🔒 WP GraphQL Lock

This plugin enables query locking for WPGraphQL by implementing persisted GraphQL queries.

Persisted GraphQL queries allow a GraphQL client to optimistically send a hash of the query instead of the full query; if the server has seen the query before, it can satisfy the request.

Once the server knowns all the possible queries the plugin can lock it down disallowing any unwanted queries that are possibly malicious. This can greatly improve the server security and can even protect against unpatched vulnerabilities in some cases.

Alternatively you can pre-generate the query IDs from your client source code with the GraphQL Code Generator plugin and load the IDs with the graphql_lock_load_query filter.

In addition to enabling query locking this saves network overhead and makes it possible to move to GET requests instead of POST. The primary benefit of GET requests is that they can be easily cached at the edge (e.g., with Varnish, nginx etc.).

This plugin requires WPGraphQL 0.2.0 or newer.

Compatibility

Apollo Client provides an easy implementation of persisted queries:

https://github.com/apollographql/apollo-link-persisted-queries#automatic-persisted-queries

This plugin aims to be compatible with that implementation, but will work with any client that sends a queryId alongside the query. Make sure your client also sends operationName with the optimistic request.

Implementation

When the client provides a query hash or ID, that query will be persisted in a custom post type. By default, this post type will be visible in the dashboard only to admins.

Query IDs are case-insensitive (i.e., MyQuery and myquery are equivalent).

Installation

If you use composer you can install it from packagist

composer require valu/wp-graphql-lock

Otherwise you can clone it from Github to your plugins using the stable branch

cd wp-content/plugins
git clone --branch stable https://github.com/valu-digital/wp-graphql-lock.git

Filters

graphql_lock_load_query

• Load the queries from a custom location
• The query ID is passed as the second parameter

Example:

add_filter( 'graphql_lock_load_query', function( string $query, string $query_id ) {
    $queries = json_decode( file_get_contents( __DIR__ . '/.persisted-query-ids/server.json' ), true );
    return $queries[ $query_id ] ?? null;
}, 10, 2 );

Note: You should prefer using hidden directories / files to avoid exposing the lock file via your webserver.

graphql_lock_post_type

• Default: 'graphql_query'
• The custom post type used to persist queries. If empty, queries will not be persisted.

graphql_lock_show_in_graphql

• Default: false
• Whether the custom post type will itself be exposed via GraphQL. Enabling allows insight into which queries are persisted.

query PersistedQueryQuery {
  persistedQueries {
    nodes {
      id
      title
      content(format: RAW)
    }
  }
}

If you'd like to further customize the custom post type, filter register_post_type_args.

Lock mode

When it's active no new queries can be saved and only the saved ones can be used. This can greatly improve security as attackers cannot send arbitrary queries to the endpoint.

Lock mode can be activated by setting graphql_lock_locked option to true:

update_option( 'graphql_lock_locked', true );

add_filter( 'option_graphql_lock_locked', function() {
    return 'production' === WP_ENV;
}, 10 , 1 );

Settings

There's a settings screen for managing the option

Acknowledgements

This plugin is based on the Quartz persisted Queries plugin.

Contributing

Read CONTRIBUTING.md