Simple PHP function to check if USPS package has been accepted / picked up using official USPS API

usps_accepted_at.php

<?php

function usps_picked_up( $tracking_number ) {
	if( empty( $tracking_number ) || !ctype_alnum( $tracking_number ) ) {
		return false;
	}

  	$user_id = "YOUR_USER_ID";
	$usps_api_uri = "http://production.shippingapis.com/shippingAPI.dll";
	$xml = rawurlencode("<TrackRequest USERID=\"". $user_id ."\">
	<TrackID ID=\"". $tracking_number ."\" />
	</TrackRequest>");
	$request = $usps_api_uri ."?API=TrackV2&XML=". $xml;
	$ch = curl_init();
	curl_setopt($ch, CURLOPT_URL, $request);
	curl_setopt($ch, CURLOPT_HEADER, false);
	curl_setopt($ch, CURLOPT_HTTPGET, true);
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

	$result = curl_exec($ch);
	if ( curl_errno( $ch ) ) {
		return false;
	}
	curl_close($ch);

	$result_object = new SimpleXMLElement($result);

	$picked_up = false;
	if( !empty( $result_object->TrackInfo->TrackDetail ) ) {
		foreach( $result_object->TrackInfo->TrackDetail as $track_detail ) {
			if( strpos( $track_detail, 'USPS in possession' ) !== false ||
			    strpos( $track_detail, 'Accepted at') !== false ) {
				$picked_up = true;
			}
		}
	}

	return $picked_up;
}

?>