Callbacks

When do I need a callback?

Callbacks get used to converting found values of a CSV file into the required types, which must then get stored in the database.

The default CSV format of Magento 2 allows, e.g., the following values:

Catalog
Search
Catalog, Search
Not Visible Individually

Visibility column:

The Visibility column expects integer values, those values cannot get stored in the corresponding database column.

A callback converts the string to the correct value type; for the Visibility column, the class TechDivision\\Import\\Product\\Callbacks\\VisibilityCallback already exists.

Default callbacks to convert the standard Magento 2 attributes found in a CSV file get provided by default.

When a new custom attribute gets added, e.g., a setup script, Pacemaker Import Community tries to find the best matching callback depends on the attributes frontend_input value.

Pacemaker Import Community provides the following frontend_input type callbacks by default:

select
multiselect
boolean

Callbacks for additional input types will be part of upcoming releases and can be used or implemented by developers using Pacemaker Import Community in their project at any time.

A callback is necessary to manipulate a VALUE of a specific column per row of a CSV file.

Please note that a custom callback replaces the default callback and is not appended.

How to implement a callback?

To implement a callback, extend the abstract class TechDivision\Import\Callbacks\AbstractCallback.

The callback handle() method expects the calling observer as a parameter; in return providing the getAttributeValue() method allows you to access the value to be processed.

Example

The callback must return the processed value so that the following callbacks can also process it:

VisibilityCallback.php

<?php

namespace TechDivision\Import\Product\Callbacks;

use TechDivision\Import\Observers\AttributeCodeAndValueAwareObserverInterface;

/**
 * A callback implementation that converts the passed visibility.
 *
 * @author    Tim Wagner <t.wagner@techdivision.com>
 * @copyright 2016 TechDivision GmbH <info@techdivision.com>
 * @license   http://opensource.org/licenses/osl-3.0.php Open Software License (OSL 3.0)
 * @link      https://github.com/techdivision/import-product
 * @link      http://www.techdivision.com
 */
class VisibilityCallback extends AbstractCallback
{

    /**
     * Will be invoked by a observer it has been registered for.
     *
     * @param \TechDivision\Import\Observers\AttributeCodeAndValueAwareObserverInterface|null $observer The observer
     *
     * @return mixed The modified value
     */
    public function handle(AttributeCodeAndValueAwareObserverInterface $observer = null)
    {

        // set the observer
        $this->setObserver($observer);

        // replace the passed attribute value into the visibility ID
        return $this->getSubject()->getVisibilityIdByValue($observer->getAttributeValue());
    }
}

The callback key is the column name; this callback must get called.
The callback gets called for each column visibility for each row of the processed CSV file.

Callbacks

When do I need a callback?

How to implement a callback?

Example

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