Sample customised filter api to help find Notes that are related to multiple Contacts at the same time, with a custom many to many relationship

CustomNotesFilterApi.php

<?php

// Enrico Simonetti
// enricosimonetti.com
//
// 2017-12-08 tested on Sugar 7.9.2.0
// Sample customised filter api to help find Notes that are related to multiple Contacts at the same time, with a custom many to many relationship 
// eg: {{url}}/rest/v10/Notes?contact_id[]=<first id>&contact_id[]=<second id> will only return Notes that are related to both contacts at the same time
//
// file: custom/modules/Notes/clients/base/api/CustomNotesFilterApi.php

class CustomNotesFilterApi extends FilterApi
{
    public function registerApiRest()
    {
        return parent::registerApiRest();
    }

    public function filterListSetup(ServiceBase $api, array $args, $acl = 'list')
    {
        $original_output = parent::filterListSetup($api, $args, $acl);
  
        if(!empty($args['contact_id'])) {

            $contact_ids = array_unique($args['contact_id']);

            $table_name = 'notes_contacts_1_c';
            $contacts_id_field_name = 'notes_contacts_1contacts_idb';
            $notes_id_field_name = 'notes_contacts_1notes_ida';

            $q = new SugarQuery();
            $q->from(BeanFactory::getBean('Notes'));
            $q->select->field(array(array('notes.id', 'note_id')));
            $q->select->fieldRaw('cntct.'.$contacts_id_field_name, 'contact_id');
            $q->joinTable($table_name,
                array(
                    'alias' => 'cntct',
                    'joinType' => 'inner',
                )
            )->on()->equalsField('cntct.'.$notes_id_field_name, 'notes.id')->equals('cntct.deleted', 0)
            ->in('cntct.'.$contacts_id_field_name, $contact_ids);

            //$compiled = $q->compile();
            //$GLOBALS['log']->fatal($compiled->getSQL().' '.print_r($compiled->getParameters(), true));

            $records = $q->execute();

            $to_query = array();
            $grouped_records = array();
            if(!empty($records)) {
                foreach($records as $record) {
                    $grouped_records[$record['note_id']][] = array($record['contact_id'] => $record['contact_id']);
                }
                if(!empty($grouped_records)) {
                    foreach($grouped_records as $key => $grouped_record) {
                        if(count($grouped_record) == count($contact_ids)) {
                            $to_query[$key] = $key;
                        }
                    }
                }
            }

            // add my condition, even if empty (means no matches, and should show no records)
            $original_output['1']->where->in('id', $to_query);
        }

        return $original_output;
    }
}