feat: use forwarded payments

package.json

@@ -36,7 +36,7 @@
     "eventemitter2": "^2.2.1",
     "five-bells-shared": "^25.1.0",
     "ilp": "~11.2.0",
-    "ilp-packet": "~1.3.0",
+    "ilp-packet": "~1.6.0",
     "ilp-plugin-bells": "^15.0.0",
     "ilp-routing": "~10.1.0",
     "lodash": "^4.6.1",

src/lib/route-builder.js

@@ -154,14 +154,14 @@ class RouteBuilder {
     }
     let ilpPacket
     try {
-      ilpPacket = packet.deserializeIlpPayment(Buffer.from(sourceTransfer.ilp, 'base64'))
+      ilpPacket = packet.deserializeIlpPacket(Buffer.from(sourceTransfer.ilp, 'base64'))
     } catch (err) {
       log.debug('error parsing ILP packet: ' + sourceTransfer.ilp)
       throw new IncomingTransferError(ilpErrors.F01_Invalid_Packet({
         message: 'source transfer has invalid ILP packet'
       }))
     }
-    const destinationAddress = ilpPacket.account
+    const destinationAddress = ilpPacket.data.account
     const myAddress = this.ledgers.getPlugin(sourceTransfer.ledger).getAccount()
     if (startsWith(destinationAddress, myAddress)) {
       log.debug(
@@ -173,19 +173,20 @@ class RouteBuilder {
     }
 
     log.debug('constructing transfer for ILP packet with account=%s amount=%s',
-      ilpPacket.account, ilpPacket.amount)
+      ilpPacket.data.account, ilpPacket.data.amount)
 
     const sourceLedger = sourceTransfer.ledger
 
-    // If the ILP amount field is zero, it means we should forward the maximum
-    // we are willing to.
-    const nextHop = (ilpPacket.amount === '0')
-      ? await this.quoter.findBestPathForSourceAmount(sourceLedger, ilpPacket.account, sourceTransfer.amount)
-      : await this.quoter.findBestPathForFinalAmount(sourceLedger, ilpPacket.account, ilpPacket.amount)
+    // If the ILP packet is of type Forwarded Payment, it means we should forward the maximum
+    // we are willing to. Note that this feature is experimental, and support for it may disappear
+    // or change at any time.
+    const nextHop = (ilpPacket.type === packet.Type.TYPE_ILP_FORWARDED_PAYMENT)
+      ? await this.quoter.findBestPathForSourceAmount(sourceLedger, ilpPacket.data.account, sourceTransfer.amount)
+      : await this.quoter.findBestPathForFinalAmount(sourceLedger, ilpPacket.data.account, ilpPacket.data.amount)
     if (!nextHop) {
       log.info('could not find quote for source transfer: ' + JSON.stringify(sourceTransfer))
       throw new IncomingTransferError(ilpErrors.F02_Unreachable({
-        message: 'No route found from: ' + sourceLedger + ' to: ' + ilpPacket.account
+        message: 'No route found from: ' + sourceLedger + ' to: ' + ilpPacket.data.account
       }))
     }
     this._verifyLedgerIsConnected(nextHop.destinationLedger)

test/paymentsSpec.js

@@ -280,7 +280,7 @@ describe('Payments', function () {
     })
   })
 
-  it('uses best rate when ilp packet amount = 0', async function () {
+  it('uses best rate when ilp packet is a forwarded payment', async function () {
     const sendSpy = sinon.spy(this.mockPlugin2, 'sendTransfer')
     await this.mockPlugin1.emitAsync('incoming_prepare', {
       id: '5857d460-2a46-4545-8311-1539d99e78e8',
@@ -289,9 +289,8 @@ describe('Payments', function () {
       amount: '100',
       executionCondition: 'ni:///sha-256;I3TZF5S3n0-07JWH0s8ArsxPmVP6s-0d0SqxR6C3Ifk?fpt=preimage-sha-256&cost=6',
       expiresAt: (new Date(START_DATE + 1000)).toISOString(),
-      ilp: packet.serializeIlpPayment({
-        account: 'mock.test2.bob',
-        amount: '0'
+      ilp: packet.serializeIlpForwardedPayment({
+        account: 'mock.test2.bob'
       }).toString('base64')
     })
 

test/routeBuilderSpec.js

@@ -168,10 +168,9 @@ describe('RouteBuilder', function () {
       assert.deepEqual(destinationTransfer.ilp, ilpPacket)
     })
 
-    it('uses best rate when ilp packet amount = 0', async function () {
-      const ilpPacket = packet.serializeIlpPayment({
-        account: bobB,
-        amount: '0'
+    it('uses best rate when ilp packet is a forwarded payment', async function () {
+      const ilpPacket = packet.serializeIlpForwardedPayment({
+        account: bobB
       }).toString('base64')
       const destinationTransfer = await this.builder.getDestinationTransfer({
         id: 'fd7ecefd-8eb8-4e16-b7c8-b67d9d6995f5',