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Policy Pipelines ​

Policies can be composed into pipelines, allowing you to reject events based on multiple criteria.

This is achieved with the PipePolicy class, which accepts an array of policies and runs them in order. If any policy rejects the event, the pipeline stops and the event is rejected.

You can also use the AnyPolicy class to accept an event if any policy accepts it.

Furthermore, PipePolicy and AnyPolicy are themselves policies! So you can create nested pipelines for complex rules.

Simple Pipeline ​

The following example runs each policy in order and rejects the event if any policy rejects.

ts
import {
  AntiDuplicationPolicy,
  FiltersPolicy,
  HellthreadPolicy,
  KeywordPolicy,
  PipePolicy,
  PowPolicy,
  RegexPolicy,
} from '@nostrify/nostrify/policies';

const policy = new PipePolicy([
  new FiltersPolicy([{ kinds: [0, 1, 3, 5, 7, 1984, 9734, 9735, 10002] }]),
  new KeywordPolicy(['https://t.me/']),
  new RegexPolicy(/(🟠|🔥|😳)ChtaGPT/i),
  new PubkeyBanPolicy(['e810fafa1e89cdf80cced8e013938e87e21b699b24c8570537be92aec4b12c18']),
  new HellthreadPolicy({ limit: 100 }),
  new AntiDuplicationPolicy({ kv: await Deno.openKv(), expireIn: 60000, minLength: 50 }),
]);

const [_, eventId, ok, reason] = await policy.call(event);

TIP

Order matters. While any policy can reject an event, you can optimize performance by placing simpler policies first.

Nested Pipeline ​

You can create nested pipelines by using PipePolicy and AnyPolicy within each other.

In this example, certain phrases are banned unless the event meets a proof-of-work requirement.

ts
import { AnyPolicy, PipePolicy } from '@nostrify/nostrify/policies';

const policy = new AnyPolicy([
  new PowPolicy({ difficulty: 5 }),
  new PipePolicy([
    new KeywordPolicy(['https://t.me/']),
    new RegexPolicy(/(🟠|🔥|😳)ChtaGPT/i),
  ]),
]);

You can compose this into a bigger policy.

ts
import { AntiDuplicationPolicy, AnyPolicy, HellthreadPolicy, PipePolicy, PubkeyBanPolicy } from '@nostrify/nostrify/policies';

const policy = new PipePolicy([
  new PubkeyBanPolicy(['e810fafa1e89cdf80cced8e013938e87e21b699b24c8570537be92aec4b12c18']),
  new HellthreadPolicy({ limit: 100 }),
  new AnyPolicy([
    new PowPolicy({ difficulty: 5 }),
    new PipePolicy([
      new KeywordPolicy(['https://t.me/']),
      new RegexPolicy(/(🟠|🔥|😳)ChtaGPT/i),
    ]),
  ]),
  new AntiDuplicationPolicy({ kv: await Deno.openKv(), expireIn: 60000, minLength: 50 }),
]);
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