Not loading shema in IDE

[martin-braun]

Once I activate the plugin, the wp_graphql IDE won't load its schema.

/index.php?gql:1 Failed to load resource: the server responded with a status of 500 (Internal Server Error)
invariant.mjs:6 Uncaught (in promise) Error: Invalid or incomplete introspection result. Ensure that you are passing "data" property of introspection response and no "errors" was returned alongside: { status: 500 }
    at r (invariant.mjs:6)
    at r (buildClientSchema.mjs:27)
    at App.js:181

WordPress 5.6
WP GraphQL 1.0.3

[lmartins]

Same here. Considering that it has been several months since this was opened, I wonder if this plugin is still the way to go to expose meta fields to GraphQL.

[martin-braun]

Same here. Considering that it has been several months since this was opened, I wonder if this plugin is still the way to go to expose meta fields to GraphQL.

@lmartins Unfortunately, it's not. Build your own meta fields using ACF and expose them using WPGraphQL for ACF.

[lmartins]

Same here. Considering that it has been several months since this was opened, I wonder if this plugin is still the way to go to expose meta fields to GraphQL.

@lmartins Unfortunately, it's not. Build your own meta fields using ACF and expose them using WPGraphQL for ACF.

I've used that and works great. However in this case I was looking to pull meta fields created by WordPress internal APIs that do not go through ACF.

[martin-braun]

I've used that and works great. However in this case I was looking to pull meta fields created by WordPress internal APIs that do not go through ACF.

I just checked my code, because I had the same problem. I ended up registering the meta fields by myself like so:

add_action( 'graphql_register_types', function() {

	$metaFields = [
		'course' => [
			'announcement' => 'String',
			'duration_info' => 'String',
			'level' => 'String',
			'price' => 'String',
			'sale_price' => 'String',
			'sale_price_dates' => 'String',
			'sale_price_dates_end' => 'String',
			'sale_price_dates_start' => 'String',
			'skill_level' => 'String',
			'status' => 'String',
			'status_dates' => 'String',
			'status_dates_end' => 'String',
			'status_dates_start' => 'String',
		]
	];

	foreach ( $metaFields as $object_name => $fields ) {

		foreach ( $fields as $field_name => $field_type ) {
			
			$field_name_key = $field_name;
			$field_api_name = $object_name . '_' . $field_name;
			$field_api_name = str_replace( '_', '', ucwords( $field_api_name, '_' ) );
			register_graphql_field( $object_name, $field_api_name, [
					'type' => $field_type,
					'resolve' => function( $post ) use( $field_name_key ) {
						return get_post_meta( $post->ID, $field_name_key, true );
					}
			]);

		}

	}

} );

This is copied from my past project, it was exposing meta fields of MasterStudy, a theme / plugin collection for WordPress.
In the example the first level of $metaFields is the post_type, while the second level is the name of the post_meta field. The $field_api_name will be "CourseAnnouncement" in its first iteration.

You can see how the GraphQL fields are registered and a resolver is added that will just resolve the value by calling get_post_meta. This will not provide neat stuff like ordering and filtering, I think, it will just provide the fields in your model.

I have also code written to add ordering (orderby) and filtering (where) for ACF. It's not compatible with the sample above as it's for other fields, but maybe you can convert it so it adds the functionality to your fields, too:

// ORDERBY:

add_filter( 'graphql_PostObjectsConnectionOrderbyEnum_values', function( $values ) {

	$values['RELEVANCE'] = [
		'value' => 'relevance' // add custom meta fields as orderby options
	];

	return $values;

} );

add_filter( 'graphql_post_object_connection_query_args', function( $query_args, $source, $input ) {

	if ( isset( $input['where']['orderby'] ) && is_array( $input['where']['orderby'] ) ) {

		foreach( $input['where']['orderby'] as $orderby ) {

			if ( 
				$orderby['field'] === 'relevance' 
			) {
				$query_args['meta_key'] = $orderby['field'];
				$query_args['orderby'] = 'meta_value_num';
				$query_args['order'] = $orderby['order'];
			}

		}

	}

	return $query_args;

}, 10, 3);

// WHERE:

add_action( 'graphql_register_types', function () {

	$root_query_type = 'RootQuery';
	$course_category_type = 'CourseCategory';
	$course_type = "Course";

	register_graphql_field( $course_category_type . 'To' . $course_type . 'ConnectionWhereArgs', 'relevance_gte', [
		'type' => 'Number',
	] );

	register_graphql_field( $root_query_type . 'To' . $course_type . 'ConnectionWhereArgs', 'relevance_gte', [
		'type' => 'Number',
	] );

	register_graphql_field( $root_query_type . 'To' . $course_type . 'ConnectionWhereArgs', 'tags_like', [
		'type' => 'String',
	] );
	
} );

add_filter( 'graphql_post_object_connection_query_args', function ( $query_args, $source, $args, $context, $info ) {

	$meta_query = [];

	if ( isset( $args['where']['relevance_gte'] ) ) {

		$meta_query['tags'][] = [
			'key' => 'relevance',
			'value' => $args['where']['relevance_gte'],
			'compare' => '>='
		];

	}

	if ( isset( $args['where']['tags_like'] ) ) {
		$tags_filter_arr = explode( ';', $args['where']['tags_like'] );

		$meta_query['tags'] = [
			'relation' => 'OR'
		];
		foreach ( $tags_filter_arr as $tags_filter_arr_item ) {
			if($tags_filter_arr_item) {
				$meta_query['tags'][] = [
					'key' => 'tags',
					'value' => str_replace( ' ', '', $tags_filter_arr_item ) . ';',
					'compare' => 'LIKE'
				];
			}
		}
	}

	$query_args['meta_query'] = $meta_query;
	return $query_args;
}, 10, 5 );

You can see how it's programmed only for two custom field called "relevance" and "tags" and a specific operation "gte" (greater than equals) for the "relevance" as well as a like comparer for the "tags" field. It might give you help to understand in what direction you have to move to get this stuff for your custom fields. You would program a lot of stuff to give your fields everything that is possible, so think about what meta operations you really need.

If you don't need order or filter operations on the fields, consider yourself lucky, because you won't need to progress the latter example.

Good luck!