Examples given is of a plugin named local_todo which is the plugin todo in the local directory.

Internal

Let’s create the schema

• Create a webapi directory in your plugin root

• Under the webapi create a ajax directory

• Create a schema.graphqls file under the ajax directory

• In schema.graphqls let’s define the todo_item type by adding the following:

  • Code Block
    language graphql
    type local_todo_item { id: core_id title: String completed_at: core_date }

  • This adds a new type with id, title and completed_at which we will have access to when using this type.

Now we’ll create the query

We’ll start off our APIs with creating a query to retrieve a list of the type todo_item.

• In schema.graphqls define the result we’ll get back from the query by defining the following type:

  • Code Block
    type local_todo_items_result { items: [local_todo_item!]! }

  • Notice here we’ve used ! in two places. This indicates the field is non-nullable. We’ve used this here to say that we always expect an array, by putting the exclamation mark on the outside of the array [...]!. We also used to to say that the elements of the array cannot be null [my_type!].

• Now we have the result defined, let’s define the query. We do this by extending the type Query and adding our query into it. Let’s do this:

  • Code Block
    extend type Query { local_todo_items: local_todo_items_result! }

  • This defines that the query local_todo_items should return the local_todo_items_result type we defined earlier

Creating the persisted query

The persisted query is a definition of the query for the frontend component to import. We name this file the query name, minus the component name of the plugin we’re working with.

Persisted queries use .graphql instead of the .graphqls we used previously for the schema file.

• Create the persisted query file in the webapi/ajax/items.graphql with the following:

  • Code Block
    language graphql
    query local_todo_items { items { id title completed_at } }

Create the backend

Now we need to create the PHP backend to handle the query.

• First we’ll create the directory for the query resolver by creating the following directory /server/local/todo/classes/webapi/resolver/query

• Now let’s create the query resolver class, items.php in the directory we just created.

  • Code Block
    language php
    <?php namespace local_todo\webapi\resolver\query; use core\webapi\execution_context; use core\webapi\query_resolver; use local_todo\entity\item; class items extends query_resolver { /** * @inheritDoc * @throws \coding_exception */ public static function resolve(array $args, execution_context $ec) { global $USER; $items = item::repository() ->where('user_id', $USER->id) ->order_by('id') ->get(); return ['items' => $items]; } }

  • In this file we’ve defined the query resolve and we’re using the ORM of local_todo to return a list of items.

• Now we create the type resolver directory /server/local/todo/classes/webapi/resolver/type/ and the type resolver for item item.php in the directory.

  • Code Block
    language php
    <?php namespace local_todo\webapi\resolver\type; use core\webapi\execution_context; use core\webapi\type_resolver; class item extends type_resolver { /** * @param string $field * @param $source * @param array $args * @param execution_context $ec * @return mixed|void */ public static function resolve(string $field, $source, array $args, execution_context $ec) { return $source->$field; } }

To test this - Using the developer GraphQL API