Tomar precios directamente de OpenSea

No sabía que existía total_price

etherscan.go

@@ -1,50 +0,0 @@
-package main
-
-import (
-	"encoding/json"
-	"errors"
-	"math"
-	"net/http"
-	"os"
-	"strconv"
-)
-
-type Transaction struct {
-	Value float64
-}
-
-func GetTransaction(id string) (Transaction, error) {
-	transaction := Transaction{}
-	key, exists := os.LookupEnv("ETHERSCAN_KEY")
-	if !exists {
-		return transaction, errors.New("No tengo ETHERSCAN_KEY, conseguir en https://etherscan.io/apis")
-	}
-	res, err := http.DefaultClient.Get("https://api.etherscan.io/api?module=proxy" +
-		"&action=eth_getTransactionByHash" +
-		"&txhash=" + id +
-		"&apikey=" + key)
-	if err != nil {
-		return transaction, err
-	}
-	result := struct {
-		Result struct {
-			Value string `json:"value"`
-		} `json:"result,omitempty"`
-		Error struct {
-			Message string `json:"message"`
-		} `json:"error,omitempty"`
-	}{}
-	err = json.NewDecoder(res.Body).Decode(&result)
-	if err != nil {
-		return transaction, err
-	}
-	if len(result.Error.Message) > 0 {
-		return transaction, errors.New(result.Error.Message)
-	}
-	parsed, err := strconv.ParseUint(result.Result.Value[2:], 16, 64)
-	if err != nil {
-		return transaction, err
-	}
-	transaction.Value = float64(parsed) / math.Pow10(18)
-	return transaction, nil
-}

main.go

@@ -102,18 +102,17 @@ func getRandomOpenSeaAsset() (Asset, error) {
 type downloadedOpenSeaAsset struct {
 	Id       string `json:"Id"`
 	Asset    `json:"Asset"`
-	Transaction `json:"Transaction"`
 	FileName string `json:"FileName"`
 }
 
 func (d downloadedOpenSeaAsset) GetUSDPrice() float64 {
-	return d.Transaction.Value * d.Asset.LastSale.TokenUSDPrice
+	return d.Asset.LastSale.TotalPrice * d.Asset.LastSale.PaymentToken.USDPrice
 }
 func (d downloadedOpenSeaAsset) IsVideo() bool {
 	return path.Ext(d.FileName) == ".mp4"
 }
 
-func downloadOpenSeaAsset(asset Asset, transaction Transaction) (string, error) {
+func downloadOpenSeaAsset(asset Asset) (string, error) {
 	id := getOpenSeaId(asset.Id)
 
 	u, err := url.Parse(asset.ImageUrl)
@@ -143,7 +142,6 @@ func downloadOpenSeaAsset(asset Asset, transaction Transaction) (string, error)
 	err = json.NewEncoder(jsonFile).Encode(downloadedOpenSeaAsset{
 		Id:       id,
 		Asset:    asset,
-		Transaction: transaction,
 		FileName: filename,
 	})
 	if err != nil {
@@ -190,15 +188,7 @@ func main() {
 		}
 		log.Println(asset)
 
-		transaction, err := GetTransaction(asset.LastSale.TransactionHash)
+		id, err := downloadOpenSeaAsset(asset)
-		if err != nil {
-			log.Println("Error consiguiendo transacción de Etherscan", err)
-			internalError(w, "Error hablandole a Etherscan.")
-			return
-		}
-		log.Println(transaction)
-
-		id, err := downloadOpenSeaAsset(asset, transaction)
 		if err != nil {
 			log.Println("Error descargando OpenSea asset", err)
 			internalError(w, "Error descargando NFT.")

opensea.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"encoding/json"
+	"math"
 	"net/http"
 	"strconv"
 )
@@ -17,8 +18,17 @@ type Asset struct {
 }
 
 type AssetLastSale struct {
-	TokenUSDPrice   float64
 	TransactionHash string
+	PaymentToken
+	// TotalPrice has 16 decimals trimmed off if PaymentToken.decimals > 16
+	TotalPrice float64
+}
+
+type PaymentToken struct {
+	Id       uint64
+	Symbol   string
+	USDPrice float64
+	Decimals int
 }
 
 // https://docs.opensea.io/reference/getting-assets
@@ -33,8 +43,12 @@ func GetAssets() (Assets, error) {
 			ImageUrl  string `json:"image_url"`
 			Name      string `json:"name"`
 			LastSale  struct {
+				TotalPrice   string `json:"total_price"`
 				PaymentToken struct {
+					Id       uint64 `json:"id"`
+					Symbol   string `json:"symbol"`
 					USDPrice string `json:"usd_price"`
+					Decimals int    `json:"decimals"`
 				} `json:"payment_token"`
 				Transaction struct {
 					Hash string `json:"transaction_hash"`
@@ -60,6 +74,17 @@ func GetAssets() (Assets, error) {
 		if err != nil {
 			return assets, err
 		}
+		trimmed := a.LastSale.TotalPrice
+		decimals := a.LastSale.PaymentToken.Decimals
+		if a.LastSale.PaymentToken.Decimals > 16 {
+			trimmed = trimmed[:len(trimmed)-16]
+			decimals = decimals - 16
+		}
+		totalprice, err := strconv.ParseFloat(trimmed, 64)
+		if err != nil {
+			return assets, err
+		}
+		totalprice = totalprice / math.Pow10(decimals)
 		assets = append(assets, Asset{
 			Id:        strconv.FormatUint(a.Id, 10),
 			TokenId:   a.TokenId,
@@ -67,7 +92,13 @@ func GetAssets() (Assets, error) {
 			ImageUrl:  a.ImageUrl,
 			Name:      a.Name,
 			LastSale: AssetLastSale{
-				TokenUSDPrice:   tokenUSDPrice,
+				TotalPrice: totalprice,
+				PaymentToken: PaymentToken{
+					Id:       a.LastSale.PaymentToken.Id,
+					Symbol:   a.LastSale.PaymentToken.Symbol,
+					Decimals: decimals,
+					USDPrice: tokenUSDPrice,
+				},
 				TransactionHash: a.LastSale.Transaction.Hash,
 			},
 		})