Retrieve a query ID set from an ArcGIS Server request.

example.php

<?php

// create the query
$query = array(
	'f' => 'json', // return json
	'returnIdsOnly' => 'true', // return id set only
	'where' => "OWNERNME1 LIKE '%sm%' OR OWNERNME2 LIKE '%sm%'", // the where clause
);

// query url - TaxParcel/TaxParcelQuery service - TaxParcelPublishing layer
$url = 'http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/TaxParcel/TaxParcelQuery/MapServer/0/query';

// execute the remote call
$remote_response = wp_remote_post( $url, array(
	'body' => $query
));

// check for a WP_Error object, if so, return it
if( is_wp_error( $remote_response ) )
	return $remote_response;

// grab the reponse body as a JSON string
$response_body = wp_remote_retrieve_body($remote_response);