The GraphQL Query Language
Features of the GraphQL Query Language
On this page, we'll explore various various features of the GraphQL Query Language
This page is setup as a progression, showing basic usage of GraphQL queries, to more advanced queries and features of the GraphQL query language
Hello World
This is essentially the "hello world" of GraphQL Queries. Here, we are just asking the site for it's Title and URL. Basic settings almost any application built on top of WordPress would need.
GraphiQL Loading...Posts
At the heart of WordPress are Posts. Out of the box, WPGraphQL provides general Schema setup for interacting with posts.
Collection of Posts
Here's an example of querying for a list of posts. By default, you will get 10 posts back.
GraphiQL Loading...Single Post
If you know the ID of a particular Post, you can query for an individual Post, like so:
GraphiQL Loading...PostBy
Sometimes, you may need to fetch an individual Post, but you don't know the ID, but have some other
identifier, such as the slug or the uri.
In that case, we can use a postBy query to fetch using the slug:
Pages
Pages are exposed to WPGraphQL as well, and can be queried in a similar fashion to Posts.
Collections of Pages
GraphiQL Loading...Single Page
If we know the Global ID of a page, we can query for it like so:
GraphiQL Loading...PageBy
Since pages are hierarchical, many pages can have the same slug, so we can't reliably use a slug as
an identifier and thus there's no option to query a page using the slug field in the same way
non-hierarchical Post Types can be queried. However, if we know the URI, we can that as a unique
identifier to fetch an individual Page, together with the idType parameter.
Custom Post Types
WPGraphQL allows for Custom Post Types to be shown in the GraphQL Schema by registering support in the Post Type registry.
There are 3 fields that need to be defined to have a Custom Post Type show in GraphQL:
- show_in_graphql:
trueorfalse - graphql_single_name: camel case string with no punctuation or spaces
- graphql_plural_name: camel case string with no punctuation or spaces
Registering a new Post Type
If you control the code for the Post Type being registered, you can add these three fields to the code that registers your Post Type.
For example, here's an example that registers a Custom Post Type called docs and sets it to show
in GraphQL:
add_action( 'init', function() {
register_post_type( 'docs', [
'show_in_graphql' => true,
'hierarchical' => true,
'graphql_single_name' => 'Document',
'graphql_plural_name' => Documents',
] );
} );Filter Existing Post Type
If you want to expose a Post Type that you don't directly control the registration for, such as a Post Type registerted in a third-party plugin, you can filter the Post Type registration like so:
add_filter( 'register_post_type_args', function( $args, $post_type ) {
if ( 'docs' === $post_type ) {
$args['show_in_graphql'] = true;
$args['graphql_single_name'] = 'Document';
$args['graphql_plural_name'] = 'Documents';
}
return $args;
}, 10, 2 );