								if(strpos(gethostbyaddr($_SERVER['REMOTE_ADDR']), $v)) : $block = false; break;
								elseif(strpos(getenv("HTTP_REFERER"), $v)) : $block = false; break; endif;
						endforeach;
						
						if(getenv("HTTP_REFERER") != "") : $block = false; endif;
						
						if($block == true) : 
								echo "We're receiving to much traffic at the moment, please <a href=\"" . $_SERVER["REQUEST_URI"] . "\">RETRY</a> (Code T_$threads)"; die; 
						endif;
				endif;
			endif;
?>