@cloudflare/actors SDK library for Durable Objects now in beta

The new @cloudflare/actors ↗ library is now in beta!

The @cloudflare/actors library is a new SDK for Durable Objects and provides a powerful set of abstractions for building real-time, interactive, and multiplayer applications on top of Durable Objects. With beta usage and feedback, @cloudflare/actors will become the recommended way to build on Durable Objects and draws upon Cloudflare's experience building products/features on Durable Objects.

The name "actors" originates from the actor programming model, which closely ties to how Durable Objects are modelled.

The @cloudflare/actors library includes:

• Storage helpers for querying embeddeded, per-object SQLite storage
• Storage helpers for managing SQL schema migrations
• Alarm helpers for scheduling multiple alarms provided a date, delay in seconds, or cron expression
• Actor class for using Durable Objects with a defined pattern
• Durable Objects Workers API ↗ is always available for your application as needed

Storage and alarm helper methods can be combined with any Javascript class ↗ that defines your Durable Object, i.e, ones that extend DurableObject including the Actor class.

import { Storage } from "@cloudflare/actors/storage";

export class ChatRoom extends DurableObject<Env> {
    storage: Storage;

    constructor(ctx: DurableObjectState, env: Env) {
        super(ctx, env)
        this.storage = new Storage(ctx.storage);
        this.storage.migrations = [{
            idMonotonicInc: 1,
            description: "Create users table",
            sql: "CREATE TABLE IF NOT EXISTS users (id INTEGER PRIMARY KEY)"
        }]
    }
    async fetch(request: Request): Promise<Response> {
        // Run migrations before executing SQL query
        await this.storage.runMigrations();

        // Query with SQL template
        let userId = new URL(request.url).searchParams.get("userId");
        const query = this.storage.sql`SELECT * FROM users WHERE id = ${userId};`
        return new Response(`${JSON.stringify(query)}`);
    }
}

@cloudflare/actors library introduces the Actor class pattern. Actor lets you access Durable Objects without writing the Worker that communicates with your Durable Object (the Worker is created for you). By default, requests are routed to a Durable Object named "default".

export class MyActor extends Actor<Env> {
    async fetch(request: Request): Promise<Response> {
        return new Response('Hello, World!')
    }
}

export default handler(MyActor);

You can route to different Durable Objects by name within your Actor class using nameFromRequest ↗.

export class MyActor extends Actor<Env> {
    static nameFromRequest(request: Request): string {
        let url = new URL(request.url);
        return url.searchParams.get("userId") ?? "foo";
    }

    async fetch(request: Request): Promise<Response> {
        return new Response(`Actor identifier (Durable Object name): ${this.identifier}`);
    }
}

export default handler(MyActor);

For more examples, check out the library README ↗. @cloudflare/actors library is a place for more helpers and built-in patterns, like retry handling and Websocket-based applications, to reduce development overhead for common Durable Objects functionality. Please share feedback and what more you would like to see on our Discord channel ↗.