Custom API Hooks ​

Custom API Hooks allow running custom logic when a specified event occurs within your project. There are different types of events to choose from. They are developed using JavaScript / Node.js.

Extension Entrypoint ​

The entrypoint of your hook is the index file inside the src/ folder of your extension package. It exports a register function to register one or more event listeners.

Example of an entrypoint:

export default ({ filter, action }) => {
	filter('items.create', () => {
		console.log('Creating Item!');
	});

	action('items.create', () => {
		console.log('Item created!');
	});
};

export default ({ filter, action }) => {
	filter('items.create', () => {
		console.log('Creating Item!');
	});

	action('items.create', () => {
		console.log('Item created!');
	});
};

Events ​

Your hook can emit on a variety of different events. An event is defined by its type and its name.

There are five event types to choose from:

• Filter
• Action
• Init
• Schedule
• Embed

Use filter hooks when you want the hook to run before the event. Use action hooks when you want the hook to run after the event.

Filter ​

Filter hooks act on the event's payload before the event is emitted. They allow you to check, modify, or cancel an event.

Below is an example of canceling a create event by throwing a Directus error.

import { createError } from '@directus/errors';

const InvalidPayloadError = createError('INVALID_PAYLOAD_ERROR', 'Something went wrong...', 500);

export default ({ filter }) => {
	filter('items.create', async (input) => {
		if (LOGIC_TO_CANCEL_EVENT) {
			throw new InvalidPayloadError();
		}

		return input;
	});
};

import { createError } from '@directus/errors';

const InvalidPayloadError = createError('INVALID_PAYLOAD_ERROR', 'Something went wrong...', 500);

export default ({ filter }) => {
	filter('items.create', async (input) => {
		if (LOGIC_TO_CANCEL_EVENT) {
			throw new InvalidPayloadError();
		}

		return input;
	});
};

The filter register function receives two parameters:

• The event name
• A callback function that is executed whenever the event is emitted.

The callback function itself receives three parameters:

• The modifiable payload
• An event-specific meta object
• A context object

The context object has the following properties:

• database — The current database transaction
• schema — The current API schema in use
• accountability — Information about the current user

Action ​

Action hooks execute after a defined event and receive data related to the event. Use action hooks when you need to automate responses to CRUD events on items or server actions.

The action register function receives two parameters:

• The event name
• A callback function that is executed whenever the event is emitted.

The callback function itself receives two parameters:

• An event-specific meta object
• A context object

The context object has the following properties:

• database — The current database transaction
• schema — The current API schema in use
• accountability — Information about the current user

Init ​

Init hooks execute at a defined point within the life cycle of Directus. Use init hook objects to inject logic into internal services.

The init register function receives two parameters:

• The event name
• A callback function that is executed whenever the event is emitted.

The callback function itself receives one parameter:

• An event-specific meta object

Schedule ​

Schedule hooks execute at certain points in time rather than when Directus performs a specific action. This is supported through node-schedule.

To set up a scheduled event, provide a cron statement as the first parameter to the schedule() function. For example schedule('15 14 1 * *', <...>) (at 14:15 on day-of-month 1) or schedule('5 4 * * sun', <...>) (at 04:05 on Sunday).

Below is an example of registering a schedule hook.

import axios from 'axios';

export default ({ schedule }) => {
	schedule('*/15 * * * *', async () => {
		await axios.post('http://example.com/webhook', { message: 'Another 15 minutes passed...' });
	});
};

import axios from 'axios';

export default ({ schedule }) => {
	schedule('*/15 * * * *', async () => {
		await axios.post('http://example.com/webhook', { message: 'Another 15 minutes passed...' });
	});
};

Embed ​

Inject custom JavaScript or CSS into the <head> and <body> tags within the Data Studio.

The embed register function receives two parameters:

• The position to embed, either head or body.
• The value to embed, either a string or a function that returns a string.

Below is an example of registering embed hooks.

export default ({ embed }, { env }) => {
	// Google Tag Manager Example
	embed(
		'head',
		() => `<!-- Google Tag Manager -->
		<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','${env.GTM_ID}');</script>
		<!-- End Google Tag Manager -->`
	);

	// Sentry Example
	embed(
		'head',
		'<script src="https://browser.sentry-cdn.com/7.21.1/bundle.min.js" integrity="sha384-xOL2QebDu7YNMtC6jW2i5RpQ5RcWOyQMTwrWBiEDezpjjXM7mXhYGz3vze77V91Q" crossorigin="anonymous"></script>'
	);

	embed(
		'body',
		() => `<script>
		Sentry.init({
			dsn: "${env.SENTRY_DSN}" // "https://examplePublicKey@o0.ingest.sentry.io/0",
			release: "my-project-name@${env.npm_package_version}",
			integrations: [new Sentry.BrowserTracing()],

			// We recommend adjusting this value in production, or using tracesSampler
			// for finer control
			tracesSampleRate: 1.0,
		});
		</script>`
	);
};

export default ({ embed }, { env }) => {
	// Google Tag Manager Example
	embed(
		'head',
		() => `<!-- Google Tag Manager -->
		<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','${env.GTM_ID}');</script>
		<!-- End Google Tag Manager -->`
	);

	// Sentry Example
	embed(
		'head',
		'<script src="https://browser.sentry-cdn.com/7.21.1/bundle.min.js" integrity="sha384-xOL2QebDu7YNMtC6jW2i5RpQ5RcWOyQMTwrWBiEDezpjjXM7mXhYGz3vze77V91Q" crossorigin="anonymous"></script>'
	);

	embed(
		'body',
		() => `<script>
		Sentry.init({
			dsn: "${env.SENTRY_DSN}" // "https://examplePublicKey@o0.ingest.sentry.io/0",
			release: "my-project-name@${env.npm_package_version}",
			integrations: [new Sentry.BrowserTracing()],

			// We recommend adjusting this value in production, or using tracesSampler
			// for finer control
			tracesSampleRate: 1.0,
		});
		</script>`
	);
};

Available Events ​

Register Function ​

The register function receives an object containing the type-specific register functions as the first parameter:

• filter — Listen for a filter event
• action — Listen for an action event
• init — Listen for an init event
• schedule — Execute a function at certain points in time
• embed — Inject custom JavaScript or CSS within the Data Studio

The second parameter is a context object with the following properties:

• services — All API internal services
• 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
• logger — Pino instance.
• emitter — Event emitter instance that can be used to emit custom events for other extensions.

Guides ​

Learn how to build hooks with our official guides:

• Use Hooks to Create Stripe Customers
• Use Hooks to Validate Phone Numbers With Twilio