Decentralized Document Network (DDNet)

Decentralized Document Network (DDNet) is a cutting-edge, decentralized network designed for secure storage and access of documents. It aims to address the inherent challenges of centralized document storage systems, namely access control and single points of failure, by providing a robust, decentralized alternative powered by cryptographic techniques.

Features

• Decentralized: DDNet is a decentralized network that enables users to store and access documents in a secure, distributed manner.
• Secure: DDNet uses cryptographic techniques to ensure that documents are stored and accessed securely.
• Private: DDNet uses a decentralized architecture that ensures data ownership, privacy, and the freedom to collaborate seamlessly.
• Local-first: DDNet is a local-first network that enables users to store and access documents locally.
• CRDT-based: DDNet uses Conflict-free Replicated Data Types (CRDTs) to ensure that documents are replicated across the network in a consistent manner.

Getting Started

Installation

# Using npm
$ npm install @describble/ddnet

# Using pnpm
$ pnpm install @describble/ddnet

# Using yarn
$ yarn add @describble/ddnet

Usage

We have divided the usage examples into smaller chunks, each demonstrating a specific aspect of DDNet.

KeyManager

The KeyManager class handles the generation and storage of cryptographic keys for users. You pass the store-name to it as a string. This is the name of the IndexedDB store where keys are saved.

import { KeyManager } from '@describble/ddnet';

const keyManager = new KeyManager('store-name');

SessionManager

SessionManager is responsible for managing user's sessions. It takes an instance of KeyManager as a parameter to manage cryptographic keys. You can also optionally pass an instance of ServiceWorkerCache to cache sessions in the browser.

import { SessionManager, KeyManager, ServiceWorkerCache } from '@describble/ddnet';

const sessionManager = new SessionManager(
  new KeyManager('store-name'),
  new ServiceWorkerCache(myServiceWorkerInstance) // optional session caching
);

NetworkAdapter

DDnet requires a NetworkAdapter to communicate with the signaling server. You can use the WebSocketNetworkAdapter class for this. Pass the URL of the signaling server to it.

import { WebSocketNetworkAdapter } from '@describble/ddnet';

const networkAdapter = new WebSocketNetworkAdapter('wss://ddnet-server.com');

StorageProvider

You need a StorageProvider instance for storing documents in the browser. IDBStorageProvider is an implementation using IndexedDB.

import { IDBStorageProvider } from '@describble/ddnet';

const storageProvider = new IDBStorageProvider();

DocumentSharingClient

DocumentSharingClient is the main class that you use to create and manage documents. It requires instances of SessionManager, NetworkAdapter, and StorageProvider.

import { DocumentSharingClient } from '@describble/ddnet';

const docClient = new DocumentSharingClient({
  sessionManager,
  network: networkAdapter,
  storageProvider: storageProvider,
});

Document Access Control

Once you have an instance of DocumentSharingClient, you can start creating, fetching, and updating documents.

Creating a Document

You can create a new document using the createDocument method. It will return a Document instance that you can use to perform operations on the document.

const doc = docClient.createDocument();

Finding a document by its ID

This fetches a document from the browser's local storage or in memory cache.

const doc = await docClient.findDocument('document-id');

Requesting access to a document by its ID

This fetches a document from the network and caches it in the browser's local storage. If the document is already cached, it will be returned from the cache, but the network will be queried for any updates.

const doc = await docClient.requestDocument('document-id');

List all documents

This returns a list of all document IDs that are stored in the browser's local storage.

const docs = await docClient.listDocumentIds();

Remove a document

This removes a document from the browser's local storage.

const docs = await docClient.removeDocument('document-id');

Document Operations

Now that you have a Document instance, you can perform operations on it.

Updating document content

We are using Automerge internally to manage document content. You can use the change method to update the document content.

doc.change((data) => {
  data.text = 'Hello World!';
});

Getting document content

You can get the document data using the data property.

const data = doc.data;

Updating document header

Each document has a header that contains metadata about the document.

For example, to edit who can access the document, you can do the following: All keys can be base58 encoded or Uint8Array instances.

Header is immutable, so you need to create a new header and update the document with it.

// Private key of the owner of the document
const privateKey = "G8gw9d54D3NDt4SogSBxzyBzfkyTL9Dge1EeMQgmZSAk"
const allowedClients = [
  '24YDGmC5swrdiph4pfBweYW8P8L1A4kv5K6o9BR3jHafi',
  'qBWVsxpXJHfNShbiKtgWkD6M2KNp35JaPS4Efck39t43'
];

const header = document.header.update({ allowedClients }, privateKey);
document.updateHeader(header);

Events

You can listen to events on the document using the on method.

Document change event

This event is fired when the document content changes.

doc.on('change', ({document, data}) => {
  console.log(`Document ${document.id} changed`, data);
});

Document patch event

This event is useful to know what changes were made to the document.

doc.on('patch', ({document, patches, before, after}) => {
  console.log(`Document ${document.id} patched`, patches, before, after);
});

Document header change event

This event is fired when the document header changes.

doc.on('header-updated', ({document, header}) => {
  console.log(`Document ${document.id} header changed`, header);
});

Server

DDNet requires a signaling server to establish connections between clients. The server handles the signaling process and forwards messages between clients to establish a WebRTC connection for document exchange.

import {SignalingServer, WebSocketNetwork} from '@describble/ddnet/node';

const server = new SignalingServer({
	network: new WebSocketNetwork({
		host: '0.0.0.0',
		port: 8080,
	}),
});

server.listen();

Presence

DDnet have a system called Presence that allows you to send arbitrary data to other connected clients for a specific document scope. This is useful for implementing features like cursors, chat, and other collaborative features. The data is sent to all connected clients for a specific document, and the data is not persisted.

Get presence instance

You can get an instance of Presence using the getPresence method on the DocumentSharingClient instance.

const presence = docClient.getPresence('document-id');

Send presence data

You can send presence data using the sendPresenceMessage method.

presence.sendPresenceMessage({
  type: 'cursor',
  position: {
    x: 10,
    y: 20,
  },
});

Listen to presence data

You can listen to presence data using the on method.

presence.on('update', (presenceMap) => {
    presenceMap.forEach(({
      peerId, // ID of the WebRTC connection
      client, // Client data
      presence, // Presence data
    }) => {
        console.log(`Received presence data from ${peerId}`, presence);
    });
});

We can get the current presence map using the getPresence method.

const presenceMap = presence.getPresence();

Stop listening to presence data

You can stop listening to presence data using the stop method.

presence.stop();

Usage with Vite

Vite is a modern front-end build tool that significantly improves the front-end development experience. It provides features like hot module replacement and efficient lazy loading out of the box.

If you're using DDNet with Vite, you'll need to use a specific configuration since this package uses WebAssembly (wasm).

Install Required Plugins

First, you need to install the required Vite plugins. These plugins enable support for WebAssembly and top-level await, respectively. You can install them using npm, yarn, or pnpm. Here's an example using npm:

# Using npm
$ npm install vite-plugin-wasm vite-plugin-top-level-await

# Using pnpm
$ pnpm install vite-plugin-wasm vite-plugin-top-level-await

# Using yarn
$ yarn add vite-plugin-wasm vite-plugin-top-level-await

Configuration

Create or modify your vite.config.js file and include the vite-plugin-wasm and vite-plugin-top-level-await as plugins in your configuration:

import { defineConfig } from 'vite';
import wasm from 'vite-plugin-wasm';
import topLevelAwait from 'vite-plugin-top-level-await';

export default defineConfig({
  plugins: [wasm(), topLevelAwait()],
});

This configuration ensures that Vite properly handles the WebAssembly files included in the DDNet package and supports top-level await syntax, which is commonly used with async WebAssembly functions.

With this setup, you should be able to integrate DDNet into your Vite project successfully. If you still encounter issues, please consult the respective plugin documentation or reach out for support.

Technical Overview

To understand how DDNet works, please read the technical overview.