#12371 allows to add handlers via di

[thomas-kl1]

This PR allows to add handlers thanks to the di.xml configuration file.

Description (*)

Today we can't add easily handlers to manage the output of a product attribute by using the output helper.
The solution is add a plugin on getHandlers methods, but you have to check in your side that you didn't already added the handler.
An other solution is to add the handlers once on the instantiation of the helper.

Fixed Issues (if relevant)

1. Adding a handler to the Magento\Catalog\Helper\Output Class #12371: Adding a handler to the Magento\Catalog\Helper\Output Class

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds are green)

[m2-assistant]

Hi @thomas-kl1. Thank you for your contribution
Here is some useful tips how you can test your changes using Magento test environment.
Add the comment under your pull request to deploy test or vanilla Magento instance:

• @magento give me test instance - deploy test instance based on PR changes
• @magento give me 2.3-develop instance - deploy vanilla Magento instance

For more details, please, review the Magento Contributor Guide documentation.

[sky-hub]

This implementation has a design issue and will not work as intended.

1. Given the following di.xml configuration:

<type name="Magento\Catalog\Helper\Output">
        <arguments>
            <argument name="handlers" xsi:type="array">
                <item name="my-attribute-handler" xsi:type="string">MyProject\MyModule\Model\Product\Attribute\MyAttributeHandler</item>
            </argument>
        </arguments>
    </type>

the implementation will fail because method get handlers will return always empty because variable $method will always be equal to productAttribute @see \Magento\Catalog\Helper\Output::process() and method getHandler() returns return $this->_handlers[strtolower($method)] ?? [];

2. Given the following di.xml configuration:

<type name="Magento\Catalog\Helper\Output">
        <arguments>
            <argument name="handlers" xsi:type="array">
                <item name="productAttribute" xsi:type="string">MyProject\MyModule\Model\Product\Attribute\MyAttributeHandler</item>
            </argument>
        </arguments>
    </type>

the handler will return correct class but only one handler can be added, meaning you can not have different handlers for different attributes, or adding handlers from multiple modules without replacing the existing handlers.

Can you please provide your di.xml configuration?

Update:
A solution to make this implementation work will be to use $handler['productAttribute'] as composite class and add handlers for each attribute in the composite class.
Example:

<type name="Magento\Catalog\Helper\Output">
        <arguments>
            <argument name="handlers" xsi:type="array">
                <item name="productAttribute" xsi:type="object">MyProject\MyModule\Model\Product\Attribute\ProductAttributeHandlerComposite</item>
            </argument>
        </arguments>
    </type>

<type name="MyProject\MyModule\Model\Product\Attribute\ProductAttributeHandlerComposite">
        <arguments>
            <argument name="my-attribute-code" xsi:type="object">MyProject\MyModule\Model\Product\Attribute\MyAttributeHandler</argument>
            <argument name="my-second-attribute-code" xsi:type="object">MyProject\MyModule\Model\Product\Attribute\MyAttributeHandler</argument>
        </arguments>
    </type>

but is not very clear for end developers how the implementation works.

[thomas-kl1]

@sky-hub Actually it works as following, no need to make it more complex:

<type name="Magento\Catalog\Helper\Output">
    <arguments>
        <argument name="handlers" xsi:type="array">
            <item name="productattribute" xsi:type="array">
                <item name="handlerA" xsi:type="object">Vendor\Module\Handler\A</item>
                <item name="handlerB" xsi:type="object">Vendor\Module\Handler\B</item>
            </item>
        </argument>
    </arguments>
</type>

However a new handler interface should be introduced, method_exists is the worst.

[magento-engcom-team]

Hi @sidolov, thank you for the review.
ENGCOM-5757 has been created to process this Pull Request
✳️ @sidolov, could you please add one of the following labels to the Pull Request?

Label	Description
Auto-Tests: Covered	All changes in Pull Request is covered by auto-tests
Auto-Tests: Not Covered	Changes in Pull Request requires coverage by auto-tests
Auto-Tests: Not Required	Changes in Pull Request does not require coverage by auto-tests

[orlangur]

Please import it similar to strtolower.

After changes are applied and all builds are green, please squash them into a single commit so that we have perfectly clean history 😉

[magento-engcom-team]

Hi @orlangur, thank you for the review.
ENGCOM-5757 has been created to process this Pull Request
✳️ @orlangur, could you please add one of the following labels to the Pull Request?

Label	Description
Auto-Tests: Covered	All changes in Pull Request is covered by auto-tests
Auto-Tests: Not Covered	Changes in Pull Request requires coverage by auto-tests
Auto-Tests: Not Required	Changes in Pull Request does not require coverage by auto-tests

[engcom-Bravo]

✔️ QA Passed

[m2-assistant]

Hi @thomas-kl1, thank you for your contribution!
Please, complete Contribution Survey, it will take less than a minute.
Your feedback will help us to improve contribution process.

[nahall]

Is there documentation somewhere about how to now create a product attribute output helper since this code change was made? I see code samples from before the change that don't work but no code sample of how it is actually now designed to work. Thanks.

[thomas-kl1]

@nahall No there is no documentation as far as I know,

<type name="Magento\Catalog\Helper\Output">
    <arguments>
        <argument name="handlers" xsi:type="array">
            <item name="productattribute" xsi:type="array">
                <item name="myHandler" xsi:type="object">Vendor\Module\Model\Handler\Output</item>
            </item>
            <item name="categoryattribute" xsi:type="array">
                <item name="myHandler" xsi:type="object">Vendor\Module\Model\Handler\Output</item>
            </item>
        </argument>
    </arguments>
</type>

Where Vendor\Module\Model\Handler\Output is:

namespace  Vendor\Module\Model\Handler;

use Magento\Catalog\Helper\Output as HelperOutput;

class Output
{
    public function productAttribute(HelperOutput $output, string $attributeHtml, array $params): string
    {
        // $params: ['product' => $product, 'attribute' => $attributeName]
        // todo your output handler
        return $attributeHtml;
    }

    public function categoryAttribute(HelperOutput $output, string $attributeHtml, array $params): string
    {
        // $params: ['category' => $category, 'attribute' => $attributeName]
        // todo your output handler
        return $attributeHtml;
    }
}