単純なプロキシ実装例

この例は、簡単な実装例です。よりセキュリティに配慮した実装が必要なケースがありますので、クロスオリジンアクセスの他の実装を参照の上利用を検討してください。

<?php
function file_get_contents_curl($url) {
	$headers = array(
	    "HTTP/1.0",
	    "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
//	    "Accept-Encoding:gzip ,deflate",
	    "Accept-Language:ja,en-us;q=0.7,en;q=0.3",
	    "Connection:keep-alive",
	    "User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:26.0) Gecko/20100101 Firefox/26.0"
	    );
    // **/
    $ch = curl_init();

    curl_setopt($ch, CURLOPT_AUTOREFERER, TRUE);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE);       
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);       

    $data = curl_exec($ch);
    curl_close($ch);

    return $data;
}

if($_GET["file"]){
	
	$referer = isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : null;
	// accept only referrer within this site
	header("Access-Control-Allow-Origin: " . "*"); // MUST SET for CORS
	if (preg_match("|^https?://svgmap\.org|", $referer) || preg_match("|^https?://www\.svgmap\.org|", $referer)) {
		if ( $_GET["type"]){
			header("Content-type: " . $_GET["type"]);
		} else {
			if(strpos($_GET["file"],'png')){
				header("Content-type: image/png");
			} else {
				header("Content-Type:image/jpeg;");
			}
		}
		echo file_get_contents_curl( urldecode($_GET["file"]), true);
	} else {
		echo "ERR : referer : " .  $referer;
	}
} else {
	foreach (getallheaders() as $name => $value) {
		echo "$name: $value<br>";
	}
	foreach ($_GET as $key => $value) {
	echo "GET Key:".$key.",  Value:".$value."<br>";
	}
	echo "referrer: ".$_SERVER['HTTP_REFERER'];
}
?>