Custom API Hooks

Custom API Hooks allow running custom logic when a specified event occurs within your project. They can be registered as either "blocking" or immediate.

1. Create a Hook File

Custom hooks are dynamically loaded from within your extensions folder. By default this directory is located at /extensions, but it can be configured within your project's env file to be located anywhere.

Default Standalone Hook Location

/extensions/hooks/<hook-id>/index.js

2. Define the Event

Next, you will want to define your event. You can trigger your custom hook with any of the platform's many API events. System events are referenced with the format:

<scope>.<action>(.<before>)
// eg: items.create
// eg: files.create
// eg: collections.*
// eg: users.update.before

Scope

The scope determines the API endpoint that is triggered. The * wildcard can also be used to include all scopes.

System Scope

Currently all system tables are available as event scopes except for directus_migrations and directus_sessions, which don't have relevant endpoints or services.

Action

Defines the triggering operation within the specified context (see chart below). The * wildcard can also be used to include all actions available to the scope.

Before

Many scopes (see chart below) support an optional .before suffix for running a blocking hook prior to the event being fired. This allows you to check and/or modify the event's payload before it is processed.

• items.create.before (Blocking)
• items.create (Non Blocking, also called 'after' implicitly)

This also allows you to cancel an event based on the logic within the hook. Below is an example of how you can cancel a create event by throwing a standard Directus exception.

module.exports = function registerHook({ exceptions }) {
	const { InvalidPayloadException } = exceptions;

	return {
		'items.create.before': async function (input) {
			if (LOGIC_TO_CANCEL_EVENT) {
				throw new InvalidPayloadException(WHAT_IS_WRONG);
			}

			return input;
		},
	};
};

Event Format Options

Scope	Actions	Before
server	start and stop	Optional
init		Optional
routes.init	before and after	No
routes.custom.init	before and after	No
middlewares.init	before and after	No
request	not_found	No
response		No†
error		No
auth	login, logout† and refresh†	Optional
items	create, update and delete	Optional
activity	create, update and delete	Optional
collections	create, update and delete	Optional
fields	create, update and delete	Optional
files	create, update and delete	Optional
folders	create, update and delete	Optional
permissions	create, update and delete	Optional
presets	create, update and delete	Optional
relations	create, update and delete	Optional
revisions	create, update and delete	Optional
roles	create, update and delete	Optional
settings	create, update and delete	Optional
users	create, update and delete	Optional
webhooks	create, update and delete	Optional

† Feature Coming Soon

3. Register your Hook

Each custom hook is registered to its event scope using a function with the following format:

module.exports = function registerHook() {
	return {
		'items.create': function () {
			axios.post('http://example.com/webhook');
		},
	};
};

4. Develop your Custom Hook

Register Function

The register function (eg: module.exports = function registerHook()) must return an object where the key is the event, and the value is the handler function itself.

The registerHook function receives a context parameter with the following properties:

• services — All API internal services
• exceptions — API exception objects that can be used for throwing "proper" errors
• database — Knex instance that is connected to the current database
• getSchema — Async function that reads the full available schema for use in services
• env — Parsed environment variables

Event Handler Function

The event handler function (eg: 'items.create': function()) receives a context parameter with the following properties:

• event — Full event string
• accountability — Information about the current user
• collection — Collection that is being modified
• item — Primary key(s) of the item(s) being modified
• action — Action that is performed
• payload — Payload of the request
• schema - The current API schema in use
• database - Current database transaction

Auth

The auth hooks have the following context properties:

• event — Full event string
• accountability — Information about the current user
• action — Action that is performed
• payload — Payload of the request
• schema - The current API schema in use
• status - One of pending, success, fail
• user - ID of the user that tried logging in/has logged in

5. Restart the API

To deploy your hook, simply restart the API by running:

npx directus start

Full Example:

// extensions/hooks/sync-with-external/index.js

module.exports = function registerHook({ services, exceptions }) {
	const { ServiceUnavailableException, ForbiddenException } = exceptions;

	return {
		// Force everything to be admin-only at all times
		'items.*': async function ({ item, accountability }) {
			if (accountability.admin !== true) throw new ForbiddenException();
		},
		// Sync with external recipes service, cancel creation on failure
		'items.create.before': async function (input, { collection }) {
			if (collection !== 'recipes') return input;

			try {
				await axios.post('https://example.com/recipes', input);
			} catch (error) {
				throw new ServiceUnavailableException(error);
			}

			input[0].syncedWithExample = true;

			return input;
		},
	};
};