This is early phases of a quickstart guide for creating GraphQL APIs in Totara

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

GraphQL - What is it?

Please read our beginners guide for a quick overview of GraphQL's core concepts: /wiki/spaces/~712020ed0261f15a044ee387ddaa27aaf37f0d/pages/840728681.

Quickstart - Create an Internal Query

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:
- ```
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.

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:
- ```
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:
- ```
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:

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.

<?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.

<?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 - The field being requested 
     * @param $source - In the case, source will be our `item` entity class as it's what's returned from the query resolver
     * @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;
    }
}

Testing Queries

Testing Mutations

TODO:

Screenshots of how to set up the dev_graphql_executor
- Maybe update the main doc for this
Add how to test generally - the below is not enough, need proper guidance
Tidy up steps - they can be much cleaner
👋 Say hello to whoever made it this far and is now just nosey 😂

To test this - Using the developer GraphQL API

GraphQL API Quickstart Guide