This PHP class allows you to connect to Sierra's API and make queries.
The example gets information on bib ID 3996024 and limits the results to 20 records only including the fields id, location, and status.
include('Sierra.php');
$s = new Sierra(array(
'endpoint' => 'Sierra REST API Endpoint (ie https://lib.example.edu/iii/sierra-api/v1/)',
'key' => 'Sierra Client Key',
'secret' => 'Sierra Client Secret'
'tokenFile' => 'Location to the temp file to keep token infomation, default: /tmp/SierraToken'
));
$bibInformation = $s->query('items', array(
'bibIds' => '3996024',
'limit' => '20',
'fields' => 'id,location,status'
));