keysend: low-level work and instructions

controllers/keysend.go

@@ -0,0 +1,49 @@
+package controllers
+
+import (
+	"fmt"
+
+	"github.com/getAlby/lndhub.go/lib"
+	"github.com/getAlby/lndhub.go/lib/service"
+	"github.com/labstack/echo/v4"
+)
+
+// KeySendController : Pay invoice controller struct
+type KeySendController struct {
+	svc *service.LndhubService
+}
+
+func NewKeySendController(svc *service.LndhubService) *KeySendController {
+	return &KeySendController{svc: svc}
+}
+
+type KeySendRequestBody struct {
+	Amount      int64  `json:"amount" validate:"required"`
+	Destination string `json:"destination" validate:"required"`
+	Memo        string `json:"memo" validate:"omitempty"`
+}
+
+type KeySendResponseBody struct {
+	RHash              *lib.JavaScriptBuffer `json:"payment_hash,omitempty"`
+	Amount             int64                 `json:"num_satoshis,omitempty"`
+	Description        string                `json:"description,omitempty"`
+	Destination        string                `json:"destination,omitempty"`
+	DescriptionHashStr string                `json:"description_hash,omitempty"`
+	PaymentError       string                `json:"payment_error,omitempty"`
+	PaymentPreimage    *lib.JavaScriptBuffer `json:"payment_preimage,omitempty"`
+	PaymentRoute       *service.Route        `json:"route,omitempty"`
+}
+
+// KeySend : Pay invoice Controller
+func (controller *KeySendController) KeySend(c echo.Context) error {
+	/*
+		TODO: copy code from payinvoice.ctrl.go and modify where needed:
+		- do not decode the payment request because there is no payment request.
+		  Instead, construct the lnrpc.PaymentRequest manually from the KeySendRequestBody.
+		- add outgoing invoice: same as payinvoice, make sure to set keysend=true
+		- do a balance check: same as payinvoice, in fact do this before doing anything else
+		- call svc.PayInvoice : same as payinvoice as long as keysend=true in Invoice
+		- response will be slightly different due to lack of payment request
+	*/
+	return fmt.Errorf("TODO")
+}

db/migrations/20220304103000_keysend_invoice.up.sql

@@ -0,0 +1 @@
+alter table invoices add column keysend boolean;

db/models/invoice.go

@@ -21,6 +21,7 @@ type Invoice struct {
 	RHash                string       `json:"r_hash"`
 	Preimage             string       `json:"preimage" bun:",nullzero"`
 	Internal             bool         `json:"internal" bun:",nullzero"`
+	KeySend              bool         `json:"keysend" bun:",nullzero"`
 	State                string       `json:"state" bun:",default:'initialized'"`
 	ErrorMessage         string       `json:"error_message" bun:",nullzero"`
 	AddIndex             uint64       `json:"add_index" bun:",nullzero"`

integration_tests/keysend_test.go

@@ -0,0 +1,12 @@
+package integration_tests
+
+func (suite *PaymentTestSuite) TestKeysendPayment() {
+	// destination pubkey strings:
+	// simnet-lnd-2: 025c1d5d1b4c983cc6350fc2d756fbb59b4dc365e45e87f8e3afe07e24013e8220
+	// simnet-lnd-3: 03c7092d076f799ab18806743634b4c9bb34e351bdebc91d5b35963f3dc63ec5aa
+	// simnet-cln-1: 0242898f86064c2fd72de22059c947a83ba23e9d97aedeae7b6dba647123f1d71b
+	// (put this in utils)
+	// fund account, test making keysend payments to any of these nodes (lnd-2 and lnd-3 is fine)
+	// test making a keysend payment to a destination that does not exist
+	// test making a keysend payment with a memo that is waaaaaaay too long
+}

lib/service/invoices.go

@@ -98,6 +98,9 @@ func (svc *LndhubService) SendInternalPayment(ctx context.Context, invoice *mode
 }
 
 func (svc *LndhubService) SendPaymentSync(ctx context.Context, invoice *models.Invoice) (SendPaymentResponse, error) {
+	if invoice.KeySend {
+		return svc.KeySendPaymentSync(ctx, invoice)
+	}
 	sendPaymentResponse := SendPaymentResponse{}
 	// TODO: set dynamic fee limit
 	feeLimit := lnrpc.FeeLimit{

lib/service/ln.go

@@ -2,10 +2,60 @@ package service
 
 import (
 	"context"
+	"encoding/hex"
+	"errors"
 
+	"github.com/getAlby/lndhub.go/db/models"
 	"github.com/lightningnetwork/lnd/lnrpc"
 )
 
+//https://github.com/hsjoberg/blixt-wallet/blob/9fcc56a7dc25237bc14b85e6490adb9e044c009c/src/utils/constants.ts#L5
+const (
+	KEYSEND_CUSTOM_RECORD = 5482373484
+	TLV_WHATSAT_MESSAGE   = 34349334
+	TLV_RECORD_NAME       = 128100
+)
+
 func (svc *LndhubService) GetInfo(ctx context.Context) (*lnrpc.GetInfoResponse, error) {
 	return svc.LndClient.GetInfo(ctx, &lnrpc.GetInfoRequest{})
 }
+
+func (svc *LndhubService) KeySendPaymentSync(ctx context.Context, invoice *models.Invoice) (result SendPaymentResponse, err error) {
+	sendPaymentResponse := SendPaymentResponse{}
+	// TODO: set dynamic fee limit
+	feeLimit := lnrpc.FeeLimit{
+		Limit: &lnrpc.FeeLimit_Fixed{
+			Fixed: 300,
+		},
+	}
+	preImage := makePreimageHex()
+	// Prepare the LNRPC call
+	//See: https://github.com/hsjoberg/blixt-wallet/blob/9fcc56a7dc25237bc14b85e6490adb9e044c009c/src/lndmobile/index.ts#L251-L270
+	sendPaymentRequest := lnrpc.SendRequest{
+		Dest:              []byte(invoice.DestinationPubkeyHex),
+		Amt:               invoice.Amount,
+		FeeLimit:          &feeLimit,
+		DestFeatures:      []lnrpc.FeatureBit{lnrpc.FeatureBit_TLV_ONION_REQ},
+		DestCustomRecords: map[uint64][]byte{KEYSEND_CUSTOM_RECORD: preImage, TLV_WHATSAT_MESSAGE: []byte(invoice.Memo)},
+	}
+
+	// Execute the payment
+	sendPaymentResult, err := svc.LndClient.SendPaymentSync(ctx, &sendPaymentRequest)
+	if err != nil {
+		return sendPaymentResponse, err
+	}
+
+	// If there was a payment error we return an error
+	if sendPaymentResult.GetPaymentError() != "" || sendPaymentResult.GetPaymentPreimage() == nil {
+		return sendPaymentResponse, errors.New(sendPaymentResult.GetPaymentError())
+	}
+
+	preimage := sendPaymentResult.GetPaymentPreimage()
+	sendPaymentResponse.PaymentPreimage = preimage
+	sendPaymentResponse.PaymentPreimageStr = hex.EncodeToString(preimage[:])
+	paymentHash := sendPaymentResult.GetPaymentHash()
+	sendPaymentResponse.PaymentHash = paymentHash
+	sendPaymentResponse.PaymentHashStr = hex.EncodeToString(paymentHash[:])
+	sendPaymentResponse.PaymentRoute = &Route{TotalAmt: sendPaymentResult.PaymentRoute.TotalAmt, TotalFees: sendPaymentResult.PaymentRoute.TotalFees}
+	return sendPaymentResponse, nil
+}