report/analytics/api

Revision as of 03:03, 13 August 2012 by Adam Olley (talk | contribs) (indicator_random)

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Moodle 2.2 This page describes the API used by the Engagement Analytics indicators and reporting mechanisms.

Main info

IMPORTANT This page is a WIP and does not reflect the final state of the engagement analytics API!

Indicator

File Layout

Indicators live in a folder in mod/analytics/indicator. The layout inside this folder follows the typical layout for a Moodle plugin. For example, inside the mod/analytics/indicator/myind folder we would have:

indicator.class.php 
Defines the indicator_myind class, which should extend the indicator base class.
renderer.php 
This contains the definition of the analyticsindicator_myind_renderer class, which should extend the analyticsindicator_renderer base class.
thresholds_form.php 
Defines the analyticsindicator_myind_thresholds_form which contains a function definition_inner for including on the report settings page.
lang/en/analyticsindicator_myind.php 
English language strings for this indicator. You can, of course, include other languages too. The language file must define at least the string giving the indicator a name, for example $string['pluginname'] = 'My Indicator';
db/install.xml, db/upgrade.php 
For creating any database tables required, as normal. See #Database_tables below.
db/access.php 
Defines any capabilities required by this question type. This is very rarely needed.

Functions

The indicator base class defines the following functions:

public function get_risk($userid, $courseid, $startdate = null, $enddate = null);
public function get_course_risks($startdate = null, $enddate = null);
private function get_risk_for_users($userids, $startdate, $enddate);
final private function get_cache();
final private function set_cache();
abstract protected function get_rawdata($startdate, $enddate);
abstract protected function calculate_risks(array $userids);
public function get_name();
protected function load_config();
public function save_config();

For the development of any new indicator, the functions you must implement are the abstracted ones:

abstract protected function get_rawdata($startdate, $enddate);
abstract protected function calculate_risks(array $userids);

If you have any settings (and most indicators probably will), you'll probably need:

protected function load_config();

Which can be used to setup any default values you need for when a user hasn't input any on their own.

Examples

indicator_random

Return a random risk score for each user.

defined('MOODLE_INTERNAL') || die();
require_once(dirname(__FILE__).'/../indicator.class.php');
 
class indicator_random extends indicator {
    protected function get_rawdata($startdate, $enddate) {
        global $DB;
        $rawdata = array();
        $someusers = get_enrolled_users($this->context);
        foreach ($someusers as $user) {
            $rawdata[$user->id] = mt_rand(0,100);
        }
        return $rawdata;
    }
 
    protected function calculate_risks(array $userids) {
        $risks = array();
        foreach ($userids as $userid) {
            if (!isset($this->rawdata[$userid])) {
                $risk = new stdClass();
                $risk->risk = 0;
                $risk->info = 'No risk, user had no data collected.';
                $risks[$userid] = $risk;
            }
 
            $risk = new stdClass();
            $value = $this->rawdata[$userid];
            if ($value > $this->config['max']) {
                $value = $this->config['max'];
            } else if ($value < $this->config['min']) {
                $value = $this->config['min'];
            }
            $risk->risk = $value;
            $risk->info = 'Random risk calcualted.';
            $risks[$userid] = $risk;
        }
        return $risks;
    }
 
    protected function load_config() {
        parent::load_config();
        $defaults = $this->get_defaults();
        foreach ($defaults as $setting => $value) {
            if (!isset($this->config[$setting])) {
                $this->config[$setting] = $value;
            }
        }
    }
 
    public function get_defaults() {
        $defaults = array();
        $defaults['min'] = 5;
        $defaults['max'] = 20;
        return $defaults;
    }
}

Helper Functions

See also