WebSocket Provider for Yjs
The Websocket Provider implements a classical client server model. Clients connect to a single endpoint over Websocket. The server distributes awareness information and document updates among clients.
This repository contains a simple in-memory backend that can persist to databases, but it can't be scaled easily. The y-redis repository contains an alternative backend that is scalable, provides auth*, and can persist to different backends.
The Websocket Provider is a solid choice if you want a central source that handles authentication and authorization. Websockets also send header information and cookies, so you can use existing authentication mechanisms with this server.
- Supports cross-tab communication. When you open the same document in the same browser, changes on the document are exchanged via cross-tab communication (Broadcast Channel and localStorage as fallback).
- Supports exchange of awareness information (e.g. cursors).
npm i y-websocket
This repository implements a basic server that you can adopt to your specific use-case. (source code)
Start a y-websocket server:
HOST=localhost PORT=1234 npx y-websocket
import * as Y from 'yjs'
import { WebsocketProvider } from 'y-websocket'
const doc = new Y.Doc()
const wsProvider = new WebsocketProvider('ws:https://localhost:1234', 'my-roomname', doc)
wsProvider.on('status', event => {
console.log(event.status) // logs "connected" or "disconnected"
})
The WebSocket provider requires a WebSocket
object to create connection to a server. You can polyfill WebSocket support in Node.js using the ws
package.
const wsProvider = new WebsocketProvider('ws:https://localhost:1234', 'my-roomname', doc, { WebSocketPolyfill: require('ws') })
import { WebsocketProvider } from 'y-websocket'
- Create a new websocket-provider instance. As long as this provider, or the connected ydoc, is not destroyed, the changes will be synced to other clients via the connected server. Optionally, you may specify a configuration object. The following default values of wsOpts can be overwritten.
wsProvider = new WebsocketProvider(serverUrl: string, room: string, ydoc: Y.Doc [, wsOpts: WsOpts])
wsOpts = {
// Set this to `false` if you want to connect manually using wsProvider.connect()
connect: true,
// Specify a query-string / url parameters that will be url-encoded and attached to the `serverUrl`
// I.e. params = { auth: "bearer" } will be transformed to "?auth=bearer"
params: {}, // Object<string,string>
// You may polyill the Websocket object (https://developer.mozilla.org/en-US/docs/Web/API/WebSocket).
// E.g. In nodejs, you could specify WebsocketPolyfill = require('ws')
WebsocketPolyfill: Websocket,
// Specify an existing Awareness instance - see https://github.com/yjs/y-protocols
awareness: new awarenessProtocol.Awareness(ydoc),
// Specify the maximum amount to wait between reconnects (we use exponential backoff).
maxBackoffTime: 2500
}
- True if this instance is currently connected to the server.
- True if this instance is currently connecting to the server.
- If false, the client will not try to reconnect.
- True if this instance is currently communicating to other browser-windows via BroadcastChannel.
- True if this instance is currently connected and synced with the server.
- The specified url parameters. This can be safely updated, the new values will be used when a new connction is established. If this contains an auth token, it should be updated regularly.
- Disconnect from the server and don't try to reconnect.
- Establish a websocket connection to the websocket-server. Call this if you recently disconnected or if you set wsOpts.connect = false.
- Destroy this wsProvider instance. Disconnects from the server and removes all event handlers.
- Add an event listener for the sync event that is fired when the client received content from the server.
- Receive updates about the current connection status.
- Fires when the underlying websocket connection is closed. It forwards the websocket event to this event handler.
- Fires when the underlying websocket connection closes with an error. It forwards the websocket event to this event handler.
wsProvider.wsconnected: boolean
wsProvider.wsconnecting: boolean
wsProvider.shouldConnect: boolean
wsProvider.bcconnected: boolean
wsProvider.synced: boolean
wsProvider.params : boolean
wsProvider.disconnect()
wsProvider.connect()
wsProvider.destroy()
wsProvider.on('sync', function(isSynced: boolean))
wsProvider.on('status', function({ status: 'disconnected' | 'connecting' | 'connected' }))
wsProvider.on('connection-close', function(WSClosedEvent))
wsProvider.on('connection-error', function(WSErrorEvent))
Start a y-websocket server:
HOST=localhost PORT=1234 npx y-websocket
Since npm symlinks the y-websocket
executable from your local ./node_modules/.bin
folder, you can simply run npx. The PORT
environment variable already defaults to 1234, and HOST
defaults to localhost
.
Persist document updates in a LevelDB database.
See LevelDB Persistence for more info.
HOST=localhost PORT=1234 YPERSISTENCE=./dbDir node ./node_modules/y-websocket/bin/server.js
Send a debounced callback to an HTTP server (POST
) on document update. Note that this implementation doesn't implement a retry logic in case the CALLBACK_URL
does not work.
Can take the following ENV variables:
CALLBACK_URL
: Callback server URLCALLBACK_DEBOUNCE_WAIT
: Debounce time between callbacks (in ms). Defaults to 2000 msCALLBACK_DEBOUNCE_MAXWAIT
: Maximum time to wait before callback. Defaults to 10 secondsCALLBACK_TIMEOUT
: Timeout for the HTTP call. Defaults to 5 secondsCALLBACK_OBJECTS
: JSON of shared objects to get data ('{"SHARED_OBJECT_NAME":"SHARED_OBJECT_TYPE}'
)
CALLBACK_URL=https://localhost:3000/ CALLBACK_OBJECTS='{"prosemirror":"XmlFragment"}' npm start
This sends a debounced callback to localhost:3000
2 seconds after receiving an update (default DEBOUNCE_WAIT
) with the data of an XmlFragment named "prosemirror"
in the body.
The MIT License © Kevin Jahns