API.php

<?php
/**
 * Piwik - Open source web analytics
 *
 * @link http://piwik.org
 * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
 *
 * @category Piwik_Plugins
 * @package Piwik_ExampleUI
 */
use Piwik\Period_Range;

/**
 * ExampleUI API is also an example API useful if you are developing a Piwik plugin.
 *
 * The functions listed in this API are returning the data used in the Controller to draw graphs and
 * display tables. See also the ExampleAPI plugin for an introduction to Piwik APIs.
 *
 * @package Piwik_ExampleUI
 */
class Piwik_ExampleUI_API
{
    static private $instance = null;

    static public function getInstance()
    {
        if (self::$instance == null) {
            self::$instance = new self;
        }
        return self::$instance;
    }

    public function getTemperaturesEvolution($date, $period)
    {
        $period = new Period_Range($period, 'last30');
        $dateStart = $period->getDateStart()->toString('Y-m-d'); // eg. "2009-04-01"
        $dateEnd = $period->getDateEnd()->toString('Y-m-d'); // eg. "2009-04-30"

        // here you could select from your custom table in the database, eg.
        $query = "SELECT AVG(temperature)
					FROM server_temperatures
					WHERE date > ?
						AND date < ?
					GROUP BY date
					ORDER BY date ASC";
        //$result = Piwik_FetchAll($query, array($dateStart, $dateEnd));
        // to keep things simple, we generate the data
        foreach ($period->getSubperiods() as $subPeriod) {
            $server1 = mt_rand(50, 90);
            $server2 = mt_rand(40, 110);
            $value = array('server1' => $server1, 'server2' => $server2);
            $temperatures[$subPeriod->getLocalizedShortString()] = $value;
        }
        return Piwik_DataTable::makeFromIndexedArray($temperatures);
    }

    // we generate an array of random server temperatures
    public function getTemperatures()
    {
        $xAxis = array(
            '0h', '1h', '2h', '3h', '4h', '5h', '6h', '7h', '8h', '9h', '10h', '11h',
            '12h', '13h', '14h', '15h', '16h', '17h', '18h', '19h', '20h', '21h', '22h', '23h',
        );
        $temperatureValues = array_slice(range(50, 90), 0, count($xAxis));
        shuffle($temperatureValues);
        $temperatures = array();
        foreach ($xAxis as $i => $xAxisLabel) {
            $temperatures[$xAxisLabel] = $temperatureValues[$i];
        }

        return Piwik_DataTable::makeFromIndexedArray($temperatures);
    }

    public function getPlanetRatios()
    {
        $planetRatios = array(
            'Mercury' => 0.382,
            'Venus'   => 0.949,
            'Earth'   => 1.00,
            'Mars'    => 0.532,
            'Jupiter' => 11.209,
            'Saturn'  => 9.449,
            'Uranus'  => 4.007,
            'Neptune' => 3.883,
        );
        // convert this array to a DataTable object
        return Piwik_DataTable::makeFromIndexedArray($planetRatios);
    }

    public function getPlanetRatiosWithLogos()
    {
        $planetsDataTable = $this->getPlanetRatios();
        foreach ($planetsDataTable->getRows() as $row) {
            $row->addMetadata('logo', "plugins/ExampleUI/images/icons-planet/" . strtolower($row->getColumn('label') . ".png"));
            $row->addMetadata('url', "http://en.wikipedia.org/wiki/" . $row->getColumn('label'));
        }
        return $planetsDataTable;
    }
}