Returning multidimensional arrays in web services

by Mike Wilson.  

I'm putting together a web service to pass student information and assignment feedback comments to another system. It works quite nicely when I just return general student information in my personal_tutor_portal_returns() function, but I want to output a multidimensional array with the feedback data one level down.

I can't seem to get this to work.

Am I right in thinking I need an external_multiple_structure with two external_single_structures within it one for student data and another for feedback data?

Has anyone got a good example of something similar to what I'm trying to do?

Thanks for any help, the finish line is in sight on this one

Moodle 3.3.1

public static function personal_tutor_portal_parameters() {
    return new external_function_parameters(
            array(
            'email' => new external_value(PARAM_TEXT, 'Student email (lowercase)', VALUE_DEFAULT, 'something@blackhole.port.ac.uk'),
            'hash' => new external_value(PARAM_TEXT, 'Salted hash of username', VALUE_DEFAULT, '')
                 )
    );
}

public static function personal_tutor_portal($email = 'something@blackhole.port.ac.uk',$hash = '') {
    global $USER, $DB;
    $salt = 'YC*1!gduQ$jn^4';

    //Parameter validation
    $params = self::validate_parameters(self::personal_tutor_portal_parameters(),
            array('email'=>$email,
                  'hash'=>$hash));

    //do a hash check to ensure no messing with username
    if(md5($email.$salt)!=$hash){
        return "Sorry, the hash does not match.";
    }

    $user = $DB->get_record('user',array('email'=>$email));

    $sql = "SELECT
    greatest(ag.id) AS id,ag.assignment,ag.userid,ag.timecreated,ag.grader,u.firstname,u.lastname,ag.grade,greatest(afc.commenttext) AS commenttext,ag.timemodified,ass.name,ass.duedate,ass.markingworkflow,
    c.id AS courseid,c.fullname,c.shortname,ass.teamsubmission,cm.id AS cmid,
    auf.workflowstate,auf.id AS workflowstateid,m.name as modulename
    FROM
    {assign_grades} AS ag
    LEFT OUTER JOIN {assignfeedback_comments} AS afc ON afc.assignment = ag.assignment AND afc.grade = ag.id
    INNER JOIN {assign} AS ass ON ass.id = ag.assignment
    INNER JOIN {user} AS u ON u.id = ag.grader
    INNER JOIN {course} AS c ON ass.course = c.id
    INNER JOIN {course_modules} AS cm ON cm.instance = ag.assignment AND cm.course = c.id
    INNER JOIN {assign_user_flags} AS auf ON auf.assignment = ag.assignment
    INNER JOIN {modules} as m ON cm.module = m.id
    WHERE
    ag.userid = $user->id AND
    m.name = 'assign' AND
    auf.id = 1
    OR auf.id = 6
    GROUP BY greatest(ag.id),ag.assignment,ag.userid,ag.grade,ag.grader,ag.timecreated,u.firstname,u.lastname,u.email,ag.grade,afc.commenttext,ag.timemodified,ass.name,ass.duedate,ass.markingworkflow,c.id,
    c.fullname,c.shortname,ass.teamsubmission,cm.id,auf.workflowstate,auf.id,m.name
    ORDER BY
    c.fullname ASC,ag.timemodified DESC";

    $feedbacks = $DB->get_records_sql($sql,array());

    function academicyear($timestamp){
    /* Return academic year from a unix timestamp */

    $year = date('Y',$timestamp);
    $month = date('m',$timestamp);

        if ($month < 9){

            $aca = strtotime('-1 year',$timestamp);
            $aca = date('Y',$aca);

        }
        else $aca = $year;
        $text = $aca;

        return $text;
    }

      $portal = array(
                'source' => 'Moodle',
                'username' => $user->username,
                'firstname' => $user->firstname,
                'lastname' => $user->lastname,
                'email' => $user->email
            );

    foreach($feedbacks as $feedback){

        $academicyear = academicyear($feedback->timecreated);
        $rawcomment = strip_tags($feedback->commenttext);
        $marker = $feedback->firstname.' '.$feedback->lastname;
        $feedbackdate = date('d.m.Y',$feedback->timemodified);
    }

    return $portal;

}

public static function personal_tutor_portal_returns() {
    return new external_single_structure(
            array(
                'source' => new external_value(PARAM_TEXT, 'where data came from - moodle'),
                'username' => new external_value(PARAM_TEXT, 'username of student'),
                'firstname' => new external_value(PARAM_TEXT, 'first name of student'),
                'lastname' => new external_value(PARAM_TEXT, 'last name of student'),
                'email' => new external_value(PARAM_TEXT, 'email of student')
                )
        );

}