Swap!

README.md

@@ -26,6 +26,10 @@ run `go install` to get dependencies installed
 ### For local testing: ###
 run `go test`
 
+### To run an individual test in verbose mode ###
+`go test -run [TestName] [TestDirectory] -v -count 1`
+i.e. `go test -run TestGetSwapPayload ./pkg/service -v -count 1`
+
 ### Unit21: ### 
 This is a 3rd party service that offers the ability to evaluate risk at a transaction level and identify fraud. A client file exists to connect to their API. Documentation is here: https://docs.unit21.ai/reference/entities-api
 You can create a test API key on the Unit21 dashboard. You will need to be setup as an Admin. Here are the instructions: https://docs.unit21.ai/reference/generate-api-keys

api/handler/quotes.go

@@ -11,6 +11,7 @@ import (
 
 type Quotes interface {
 	Quote(c echo.Context) error
+	OffRampQuote(c echo.Context) error
 	RegisterRoutes(g *echo.Group, ms ...echo.MiddlewareFunc)
 }
 
@@ -47,11 +48,28 @@ func (q quote) Quote(c echo.Context) error {
 	return c.JSON(http.StatusOK, res)
 }
 
+func (q quote) OffRampQuote(c echo.Context) error {
+	var body model.OffRampRequest
+	err := c.Bind(&body)
+	if err != nil {
+		LogStringError(c, err, "quote: offrampquote bind")
+		return BadRequestError(c)
+	}
+	SanitizeChecksums(&body.FromToken, &body.UserAddress)
+	res, err := q.Service.OffRampQuote(body)
+	if err != nil {
+		LogStringError(c, err, "quote: offrampquote")
+		return c.JSON(http.StatusInternalServerError, JSONError{Message: "Quote Service Failed"})
+	}
+	return c.JSON(http.StatusOK, res)
+}
+
 func (q quote) RegisterRoutes(g *echo.Group, ms ...echo.MiddlewareFunc) {
 	if g == nil {
 		panic("No group attached to the Quote Handler")
 	}
 	q.Group = g
 	g.Use(ms...)
 	g.POST("", q.Quote)
+	g.POST("/offramp", q.OffRampQuote)
 }

pkg/model/swap.go

@@ -0,0 +1,32 @@
+package model
+
+type OffRampRequest struct {
+	UserAddress string `json:"userAddress"`
+	ChainID     int    `json:"chainID"`
+	FromToken   string `json:"fromToken"`
+	Amount      string `json:"amount"`
+}
+
+type OffRampExecutionRequest struct {
+	OffRampRequest
+	Quote
+	Signature string `json:"signature"`
+	CardToken string `json:"cardToken"`
+}
+
+type SwapRequest struct {
+	UserAddress string `json:"userAddress"`
+	ChainID     int    `json:"chainID"`
+	FromToken   string `json:"fromToken"`
+	ToToken     string `json:"toToken"`
+	Amount      string `json:"amount"`
+}
+
+type SwapCrossChainRequest struct {
+	UserAddress string `json:"userAddress"`
+	FromChain   int    `json:"fromChain"`
+	ToChain     int    `json:"toChain"`
+	FromToken   string `json:"fromToken"`
+	ToToken     string `json:"toToken"`
+	Amount      string `json:"amount"`
+}

pkg/service/cost.go

@@ -43,6 +43,7 @@ type CostCache struct {
 type Cost interface {
 	EstimateTransaction(p EstimationParams, chain Chain) (model.Quote, error)
 	LookupUSD(coin string, quantity float64) (float64, error)
+	CoingeckoUSD(coin string, quantity float64) (float64, error)
 }
 
 type cost struct {
@@ -135,7 +136,7 @@ func (c cost) LookupUSD(coin string, quantity float64) (float64, error) {
 	}
 	if cacheObject == (CostCache{}) || (err == nil && time.Now().Unix()-cacheObject.Timestamp > c.getExternalAPICallInterval(10, 6)) {
 		cacheObject.Timestamp = time.Now().Unix()
-		cacheObject.Value, err = c.coingeckoUSD(coin, 1)
+		cacheObject.Value, err = c.CoingeckoUSD(coin, 1)
 		if err != nil {
 			return 0, common.StringError(err)
 		}
@@ -169,7 +170,7 @@ func (c cost) lookupGas(network string) (float64, error) {
 	return cacheObject.Value, nil
 }
 
-func (c cost) coingeckoUSD(coin string, quantity float64) (float64, error) {
+func (c cost) CoingeckoUSD(coin string, quantity float64) (float64, error) {
 	requestURL := os.Getenv("COINGECKO_API_URL") + "simple/price?ids=" + coin + "&vs_currencies=usd"
 	var res map[string]interface{}
 	err := common.GetJsonGeneric(requestURL, &res)

pkg/service/executor.go

@@ -27,6 +27,15 @@ type ContractCall struct {
 	TxGasLimit string   // Gwei gas limit ie "210000 gwei"
 }
 
+type EncodedContractCall struct {
+	Data     string // Hex encoded function, parameters etc
+	From     string // Address
+	Gas      string
+	GasPrice big.Int
+	To       string // Address
+	Value    string
+}
+
 type CallEstimate struct {
 	Value   big.Int
 	Gas     uint64
@@ -36,6 +45,7 @@ type CallEstimate struct {
 type Executor interface {
 	Initialize(RPC string) error
 	Initiate(call ContractCall) (string, *big.Int, error)
+	InitiateEncoded(call EncodedContractCall) (string, *big.Int, error)
 	Estimate(call ContractCall) (CallEstimate, error)
 	TxWait(txID string) (uint64, error)
 	Close() error
@@ -145,6 +155,81 @@ func (e executor) Estimate(call ContractCall) (CallEstimate, error) {
 	return CallEstimate{Value: *value, Gas: estimatedGas, Success: true}, nil
 }
 
+func (e executor) InitiateEncoded(call EncodedContractCall) (string, *big.Int, error) {
+	// Get private key
+	skStr, err := stringCommon.DecryptBlobFromKMS(os.Getenv("EVM_PRIVATE_KEY"))
+	if err != nil {
+		return "", nil, stringCommon.StringError(err)
+	}
+	sk, err := crypto.ToECDSA(common.FromHex(skStr))
+	if err != nil {
+		return "", nil, stringCommon.StringError(err)
+	}
+	// TODO: avoid panicking so that we get an intelligible error message
+	to := w3.A(call.To)
+	value := w3.I(call.Value)
+	// Get public key
+	publicKeyECDSA, ok := sk.Public().(*ecdsa.PublicKey)
+	if !ok {
+		return "", nil, stringCommon.StringError(errors.New("Estimate: Error casting public key to ECDSA"))
+	}
+	sender := crypto.PubkeyToAddress(*publicKeyECDSA)
+
+	// Use provided gas limit
+	gasLimit := w3.I(call.Gas)
+
+	// Get chainID from state
+	var chainId64 uint64
+	err = e.client.Call(eth.ChainID().Returns(&chainId64))
+	if err != nil {
+		return "", nil, stringCommon.StringError(err)
+	}
+
+	// Get sender nonce
+	var nonce uint64
+	err = e.client.Call(eth.Nonce(sender, nil).Returns(&nonce))
+	if err != nil {
+		return "", nil, stringCommon.StringError(err)
+	}
+
+	// // Get dynamic fee tx gas params
+	tipCap, _ := e.geth.SuggestGasTipCap(context.Background())
+	feeCap, _ := e.geth.SuggestGasPrice(context.Background())
+
+	// // Function is already encoded along with parameters
+	// data := []byte(call.Data)
+	data := w3.B(call.Data)
+
+	// Type conversion for chainID
+	chainIdBig := new(big.Int).SetUint64(chainId64)
+
+	// Get signer type, this is used to encode the tx
+	signer := types.LatestSignerForChainID(chainIdBig)
+
+	// Generate blockchain tx
+	dynamicFeeTx := types.DynamicFeeTx{
+		ChainID:   chainIdBig,
+		Nonce:     nonce,
+		GasTipCap: tipCap,
+		GasFeeCap: feeCap,
+		Gas:       gasLimit.Uint64(),
+		To:        &to,
+		Value:     value,
+		Data:      data,
+	}
+	// Sign it
+	tx := types.MustSignNewTx(sk, signer, &dynamicFeeTx)
+
+	// Call tx and retrieve hash
+	var hash common.Hash
+	err = e.client.Call(eth.SendTx(tx).Returns(&hash))
+	if err != nil {
+		// Execution failed!
+		return "", nil, stringCommon.StringError(err)
+	}
+	return hash.String(), value, nil
+}
+
 func (e executor) Initiate(call ContractCall) (string, *big.Int, error) {
 	// Get private key
 	skStr, err := stringCommon.DecryptBlobFromKMS(os.Getenv("EVM_PRIVATE_KEY"))