README

hyva-themes/magento2-graphql-view-model

This module adds a GraphQL ViewModel to allow GraphQL queries and mutations to be customized before they are rendered in the output.

Compatible with Magento 2.3.4 and higher.

What does it do?

It provides:

• \Hyva\GraphqlViewModel\ViewModel\GraphqlViewModel, to be accessed via the view model registry (or injected via Layout XML).
• \Hyva\GraphqlViewModel\Model\GraphqlQueryEditor which can be used to add fields and arguments to GraphQL queries.
• The event hyva_graphql_render_before_ + query identifier Event observers receive the query string and can manipulate it with the GraphqlQueryEditor

Usage

In .phtml templates, to make queries customizable, wrap them with the GraphqlViewModel::query() method:

<?= $gqlViewModel->query("product_list_query", "
products(filter: {} pageSize: 20) {
  items {
    {$type}_products {
        sku
        id
        small_image {
          url
        }
    }
  }
}", ['type' => $type])
?>

The first argument is the event name suffix.
The second argument is the query or mutation as a string.
The third argument is optional and - if specified - will be merged into the event arguments.

In the above example the full event name would be hyva_graphql_render_before_product_list_query

To manipulate a query in an event observer, the GraphqlQueryEditor can be used:

public function execute(Observer $event)
{
    $gqlEditor = new GraphqlQueryEditor(); // or use dependency injection
    
    $queryString = $event->getData('gql_container')->getData('query');
    $linkType  = $event->getData('type');
    $path  = ['products', 'items', ($linkType ? "{$linkType}_products" : 'products'), 'small_image'];
    
    // add a single field to a result object
    $queryString = $gqlEditor->addFieldIn($queryString, $path, 'url_webp');
    
    // add multiple fields to a result object
    $queryString = $gqlEditor->addFieldIn($queryString, ['products', 'items', 'products', 'image'], 'label url_webp');
    
    // add a query argument
    $queryString = $gqlEditor->addArgumentIn($queryString, ['products', 'filter', 'name'], 'match', 'Tank');
    $queryString = $gqlEditor->addArgumentIn($queryString, ['products'], 'pageSize', 2);
    
    // set updated query back on container
    $event->getData('gql_container')->setData('query', $queryString);
}

The result of the example method call

$gqlEditor->addFieldIn($queryString, ['products', 'items', 'products', 'small_image'], 'label url_webp')

is that in the query the fields at the specified path are set:

products {
  items {
    products {
      small_image {
        label
        url_webp
      }
    }
  }
}

Both the addFieldIn and the addArgumentIn methods are idempotent, so if the specified values already exist in the query string they are not changed.

The addArgumentIn method can be used to add new arguments to queries or mutations, or to overwrite values of existing arguments.

For more examples including inline fragments please have a look at the \Hyva\GraphqlViewModel\Model\GraphqlQueryEditorTest class.

Installation

1. Install via composer

   composer config repositories.hyva-themes/magento2-graphql-view-model git git@github.com:hyva-themes/magento2-graphql-view-model.git
   composer require hyva-themes/magento2-graphql-view-model
   

2. Enable module

   bin/magento module:enable Hyva_GraphqlViewModel
   

Configuration

No configuration needed.

License

The BSD-3-Clause License. Please see License File for more information.