feat(grpc): add preimage to invoice settled events (#65)

lib/grpc/GrpcService.ts

@@ -167,11 +167,12 @@ class GrpcService {
       call.write(response);
     });
 
-    this.service.on('invoice.settled', (invoice: string) => {
+    this.service.on('invoice.settled', (invoice: string, preimage: string) => {
       const response = new boltzrpc.SubscribeInvoicesResponse();
 
       response.setEvent(boltzrpc.InvoiceEvent.SETTLED);
       response.setInvoice(invoice);
+      response.setPreimage(preimage);
 
       call.write(response);
     });

lib/lightning/LndClient.ts

@@ -3,9 +3,9 @@ import grpc, { ClientReadableStream } from 'grpc';
 import Errors from './Errors';
 import Logger from '../Logger';
 import BaseClient from '../BaseClient';
-import LightningClient from './LightningClient';
 import * as lndrpc from '../proto/lndrpc_pb';
 import { ClientStatus } from '../consts/Enums';
+import LightningClient from './LightningClient';
 import { LightningClient as GrpcClient } from '../proto/lndrpc_grpc_pb';
 
 // TODO: error handling
@@ -43,8 +43,8 @@ interface LndClient {
   on(event: 'invoice.paid', listener: (invoice: string) => void): this;
   emit(event: 'invoice.paid', invoice: string): boolean;
 
-  on(event: 'invoice.settled', listener: (invoice: string) => void): this;
-  emit(event: 'invoice.settled', string: string): boolean;
+  on(event: 'invoice.settled', listener: (invoice: string, preimage: string) => void): this;
+  emit(event: 'invoice.settled', string: string, preimage: string): boolean;
 }
 
 interface LightningMethodIndex extends GrpcClient {
@@ -313,7 +313,7 @@ class LndClient extends BaseClient implements LightningClient {
           const paymentReq = invoice.getPaymentRequest();
 
           this.logger.silly(`${this.symbol} LND invoice settled: ${paymentReq}`);
-          this.emit('invoice.settled', paymentReq);
+          this.emit('invoice.settled', paymentReq, invoice.getRPreimage_asB64());
         }
       })
       .on('error', (error) => {

lib/service/Service.ts

@@ -1,14 +1,14 @@
 import { EventEmitter } from 'events';
 import { Transaction, address } from 'bitcoinjs-lib';
+import Errors from './Errors';
 import Logger from '../Logger';
-import { Info as ChainInfo } from '../chain/ChainClientInterface';
-import { Info as LndInfo } from '../lightning/LndClient';
 import SwapManager from '../swap/SwapManager';
-import WalletManager, { Currency } from '../wallet/WalletManager';
+import { OrderSide } from '../proto/boltzrpc_pb';
 import { WalletBalance } from '../wallet/Wallet';
-import Errors from './Errors';
+import { Info as LndInfo } from '../lightning/LndClient';
+import { Info as ChainInfo } from '../chain/ChainClientInterface';
+import WalletManager, { Currency } from '../wallet/WalletManager';
 import { getHexBuffer, getOutputType, getHexString } from '../Utils';
-import { OrderSide } from '../proto/boltzrpc_pb';
 
 const packageJson = require('../../package.json');
 
@@ -37,8 +37,8 @@ interface Service {
   on(even: 'invoice.paid', listener: (invoice: string) => void): this;
   emit(event: 'invoice.paid', invoice: string): boolean;
 
-  on(event: 'invoice.settled', listener: (invoice: string) => void): this;
-  emit(event: 'invoice.settled', string: string): boolean;
+  on(event: 'invoice.settled', listener: (invoice: string, preimage: string) => void): this;
+  emit(event: 'invoice.settled', string: string, preimage: string): boolean;
 }
 
 // TODO: "invalid argument" errors
@@ -208,8 +208,8 @@ class Service extends EventEmitter {
         this.emit('invoice.paid', invoice);
       });
 
-      currency.lndClient.on('invoice.settled', (invoice) => {
-        this.emit('invoice.settled', invoice);
+      currency.lndClient.on('invoice.settled', (invoice, preimage) => {
+        this.emit('invoice.settled', invoice, preimage);
       });
     });
   }

proto/boltzrpc.proto

@@ -136,6 +136,7 @@ message SubscribeInvoicesRequest {}
 message SubscribeInvoicesResponse {
   InvoiceEvent event = 1;
   string invoice = 2;
+  string preimage = 3;
 }
 
 message CreateSwapRequest {