plugins/ExampleTracker/Columns/ExampleActionDimension.php

<?php

/**
 * Matomo - free/libre analytics platform
 *
 * @link    https://matomo.org
 * @license https://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
 */

namespace Piwik\Plugins\ExampleTracker\Columns;

use Piwik\Common;
use Piwik\Plugin\Dimension\ActionDimension;
use Piwik\Tracker\ActionPageview;
use Piwik\Tracker\Request;
use Piwik\Tracker\Visitor;
use Piwik\Tracker\Action;

/**
 * This example dimension recognizes a new tracking url parameter that is supposed to save the keywords that were used
 * on a certain page. Please note that dimension instances are usually cached during one tracking request so they
 * should be stateless (meaning an instance of this dimension will be reused if requested multiple times).
 *
 * See {@link https://developer.matomo.org/api-reference/Piwik/Plugin\Dimension\ActionDimension} for more information.
 */
class ExampleActionDimension extends ActionDimension
{
    /**
     * The name of the dimension which will be visible for instance in the UI of a related report and in the mobile app.
     * @return string
     */
    protected $nameSingular = 'ExampleTracker_DimensionName';

    /**
     * This will be the name of the column in the log_link_visit_action table if a $columnType is specified.
     * @var string
     */
    protected $columnName = 'example_action_dimension';

    /**
     * If a columnType is defined, we will create this a column in the MySQL table having this type. Please make sure
     * MySQL will understand this type. Once you change the column type the Piwik platform will notify the user to
     * perform an update which can sometimes take a long time so be careful when choosing the correct column type.
     * @var string
     */
    protected $columnType = 'VARCHAR(255) DEFAULT NULL';

    /**
     * The type of the dimension is automatically detected by the columnType. If the type of the dimension is not
     * detected correctly, you may want to adjust the type manually. The configured type will affect how the dimension
     * is formatted in the UI.
     * @var string
     */
    // protected $type = self::TYPE_TEXT;

    /**
     * By defining a segment a user will be able to filter their visitors by this column. For instance
     * show all actions only considering users having more than 10 achievement points. If you do not want to define a
     * segment for this dimension, simply leave the name empty.
     */
    protected $segmentName = 'keywords';

    protected $acceptValues = 'Here you should explain which values are accepted/useful for segments: Any word, for instance MyKeyword1, MyKeyword2';

    /**
     * This event is triggered before a new action is logged to the log_link_visit_action table. It overwrites any
     * looked up action so it makes usually no sense to implement both methods but it sometimes does. You can assign
     * any value to the column or return boolan false in case you do not want to save any value.
     *
     * @return mixed|false
     */
    public function onNewAction(Request $request, Visitor $visitor, Action $action)
    {
        if (!($action instanceof ActionPageview)) {
            // save value only in case it is a page view.
            return false;
        }

        $value = Common::getRequestVar('my_page_keywords', false, 'string', $request->getParams());

        if (false === $value) {
            return $value;
        }

        $value = trim($value);

        return substr($value, 0, 255);
    }

    /**
     * If the value you want to save for your dimension is something like a page title or page url, you usually do not
     * want to save the raw value over and over again to save bytes in the database. Instead you want to save each value
     * once in the log_action table and refer to this value by its ID in the log_link_visit_action table. You can do
     * this by returning an action id in "getActionId()" and by returning a value here. If a value should be ignored
     * or not persisted just return boolean false. Please note if you return a value here and you implement the event
     * "onNewAction" the value will be probably overwritten by the other event. So make sure to implement only one of
     * those.
     *
     * @param Request $request
     * @param Action $action
     *
     * @return false|mixed
    public function onLookupAction(Request $request, Action $action)
    {
        if (!($action instanceof ActionPageview)) {
            // save value only in case it is a page view.
            return false;
        }

        $value = Common::getRequestVar('my_page_keywords', false, 'string', $request->getParams());

        if (false === $value) {
            return $value;
        }

        $value = trim($value);

        return substr($value, 0, 255);
    }
     */

    /**
     * An action id. The value returned by the lookup action will be associated with this id in the log_action table.
     * @return int
    public function getActionId()
    {
        return Action::TYPE_PAGE_URL;
    }
     */
}