#!/usr/local/bin/php
<?
function get_tag_data_r($tags,$string,$tag_data) {
//homebrew XML parser-like thingy
//recursively get data between an XML tags
//we use this to parse the output from the USPS

$num_tags=count($tags);
if ($num_tags!=1) {
 $num_tags_i=count($tags[0]);
 for ($i=0;$i<$num_tags_i;$i++) {
  $tag_i=preg_replace("/<|>/","",$tags[0][$i]);
  $string_i=preg_replace("/(.*?)(<$tag_i>)(.*?)(<\/$tag_i>)(.*)/is","\${3}",$string);
  $tag_data=get_tag_data_r(array_slice($tags,1),$string_i,$tag_data);
 }
} else {
 $num_tags_j=count($tags[0]);
 for ($j=0;$j<$num_tags_j;$j++) {
  $tag=preg_replace("/<|>/","",$tags[0][$j]);
  $tag_data_j[]=preg_replace("/(.*?)(<$tag>)(.*?)(<\/$tag>)(.*)/is","\${3}",$string);
 }
 $tag_data[]=$tag_data_j;
}

return $tag_data;

}

//*****The meat/tofu of the program is below*****

//form the Request to ZipCodeLookup w/an address
//**You have to use your own username and password**
$url='http://testing.shippingapis.com/ShippingAPITest.dll?API=ZipCodeLookup&XML=';
$msg='<ZipCodeLookupRequest%20USERID="XXXXXXXXX"%20PASSWORD="XXXXXXXXX"><Address ID="0"><Address1></Address1><Address2>6406 Ivy Lane</Address2><City>Greenbelt</City><State>MD</State></Address></ZipCodeLookupRequest>';

//get the response from the USPS
$newurl = $url . urlencode($msg);
echo "-We say to the USPS-\n";
echo "$newurl\n\n";
$contents=file_get_contents($newurl);
echo "-The USPS says-\n";
echo "$contents\n\n";

//handle the expected XML output containted in $contents with the function defined above:
//
//**The test server only returns Errors, so we're going to strip stuff out of the XML Error**
//
//This function was built really fast and does not handle a lot of stuff (like attributes)
//but it is more than what I found when I started so I'm passing it along.  It basically
//just lets you grab stuff in an XML document that you can easily navigate to <Error> -> <Number>,
//<Error> -> <Description>, and <Error> -> <Source> in this example.  Specifying <Error> at 
//the higher level is actually optional here since <Number>,<Description>, and <Source> are unique. 
//

$tag_data=get_tag_data_r(array(array("<Error>"),array("<Number>","<Description>","<Source>")),$contents,array());

echo "-We parse the XML Error-\n";
echo "<Number>:\t{$tag_data[0][0]}\n";
echo "<Description>:\t{$tag_data[0][1]}\n";
echo "<Source>:\t{$tag_data[0][2]}\n";

?>