Create helper functions for extending queries and mutations

[CodeProKid]

I think it would be good to have some helper functions that make it easier for developers to extend WPGraphQL. Something similar to register_rest_route(). This would help lower the barrier to entry for the community, and would also provide developers with a consistent way to extend the plugin, which would make backwards compatibility easier for us down the line.

This is just a stubbed issue, I have some more in depth ideas for this that I'll share when I get a moment, open to feedback from anyone else as well though.

[jasonbahl]

@CodeProKid ya, I'd love to see what ideas you have. I think this would definitely be a good thing to have some nice register_* functions (and other general "access functions / template tags") to make it easier to hook into the schema.

Off the top of my head, here are some that I can think of that might be good:

register_graphql_field

This would allow someone to add a field to any type in the Schema.

Might look like register_graphql_field( $types $args )

Where $type is the Type (or array of Types?) in the Schema to add the field to, and $args would include the name of the field, the description, field args, and the resolver for the function.

$args = [
  'name' => 'myCustomField',
  'description' => __( 'My Custom Field for Posts', 'my-plugin' ),
  'resolve' => function( $post, $args, $context, $info  ) {
      return get_post_meta( $post->ID, 'my_custom_field_key', true );
  }
];

register_graphql_field( [ 'Post', $args ] );

register_graphql_type

This one I think needs a little more thought. . .because there are different Types that can be registered, so not sure if we want a different function for each, like register_graphql_enum_type and register_graphql_object_type or something like that? Or if we can make register_graphql_type work for all with the proper input $args. . .

register_graphql_mutation_field / register_graphql_mutation_type?

Not sure what this would look like, but might be helpful. . .

graphql_wrap_resolver( $fieldName, $type, $callback )

Not sure exactly how this should look, but I think it would be good to have some function like this that allows folks to add granular control over specific fields. . .

For example, if I wanted to hide just privateField on the postObject, I could do something like:

graphql_wrap_resolver( 'privateField', 'Post', function( $source, $args, $context, $info, $defaultResolver ) {
    if ( ! current_user_can( 'seePrivateFields' ) {
        throw new \Exception( __( 'Sorry, you cannot see private fields', 'wp-graphql' ) );
    }
    return $defaultResolver;
});

we could even potentially have other pre-made ones, like: graphql_require_authentication( $fieldName, $type ) that is potentially implemented something to this tune. . .(totally pseudo code):

function graphql_require_auth( $fieldName, $type ) {
  return graphql_wrap_resolver( $fieldName, $type, 'requireAuthCallback' );
}

function requireAuthCallback( $source, $args, $context, $info, $defaultResolver ) {
  if ( ! wp_get_current_user() ) {
    throw new \Exception( __( 'You must be logged in to do this', 'wp-graphql' ) );
  }
  return $defaultResolver;
}

[cr101]

Would it be possible to add my CPTs and their custom fields to the Schema and then run a query like below?

query {
	author(id: 4452) {
		id
		name,
		books(isbn: a45459) {
			title,
			isbn
		}
	}
}

I'm using ACF but I've registered all my custom post types and the custom fields for each CPT via PHP instead of the ACF UI. All my CPTs are linked to each other via bidirectional relationships.

[jasonbahl]

Hey @cr101 I’m afk but will get you more details when I get to a computer. You can search closed issues though and you should be able to find info on registering custom post types and adding fields to the types in your schema.

[cr101]

Hi @jasonbahl

I’m afk but will get you more details when I get to a computer.

I'd love to see an example, thank you. I had a look on the Wiki but I couldn't find any examples.

[jasonbahl]

closing this and tracking on #327