y-durableobjects

The y-durableobjects library is designed to facilitate real-time collaboration in the Cloudflare Workers environment using Yjs and Durable Objects. It provides a straightforward way to integrate Yjs for decentralized, scalable real-time editing features.

Requirements

• Hono version 4.3 or higher is required.

Installation

To use y-durableobjects, you need to install the package along with hono, as it is a peer dependency.

npm install y-durableobjects hono

or using yarn:

yarn add y-durableobjects hono

or pnpm:

pnpm add y-durableobjects hono

Configuration for Durable Objects

To properly utilize Durable Objects, you need to configure bindings in your wrangler.toml file. This involves specifying the name of the Durable Object binding and the class name that represents your Durable Object. For detailed instructions on how to set up your wrangler.toml for Durable Objects, including setting up environment variables and additional resources, refer to Cloudflare's Durable Objects documentation.

This configuration ensures that your Cloudflare Worker can correctly instantiate and interact with Durable Objects, allowing y-durableobjects to manage real-time collaboration sessions.

name = "your-worker-name"
main = "src/index.ts"
compatibility_date = "2024-04-05"

account_id = "your-account-id"
workers_dev = true

# Durable Objects binding
[durable_objects]
bindings = [
  { name = "Y_DURABLE_OBJECTS", class_name = "YDurableObjects" }
]

# Durable Objects migrations
[[migrations]]
tag = "v1"
new_classes = ["YDurableObjects"]

Usage

With Hono shorthand

import { Hono } from "hono";
import { YDurableObjects, yRoute } from "y-durableobjects";

type Bindings = {
  Y_DURABLE_OBJECTS: DurableObjectNamespace<YDurableObjects<Env>>;
};

type Env = {
  Bindings: Bindings;
};

const app = new Hono<Env>();

const route = app.route(
  "/editor",
  yRoute<Env>((env) => env.Y_DURABLE_OBJECTS),
);

export default route;
export type AppType = typeof route;
export { YDurableObjects };

Without the shorthand

The following example demonstrates how to integrate Hono RPC with y-durableobjects. Note that WebSocket connections must be handled via fetch due to the current limitations of JS RPC (see Cloudflare issue):

import { Hono } from "hono";
import { YDurableObjects, type YDurableObjectsAppType } from "y-durableobjects";
import { upgrade } from "y-durableobjects/helpers/upgrade";

type Bindings = {
  Y_DURABLE_OBJECTS: DurableObjectNamespace<YDurableObjects<Env>>;
};

type Env = {
  Bindings: Bindings;
};

const app = new Hono<Env>();
app.get("/editor/:id", upgrade(), async (c) => {
  const id = c.env.Y_DURABLE_OBJECTS.idFromName(c.req.param("id"));
  const stub = c.env.Y_DURABLE_OBJECTS.get(id);

  const url = new URL("/", c.req.url);
  const client = hc<YDurableObjectsAppType>(url.toString(), {
    fetch: stub.fetch.bind(stub),
  });

  const res = await client.rooms[":id"].$get(
    { param: { id: c.req.param("id") } },
    { init: { headers: c.req.raw.headers } },
  );

  return new Response(null, {
    webSocket: res.webSocket,
    status: res.status,
    statusText: res.statusText,
  });
});

export default app;
export type AppType = typeof app;
export { YDurableObjects };

JS RPC support

y-durableobjects supports JS RPC for fetching and updating YDocs. Below are examples of how to use the getYDoc and updateYDoc interfaces.

getYDoc

This API fetches the state of the YDoc within a Durable Object.

Example usage in Hono:

import { Hono } from "hono";
import { YDurableObjects } from "y-durableobjects";
import { fromUint8Array } from "js-base64";

type Bindings = {
  Y_DURABLE_OBJECTS: DurableObjectNamespace<YDurableObjects<Env>>;
};

type Env = {
  Bindings: Bindings;
};

const app = new Hono<Env>();

app.get("/rooms/:id/state", async (c) => {
  const roomId = c.req.param("id");
  const id = c.env.Y_DURABLE_OBJECTS.idFromName(roomId);
  const stub = c.env.Y_DURABLE_OBJECTS.get(id);

  const doc = await stub.getYDoc();
  const base64 = fromUint8Array(doc);

  return c.json({ doc: base64 }, 200);
});

export default app;
export { YDurableObjects };

updateYDoc

This API updates the state of the YDoc within a Durable Object.

Example usage in Hono:

import { Hono } from "hono";
import { YDurableObjects } from "y-durableobjects";

type Bindings = {
  Y_DURABLE_OBJECTS: DurableObjectNamespace<YDurableObjects<Env>>;
};

type Env = {
  Bindings: Bindings;
};

const app = new Hono<Env>();

app.post("/rooms/:id/update", async (c) => {
  const roomId = c.req.param("id");
  const id = c.env.Y_DURABLE_OBJECTS.idFromName(roomId);
  const stub = c.env.Y_DURABLE_OBJECTS.get(id);

  const buffer = await c.req.arrayBuffer();
  const update = new Uint8Array(buffer);

  await stub.updateYDoc(update);

  return c.json(null, 200);
});

export default app;
export { YDurableObjects };

Extending with JS RPC

By supporting JS RPC, y-durableobjects allows for advanced operations through extensions. You can manipulate the protected fields for custom functionality:

Example:

import { applyUpdate, encodeStateAsUpdate } from "yjs";
import { YDurableObjects } from "y-durableobjects";

export class CustomDurableObject extends YDurableObjects {
  async customMethod() {
    // Access and manipulate the YDoc state
    const update = new Uint8Array([
      /* some update data */
    ]);
    this.doc.update(update);
    await this.cleanup();
  }
}

Hono RPC support for ClientSide

• Utilizes Hono's WebSocket Helper, making the $ws method available in hono/client for WebSocket communications.
  • For more information on server and client setup, see the Hono WebSocket Helper documentation.

Server Implementation

Using shorthand

import { Hono } from "hono";
import { YDurableObjects, yRoute } from "y-durableobjects";

type Bindings = {
  Y_DURABLE_OBJECTS: DurableObjectNamespace<YDurableObjects<Env>>;
};

type Env = {
  Bindings: Bindings;
};

const app = new Hono<Env>();
const route = app.route(
  "/editor",
  yRoute<Env>((env) => env.Y_DURABLE_OBJECTS),
);

export default route;
export type AppType = typeof route;
export { YDurableObjects };

Without shorthand

import { Hono } from "hono";
import { YDurableObjects, YDurableObjectsAppType } from "y-durableobjects";
import { upgrade } from "y-durableobjects/helpers/upgrade";

type Bindings = {
  Y_DURABLE_OBJECTS: DurableObjectNamespace<YDurableObjects<Env>>;
};

type Env = {
  Bindings: Bindings;
};

const app = new Hono<Env>();
app.get("/editor/:id", upgrade(), async (c) => {
  const id = c.env.Y_DURABLE_OBJECTS.idFromName(c.req.param("id"));
  const stub = c.env.Y_DURABLE_OBJECTS.get(id);

  const url = new URL("/", c.req.url);
  const client = hc<YDurableObjectsAppType>(url, {
    fetch: stub.fetch.bind(stub),
  });

  const res = await client.rooms[":id"].$get(
    { param: { id: c.req.param("id") } },
    { init: { headers: c.req.raw.headers } },
  );

  return new Response(null, {
    webSocket: res.webSocket,
    status: res.status,
    statusText: res.statusText,
  });
});

export default app;
export type AppType = typeof app;
export { YDurableObjects };

Client Implementation

To utilize Hono RPC on the client side, you can create a typed client using hc from hono/client:

import { hc } from "hono/client";
import type { AppType } from "./server"; // Adjust the import path as needed

const API_URL = "http://localhost:8787";

export const client = hc<AppType>(API_URL);
const ws = client.editor[":id"].$ws({ param: { id: "example" } });
//    ^?const ws: WebSocket

Troubleshooting

Cloudflare Env Type Collision

If you encounter TypeScript errors related to Cloudflare.Env type being empty or undefined, this is likely due to a type collision issue.

Problem

The issue occurs because y-durableobjects requires @cloudflare/workers-types as a peer dependency, which can create an empty Cloudflare.Env interface in node_modules. This empty interface overwrites your project's custom environment types and causes the worker-configuration.d.ts file generated from wrangler types to be ignored.

Recommended Approach

Starting with Wrangler v3, the wrangler types command is the recommended approach for generating TypeScript types for Cloudflare Workers. This command generates types based on your project's configuration, compatibility date, and bindings, ensuring accurate and up-to-date type definitions.

To generate types for your project:

wrangler types

This will create a worker-configuration.d.ts file (or similar) with the proper type definitions for your Cloudflare Workers environment.

Solution

If Cloudflare.Env remains empty even after upgrading to the latest y-durableobjects version, follow these steps:

1. Check for remaining dependencies:

   pnpm why @cloudflare/workers-types

2. Clean install dependencies:

   # Delete lock files and node_modules
   rm -rf node_modules pnpm-lock.yaml
   # Reinstall dependencies
   pnpm install

3. Verify the fix: Run pnpm why @cloudflare/workers-types again. If it returns nothing, the issue is resolved.

This issue was addressed in PR #62, but residual @cloudflare/workers-types dependencies from wrangler may still remain in your lock file until you perform a clean install.