From eb6369806e5b9bf2b5e80f7dde0516478b40c4b9 Mon Sep 17 00:00:00 2001
From: achingbrain <alex@achingbrain.net>
Date: Tue, 12 Mar 2024 10:34:32 +0100
Subject: [PATCH] feat: expose .dns property on @helia/interface

Exposes a `.dns` property on the Helia interface for use with other
modules such as @helia/ipns.

Refs: https://github.com/ipfs/helia-verified-fetch/pull/13#issuecomment-1983944596
---
 packages/interface/package.json |  1 +
 packages/interface/src/index.ts |  7 +++++++
 packages/utils/src/index.ts     | 11 +++++++++++
 3 files changed, 19 insertions(+)

diff --git a/packages/interface/package.json b/packages/interface/package.json
index 6a3fee995..b54609812 100644
--- a/packages/interface/package.json
+++ b/packages/interface/package.json
@@ -71,6 +71,7 @@
   },
   "dependencies": {
     "@libp2p/interface": "^1.1.4",
+    "@multiformats/dns": "^1.0.1",
     "interface-blockstore": "^5.2.10",
     "interface-datastore": "^8.2.11",
     "interface-store": "^5.1.8",
diff --git a/packages/interface/src/index.ts b/packages/interface/src/index.ts
index a12024ccb..303dcea1a 100644
--- a/packages/interface/src/index.ts
+++ b/packages/interface/src/index.ts
@@ -18,6 +18,7 @@ import type { Blocks } from './blocks.js'
 import type { Pins } from './pins.js'
 import type { Routing } from './routing.js'
 import type { AbortOptions, ComponentLogger } from '@libp2p/interface'
+import type { DNS } from '@multiformats/dns'
 import type { Datastore } from 'interface-datastore'
 import type { MultihashHasher } from 'multiformats'
 import type { CID } from 'multiformats/cid'
@@ -67,6 +68,12 @@ export interface Helia {
    */
   hashers: Record<number, MultihashHasher>
 
+  /**
+   * The DNS property can be used to perform lookups of various record types and
+   * will use a resolver appropriate to the current platform.
+   */
+  dns: DNS
+
   /**
    * Starts the Helia node
    */
diff --git a/packages/utils/src/index.ts b/packages/utils/src/index.ts
index 7890f8795..f0d84cd08 100644
--- a/packages/utils/src/index.ts
+++ b/packages/utils/src/index.ts
@@ -19,6 +19,7 @@
 
 import { contentRoutingSymbol, peerRoutingSymbol, start, stop } from '@libp2p/interface'
 import { defaultLogger } from '@libp2p/logger'
+import { dns } from '@multiformats/dns'
 import drain from 'it-drain'
 import { CustomProgressEvent } from 'progress-events'
 import { PinsImpl } from './pins.js'
@@ -32,6 +33,7 @@ import type { DAGWalker, GCOptions, Helia as HeliaInterface, Routing } from '@he
 import type { BlockBroker } from '@helia/interface/blocks'
 import type { Pins } from '@helia/interface/pins'
 import type { ComponentLogger, Logger } from '@libp2p/interface'
+import type { DNS } from '@multiformats/dns'
 import type { Blockstore } from 'interface-blockstore'
 import type { Datastore } from 'interface-datastore'
 import type { CID } from 'multiformats/cid'
@@ -103,6 +105,11 @@ export interface HeliaInit {
    * Components used by subclasses
    */
   components?: Record<string, any>
+
+  /**
+   * An optional DNS implementation used the perform queries.
+   */
+  dns?: DNS
 }
 
 interface Components {
@@ -112,6 +119,7 @@ interface Components {
   dagWalkers: Record<number, DAGWalker>
   logger: ComponentLogger
   blockBrokers: BlockBroker[]
+  dns: DNS
 }
 
 export class Helia implements HeliaInterface {
@@ -122,6 +130,7 @@ export class Helia implements HeliaInterface {
   public routing: Routing
   public dagWalkers: Record<number, DAGWalker>
   public hashers: Record<number, MultihashHasher>
+  public dns: DNS
   private readonly log: Logger
 
   constructor (init: HeliaInit) {
@@ -129,6 +138,7 @@ export class Helia implements HeliaInterface {
     this.log = this.logger.forComponent('helia')
     this.hashers = defaultHashers(init.hashers)
     this.dagWalkers = defaultDagWalkers(init.dagWalkers)
+    this.dns = init.dns ?? dns()
 
     const components: Components = {
       blockstore: init.blockstore,
@@ -137,6 +147,7 @@ export class Helia implements HeliaInterface {
       dagWalkers: this.dagWalkers,
       logger: this.logger,
       blockBrokers: [],
+      dns: this.dns,
       ...(init.components ?? {})
     }