feat: enable meta field to be set

Ref: https://github.com/waku-org/js-waku/issues/1208

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "@waku/noise",
-  "version": "0.0.2",
+  "version": "0.0.3",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@waku/noise",
-      "version": "0.0.2",
+      "version": "0.0.3",
       "license": "Apache-2.0 OR MIT",
       "dependencies": {
         "@stablelib/chacha20poly1305": "^1.0.1",

src/codec.ts

@@ -1,5 +1,5 @@
 import { DecodedMessage } from "@waku/core/lib/message/version_0";
-import type { IDecodedMessage, IDecoder, IEncoder, IMessage, IProtoMessage } from "@waku/interfaces";
+import type { IDecodedMessage, IDecoder, IEncoder, IMessage, IMetaSetter, IProtoMessage } from "@waku/interfaces";
 import { WakuMessage } from "@waku/proto";
 import debug from "debug";
 
@@ -120,10 +120,17 @@ export class NoiseSecureMessage extends DecodedMessage implements IDecodedMessag
  */
 export class NoiseSecureTransferEncoder implements IEncoder {
   /**
-   * @param contentTopic content topic on which the encoded WakuMessages were sent
-   * @param hsResult handshake result obtained after the handshake is successful
+   * @param contentTopic content topic on which the encoded WakuMessages were sent.
+   * @param hsResult handshake result obtained after the handshake is successful.
+   * @param ephemeral whether messages should be tagged as ephemeral defaults to true.
+   * @param metaSetter callback function that set the `meta` field.
    */
-  constructor(public contentTopic: string, private hsResult: HandshakeResult, public ephemeral: boolean = true) {}
+  constructor(
+    public contentTopic: string,
+    private hsResult: HandshakeResult,
+    public ephemeral: boolean = true,
+    public metaSetter?: IMetaSetter
+  ) {}
 
   async toWire(message: IMessage): Promise<Uint8Array | undefined> {
     const protoMessage = await this.toProtoObj(message);
@@ -142,7 +149,7 @@ export class NoiseSecureTransferEncoder implements IEncoder {
 
     const payload = preparedPayload.serialize();
 
-    return {
+    const protoMessage = {
       payload,
       rateLimitProof: undefined,
       ephemeral: this.ephemeral,
@@ -151,6 +158,13 @@ export class NoiseSecureTransferEncoder implements IEncoder {
       contentTopic: this.contentTopic,
       timestamp: BigInt(timestamp.valueOf()) * OneMillion,
     };
+
+    if (this.metaSetter) {
+      const meta = this.metaSetter(protoMessage);
+      return { ...protoMessage, meta };
+    }
+
+    return protoMessage;
   }
 }
 

src/pairing.spec.ts

@@ -1,6 +1,6 @@
 import { HMACDRBG } from "@stablelib/hmac-drbg";
 import { randomBytes } from "@stablelib/random";
-import type { IDecoder, IEncoder, IMessage, ISender } from "@waku/interfaces";
+import type { IDecoder, IEncoder, IMessage, IProtoMessage, ISender } from "@waku/interfaces";
 import { expect } from "chai";
 import { EventEmitter } from "eventemitter3";
 import { pEvent } from "p-event";
@@ -13,6 +13,15 @@ import { ResponderParameters, WakuPairing } from "./pairing";
 
 const PUBSUB_TOPIC = "default";
 
+const EMPTY_PROTOMESSAGE = {
+  timestamp: undefined,
+  contentTopic: "",
+  ephemeral: undefined,
+  meta: undefined,
+  rateLimitProof: undefined,
+  version: undefined,
+};
+
 describe("js-noise: pairing object", () => {
   const rng = new HMACDRBG();
 
@@ -117,4 +126,75 @@ describe("js-noise: pairing object", () => {
       expect(message).to.be.equals("pairing has timed out");
     }
   });
+
+  it("pairs and `meta` field is encoded", async function () {
+    const bobStaticKey = generateX25519KeyPair();
+    const aliceStaticKey = generateX25519KeyPair();
+
+    // Encode the length of the payload
+    // Not a relevant real life example
+    const metaSetter = (msg: IProtoMessage & { meta: undefined }): Uint8Array => {
+      const buffer = new ArrayBuffer(4);
+      const view = new DataView(buffer);
+      view.setUint32(0, msg.payload.length, false);
+      return new Uint8Array(buffer);
+    };
+
+    const recvParameters = new ResponderParameters();
+    const bobPairingObj = new WakuPairing(sender, responder, bobStaticKey, recvParameters, undefined, { metaSetter });
+    const bobExecP1 = bobPairingObj.execute();
+
+    // Confirmation is done by manually
+    confirmAuthCodeFlow(bobPairingObj, true);
+
+    const initParameters = bobPairingObj.getPairingInfo();
+    const alicePairingObj = new WakuPairing(sender, responder, aliceStaticKey, initParameters, undefined, {
+      metaSetter,
+    });
+    const aliceExecP1 = alicePairingObj.execute();
+
+    // Confirmation is done manually
+    confirmAuthCodeFlow(alicePairingObj, true);
+
+    const [bobCodecs, aliceCodecs] = await Promise.all([bobExecP1, aliceExecP1]);
+
+    const bobEncoder = bobCodecs[0];
+    const bobDecoder = bobCodecs[1];
+    const aliceEncoder = aliceCodecs[0];
+    const aliceDecoder = aliceCodecs[1];
+
+    // We test read/write of random messages exchanged between Alice and Bob
+    // Note that we exchange more than the number of messages contained in the nametag buffer to test if they are filled correctly as the communication proceeds
+    for (let i = 0; i < 10 * MessageNametagBufferSize; i++) {
+      // Alice writes to Bob
+      let message = randomBytes(32, rng);
+      let encodedMsg = await aliceEncoder.toWire({ payload: message });
+      let readMessageProto = await bobDecoder.fromWireToProtoObj(encodedMsg!);
+      let readMessage = await bobDecoder.fromProtoObj(PUBSUB_TOPIC, readMessageProto!);
+
+      expect(uint8ArrayEquals(message, readMessage!.payload)).to.be.true;
+
+      let expectedMeta = metaSetter({
+        ...EMPTY_PROTOMESSAGE,
+        payload: readMessageProto!.payload,
+      });
+
+      expect(readMessage!.meta).to.deep.eq(expectedMeta);
+
+      // Bob writes to Alice
+      message = randomBytes(32, rng);
+      encodedMsg = await bobEncoder.toWire({ payload: message });
+      readMessageProto = await aliceDecoder.fromWireToProtoObj(encodedMsg!);
+      readMessage = await aliceDecoder.fromProtoObj(PUBSUB_TOPIC, readMessageProto!);
+
+      expect(uint8ArrayEquals(message, readMessage!.payload)).to.be.true;
+
+      expectedMeta = metaSetter({
+        ...EMPTY_PROTOMESSAGE,
+        payload: readMessageProto!.payload,
+      });
+
+      expect(readMessage!.meta).to.deep.eq(expectedMeta);
+    }
+  });
 });

src/pairing.ts

@@ -1,6 +1,6 @@
 import { HMACDRBG } from "@stablelib/hmac-drbg";
 import { randomBytes } from "@stablelib/random";
-import type { IDecoder, ISender } from "@waku/interfaces";
+import type { IDecoder, IMetaSetter, ISender } from "@waku/interfaces";
 import debug from "debug";
 import { EventEmitter } from "eventemitter3";
 import { pEvent } from "p-event";
@@ -55,6 +55,11 @@ function delay(ms: number): Promise<void> {
 
 const rng = new HMACDRBG();
 
+export interface EncoderParameters {
+  ephemeral?: boolean;
+  metaSetter?: IMetaSetter;
+}
+
 /**
  * Initiator parameters used to setup the pairing object
  */
@@ -108,13 +113,15 @@ export class WakuPairing {
    * @param myStaticKey x25519 keypair
    * @param pairingParameters Pairing parameters (depending if this is the initiator or responder)
    * @param myEphemeralKey optional ephemeral key
+   * @param encoderParameters optional parameters for the resulting encoders
    */
   constructor(
     private sender: ISender,
     private responder: Responder,
     private myStaticKey: KeyPair,
     pairingParameters: InitiatorParameters | ResponderParameters,
-    private myEphemeralKey: KeyPair = generateX25519KeyPair()
+    private myEphemeralKey: KeyPair = generateX25519KeyPair(),
+    private readonly encoderParameters: EncoderParameters = {}
   ) {
     this.randomFixLenVal = randomBytes(32, rng);
     this.myCommittedStaticKey = commitPublicKey(this.myStaticKey.publicKey, this.randomFixLenVal);
@@ -293,7 +300,7 @@ export class WakuPairing {
 
     this.eventEmitter.emit("pairingComplete");
 
-    return WakuPairing.getSecureCodec(this.contentTopic, this.handshakeResult);
+    return WakuPairing.getSecureCodec(this.contentTopic, this.handshakeResult, this.encoderParameters);
   }
 
   private async responderHandshake(): Promise<[NoiseSecureTransferEncoder, NoiseSecureTransferDecoder]> {
@@ -350,7 +357,7 @@ export class WakuPairing {
 
     this.eventEmitter.emit("pairingComplete");
 
-    return WakuPairing.getSecureCodec(this.contentTopic, this.handshakeResult);
+    return WakuPairing.getSecureCodec(this.contentTopic, this.handshakeResult, this.encoderParameters);
   }
 
   /**
@@ -358,13 +365,20 @@ export class WakuPairing {
    * to continue a session using a stored hsResult
    * @param contentTopic Content topic for the waku messages
    * @param hsResult Noise Pairing result
+   * @param encoderParameters Parameters for the resulting encoder
    * @returns an array with [NoiseSecureTransferEncoder, NoiseSecureTransferDecoder]
    */
   static getSecureCodec(
     contentTopic: string,
-    hsResult: HandshakeResult
+    hsResult: HandshakeResult,
+    encoderParameters: EncoderParameters
   ): [NoiseSecureTransferEncoder, NoiseSecureTransferDecoder] {
-    const secureEncoder = new NoiseSecureTransferEncoder(contentTopic, hsResult);
+    const secureEncoder = new NoiseSecureTransferEncoder(
+      contentTopic,
+      hsResult,
+      encoderParameters.ephemeral,
+      encoderParameters.metaSetter
+    );
     const secureDecoder = new NoiseSecureTransferDecoder(contentTopic, hsResult);
 
     return [secureEncoder, secureDecoder];