Version 5
supported
Plugins
- What are plugins?
- An overview of how plugins work with the GraphQL schema
- 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
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 App\GraphQL\Plugin;
use SilverStripe\GraphQL\Schema\Field\Field;
use SilverStripe\GraphQL\Schema\Interfaces\FieldPlugin;
use SilverStripe\GraphQL\Schema\Schema;
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.
namespace App\GraphQL\Plugin;
use SilverStripe\GraphQL\Schema\Field\Field;
use SilverStripe\GraphQL\Schema\Interfaces\FieldPlugin;
use SilverStripe\GraphQL\Schema\Schema;
class Truncator implements FieldPlugin
{
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:
- 'App\GraphQL\Plugin\Truncator'
And now we can apply it to any string field we want:
# app/_graphql/types.yml
Country:
name:
type: String
plugins:
truncate: true