canWriteValue

The canWriteValue method is used to decide whether a client may write a given Value.

canWriteValue(
  pathId: string,
  valueId: string,
  value: ValueOrUndefined,
  context: {[key: string]: any} | undefined,
): boolean

It is called for each Value in the changes that a writable client sends, including deletions, where the value parameter is undefined. It must be synchronous. Values for which it returns false are neither merged into the Durable Object's MergeableStore nor relayed to other clients, and a client that wrote a newer version is brought back into line with the server.

import {WsServerDurableObject} from 'tinybase/synchronizers/synchronizer-ws-server-durable-object';

export class MyDurableObject extends WsServerDurableObject {
  authorize(pathId, request) {
    return {
      context: {role: new URL(request.url).searchParams.get('role')},
    };
  }

  canWriteValue(pathId, valueId, value, {role}) {
    return role == 'staff' || valueId != 'openingHours';
  }
}