This article is written for an old version of the Virtual Earth platform. While still available for reference purposes, it is unlikely to work if implemented.

When developing Virtual Earth applications it is annoying to have to reload the map tiles every time. Why not not write a simple proxy page in PHP to cache the tiles on your local network?

Change in MapControl.js

VE_MapControl.tileUrlPrefixes=["http://h/maps/cache.php?c=0&p=",
"http://h/maps/cache.php?c=1&p=","http://h/maps/cache.php?c=2&p=",
"http://h/maps/cache.php?c=3&p="];

(h is only an alias for our development machine)

Create directories 0-3 in the "maps/" directory given above

Install HTTP_Request from the php pear repository

Place cache.php into "maps/"

<?php
$f=$_GET['c'].'/'.str_replace('?g=1','',$_GET['p']);

function pumpout($f)
{
   $expire = 10080;  // Minutes
   $exp_gmt = gmdate("D, d M Y H:i:s", time() + $expire * 60) ." GMT";
   $mod_gmt = gmdate("D, d M Y H:i:s", getlastmod()) ." GMT";
   header("Expires: " . $exp_gmt);
   header("Last-Modified: " . $mod_gmt);
   header("Cache-Control: public, max-age=" . $expire * 60);
   header('Content-Type: image/png');
   readfile($f);
}

if (file_exists($f))
{
   pumpout($f);
   exit();
}
 
require_once("pear/Request.php");

function mntffile($s)
{
	PEAR::SetErrorHandling(PEAR_ERROR_RETURN);
	$obj = &new HTTP_Request($s);
	$obj -> _timeout=5;
	
	if (@PEAR::isError(@$obj -> sendRequest())) {
		return false;
	}
	
	if ($obj -> getResponseCode()==200)
	{
		return $obj -> getResponseBody();
	}
	else
	{
		return false;
	}
}

$url='http://tiles'.$_GET['c'].'.virtualearth.msn.com/tiles/'.$_GET['p'];

$l=fopen('log','a');
fwrite($l,$url."\n");
fclose($l);

$i=0;
while (true)
{
	$data=mntffile($url);
	if ($data!=false) { break; }
	$i++;
	if ($i>5) { break; }
}

if ($data!=false)
{
	$h=fopen($f,"w");
	fwrite($h,$data);
	fclose($h);
	pumpout($f);
}

?>

Article contributed by MNT. Have you got something to contribute?