PartyKitServer (Legacy Server API)

You may encounter PartyKit code that exports a plain object conforming to the PartyKitServer type, instead of exporting a class that implements the PartyServer interface.

import { PartyKitRoom, PartyKitServer } from "partykit/server";

export default {
  async onConnect(connection, room: PartyKitRoom) {},
  async onRequest(request: Request, room: PartyKitRoom) {}
} satisfies PartyKitServer;

API

import { PartyKitContext, PartyKitRoom, PartyKitServer } from "partykit/server";

export default {
  async onConnect(connection, room: PartyKitRoom, ctx: PartyKitContext) {
    // `connection` is a WebSocket object, but with a few extra properties
    // and methods. See the PartyKitConnection type for more details.
    connection.send("Hello, world!"); // Send a message to the client
    connection.addEventListener("message", (event) => {
      console.log(event.data); // Log a message from the client
    });
  },
  async onRequest(request: Request, room: PartyKitRoom) {
    // ...
  }
} satisfies PartyKitServer;

onConnect

This function onConnect will be called whenever a new client (usually a browser, but it can be any device that can make WebSocket connections) connects to your project. The connection argument is a WebSocket object that you can use to send and receive messages to/from the client (with a couple of additional properties).

onRequest

The function onRequest will be called whenever a client makes an HTTP request to your project. The request argument is a Request object that you can use to get information about the request, and the room argument is the same as the one in onConnect.

request: Request

A Request object that contains information about the HTTP request that initiated the WebSocket connection. This is useful if you want to get information about the client that’s connecting to your project. For example, you can get the IP address of the client like this: ctx.request.headers.get('cf-connecting-ip')

room: PartyKitRoom

The room argument passed on onRequest and onConnect is an object that contains information about the room that the client is in. It has the following properties:

id: string

A string that uniquely identifies the room. This is usually associated with a single document, drawing, game session, or other collaborative experience. For example, if you’re building a collaborative drawing app, this would be the id of the drawing that the client is currently viewing.

connections: Map<string, {id: string, socket: PartyKitConnection}>

A Map of connection IDs to all the connections in the room. The ID is usually associated with a single client. For example, if you’re building a collaborative drawing app, this would be the id of the user that’s currently viewing the drawing. You can either specify this id yourself by passing a _pk query param in the WebSocket connection, or let PartyKit generate one for you.

env: Record<string, any>

A map of all the environment variables that you’ve set for your project. See the vars section for more details.

storage: (TODO, see Durable Objects storage API as a reference)

internalID: string

This too is a string that uniquely identifies the room, but it’s not meant to be directly used by your application. It’s used internally by the PartyKit platform to identify the room.