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    Class RealtimeBackplaneObjectCore

    Fans one replica's broadcast out to every other connected replica.

    This class holds no state. Not as a simplification — as a correctness requirement. Sockets are accepted with state.acceptWebSocket, the hibernation API, which lets the Workers runtime evict the Durable Object from memory while its connections stay open and re-run the constructor when the next message arrives. A membership Set held in a field would therefore empty itself on the first hibernation, and every test that never hibernates would still pass. state.getWebSockets() survives hibernation and is the only source of truth used here.

    The payload is re-broadcast verbatim, never parsed. That costs no CPU per fan-out, makes it impossible for this object to corrupt a frame, and — since a Durable Object class is deployed by the application rather than by this package — means a future widening of RealtimeFrame needs no redeploy of the object to carry the new field.

    The application owns the class; this owns the behavior:

    import { DurableObject } from 'cloudflare:workers';
    import { RealtimeBackplaneObjectCore } from '@setu-ts/cloudflare-plugin';

    export class RealtimeBackplaneObject extends DurableObject {
      #core = new RealtimeBackplaneObjectCore(this.ctx);

      override fetch(request: Request): Promise<Response> {
        return this.#core.fetch(request);
      }
      webSocketMessage(ws: WebSocket, message: string | ArrayBuffer): void {
        this.#core.webSocketMessage(ws, message);
      }
      webSocketClose(ws: WebSocket, code: number, reason: string, wasClean: boolean): void {
        this.#core.webSocketClose(ws, code, reason, wasClean);
      }
    }

    0.2.0

    Index
    constructor
    fetch webSocketClose webSocketError webSocketMessage

    • Handles a replica disconnecting.

      Nothing is tracked, so nothing needs removing — the runtime drops the socket from getWebSockets() on its own. The handler exists so the application's class can forward it without a branch, and so the close is acknowledged rather than left to the runtime's default.

      Parameters

      • socket: IDurableObjectWebSocket

        The socket that closed

      • code: number

        The close code the peer sent

      • reason: string

        The close reason the peer sent

      Returns void

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