Version 5 supported

Plugins

Writing a simple plugin: In this tutorial, we add a simple plugin for string fields
Writing a complex plugin: In this tutorial, we'll create a plugin that affects models, queries, and input types
What are plugins?: An overview of how plugins work with the GraphQL schema

Writing a simple plugin

For this example, we want all String fields to have a truncate argument that will limit the length of the string in the response.

Because it applies to fields, we'll want to implement the FieldPlugin interface for this.

namespace MyProject\Plugins;

class Truncator implements FieldPlugin
{
    public function getIdentifier(): string
    {
        return 'truncate';
    }

    public function apply(Field $field, Schema $schema, array $config = [])
    {
        $field->addArg('truncate', 'Int');
    }
}

Now we've added an argument to any field that uses the truncate plugin. This is good, but it really doesn't save us a whole lot of time. The real value here is that the field will automatically apply the truncation.

For that, we'll need to augment our plugin with some afterware.

public function apply(Field $field, Schema $schema, array $config = [])
{
    // Sanity check
    Schema::invariant(
        $field->getType() === 'String',
        'Field %s is not a string. Cannot truncate.',
        $field->getName()
    );

    $field->addArg('truncate', 'Int');
    $field->addResolverAfterware([static::class, 'truncate']);
}

public static function truncate(string $result, array $args): string
{
    $limit = $args['truncate'] ?? null;
    if ($limit) {
        return substr($result, 0, $limit);
    }

    return $result;
}

Let's register the plugin:

SilverStripe\Core\Injector\Injector:
  SilverStripe\GraphQL\Schema\Registry\PluginRegistry:
    constructor:
      - 'MyProject\Plugins\Truncator'

And now we can apply it to any string field we want:

app/_graphql/types.yml

Country:
  name:
    type: String
    plugins:
      truncate: true

Plugins#

Writing a simple plugin#

Further reading#

Writing a simple plugin

Writing a complex plugin

What are plugins?

Plugins

Writing a simple plugin

Further reading