Flash などから Youtube の動画を読み込む為のプロキシ。後は crossdomain.xml を設置

youtube_proxy.php

<?php
// usage:
// youtube_proxy.php?url=http%3a%2f%2fwww%2eyoutube%2ecom%2fwatch%3fv%3dmxPXPv3oNY4%26feature%3dfvsr

define('YOUTUBE_DOMAIN', 'www.youtube.com');

// fmt(優先度：左->右)
$fmtTbl = array(5, 18, 34, 22, 37);

$url = isset($_GET['url']) ? rawurldecode($_GET['url']) : '';
$pattern = '/^http:\/\/' . preg_quote(YOUTUBE_DOMAIN) . '\//';

if (preg_match($pattern, $url)) {
    $html = @file_get_contents($url);

    if (preg_match('/"fmt_url_map": "([^"]*)",/i', $html, $matches)) {
        $urls = explode(',', $matches[1]);
        $flv  = array();
        foreach ($urls as $url) {
            if (preg_match('/^(\d+)\|(.*?)$/', $url, $matches)) {
                $flvUrl = urldecode($matches[2]);
                $flvUrl = str_replace('\u0026', '&', $flvUrl);
                $flvUrl = str_replace('\\', '', $flvUrl);
                $flv[(int)$matches[1]] = $flvUrl;
            }
    	}
        
        if ($flv) {
            foreach ($fmtTbl as $fmt) {
                if (isset($flv[$fmt])) {
                    header('Content-type: video/x-flv');
                    readfile($flv[$fmt]);
                    exit;
                }
            }
        }
    }
}

header('HTTP/1.0 404 Not Found');