String concatenation/conversion/formatting improvements (#393)

* Magic strings

* Comment, format and builder fixes

common/common.go

@@ -282,7 +282,7 @@ func GetURIPath(uri string) string {
 		return ""
 	}
 	if urip.RawQuery != "" {
-		return fmt.Sprintf("%s?%s", urip.Path, urip.RawQuery)
+		return urip.Path + "?" + urip.RawQuery
 	}
 	return urip.Path
 }

currency/forexprovider/currencylayer/currencylayer.go

@@ -13,7 +13,6 @@ package currencylayer
 
 import (
 	"errors"
-	"fmt"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -200,10 +199,10 @@ func (c *CurrencyLayer) SendHTTPRequest(endPoint string, values url.Values, resu
 
 	var auth bool
 	if c.APIKeyLvl == AccountFree {
-		path = fmt.Sprintf("%s%s%s", APIEndpointURL, endPoint, "?")
+		path = APIEndpointURL + endPoint + "?"
 	} else {
 		auth = true
-		path = fmt.Sprintf("%s%s%s", APIEndpointURLSSL, endPoint, "?")
+		path = APIEndpointURLSSL + endPoint + "?"
 	}
 	path += values.Encode()
 

exchanges/anx/anx_wrapper.go

@@ -1,7 +1,6 @@
 package anx
 
 import (
-	"fmt"
 	"strconv"
 	"strings"
 	"sync"
@@ -191,7 +190,9 @@ func (a *ANX) FetchTradablePairs(asset asset.Item) ([]string, error) {
 
 	var currencies []string
 	for x := range result.CurrencyPairs {
-		currencies = append(currencies, fmt.Sprintf("%v%v%v", result.CurrencyPairs[x].TradedCcy, a.GetPairFormat(asset, false).Delimiter, result.CurrencyPairs[x].SettlementCcy))
+		currencies = append(currencies, result.CurrencyPairs[x].TradedCcy+
+			a.GetPairFormat(asset, false).Delimiter+
+			result.CurrencyPairs[x].SettlementCcy)
 	}
 
 	return currencies, nil

exchanges/binance/binance.go

@@ -279,7 +279,7 @@ func (b *Binance) GetPriceChangeStats(symbol string) (PriceChangeStats, error) {
 // GetTickers returns the ticker data for the last 24 hrs
 func (b *Binance) GetTickers() ([]PriceChangeStats, error) {
 	var resp []PriceChangeStats
-	path := fmt.Sprintf("%s%s", b.API.Endpoints.URL, priceChange)
+	path := b.API.Endpoints.URL + priceChange
 	return resp, b.SendHTTPRequest(path, &resp)
 }
 
@@ -313,7 +313,7 @@ func (b *Binance) GetBestPrice(symbol string) (BestPrice, error) {
 func (b *Binance) NewOrder(o *NewOrderRequest) (NewOrderResponse, error) {
 	var resp NewOrderResponse
 
-	path := fmt.Sprintf("%s%s", b.API.Endpoints.URL, newOrder)
+	path := b.API.Endpoints.URL + newOrder
 
 	params := url.Values{}
 	params.Set("symbol", o.Symbol)
@@ -357,7 +357,7 @@ func (b *Binance) NewOrder(o *NewOrderRequest) (NewOrderResponse, error) {
 func (b *Binance) CancelExistingOrder(symbol string, orderID int64, origClientOrderID string) (CancelOrderResponse, error) {
 	var resp CancelOrderResponse
 
-	path := fmt.Sprintf("%s%s", b.API.Endpoints.URL, cancelOrder)
+	path := b.API.Endpoints.URL + cancelOrder
 
 	params := url.Values{}
 	params.Set("symbol", symbol)
@@ -379,7 +379,7 @@ func (b *Binance) CancelExistingOrder(symbol string, orderID int64, origClientOr
 func (b *Binance) OpenOrders(symbol string) ([]QueryOrderData, error) {
 	var resp []QueryOrderData
 
-	path := fmt.Sprintf("%s%s", b.API.Endpoints.URL, openOrders)
+	path := b.API.Endpoints.URL + openOrders
 
 	params := url.Values{}
 
@@ -400,7 +400,7 @@ func (b *Binance) OpenOrders(symbol string) ([]QueryOrderData, error) {
 func (b *Binance) AllOrders(symbol, orderID, limit string) ([]QueryOrderData, error) {
 	var resp []QueryOrderData
 
-	path := fmt.Sprintf("%s%s", b.API.Endpoints.URL, allOrders)
+	path := b.API.Endpoints.URL + allOrders
 
 	params := url.Values{}
 	params.Set("symbol", strings.ToUpper(symbol))
@@ -421,7 +421,7 @@ func (b *Binance) AllOrders(symbol, orderID, limit string) ([]QueryOrderData, er
 func (b *Binance) QueryOrder(symbol, origClientOrderID string, orderID int64) (QueryOrderData, error) {
 	var resp QueryOrderData
 
-	path := fmt.Sprintf("%s%s", b.API.Endpoints.URL, queryOrder)
+	path := b.API.Endpoints.URL + queryOrder
 
 	params := url.Values{}
 	params.Set("symbol", strings.ToUpper(symbol))
@@ -451,7 +451,7 @@ func (b *Binance) GetAccount() (*Account, error) {
 
 	var resp response
 
-	path := fmt.Sprintf("%s%s", b.API.Endpoints.URL, accountInfo)
+	path := b.API.Endpoints.URL + accountInfo
 	params := url.Values{}
 
 	if err := b.SendAuthHTTPRequest(http.MethodGet, path, params, &resp); err != nil {
@@ -503,7 +503,7 @@ func (b *Binance) SendAuthHTTPRequest(method, path string, params url.Values, re
 	}
 
 	path = common.EncodeURLValues(path, params)
-	path += fmt.Sprintf("&signature=%s", hmacSignedStr)
+	path += "&signature=" + hmacSignedStr
 
 	interim := json.RawMessage{}
 
@@ -643,7 +643,7 @@ func getCryptocurrencyWithdrawalFee(c currency.Code) float64 {
 // WithdrawCrypto sends cryptocurrency to the address of your choosing
 func (b *Binance) WithdrawCrypto(asset, address, addressTag, name, amount string) (string, error) {
 	var resp WithdrawResponse
-	path := fmt.Sprintf("%s%s", b.API.Endpoints.URL, withdraw)
+	path := b.API.Endpoints.URL + withdraw
 
 	params := url.Values{}
 	params.Set("asset", asset)
@@ -669,7 +669,7 @@ func (b *Binance) WithdrawCrypto(asset, address, addressTag, name, amount string
 
 // GetDepositAddressForCurrency retrieves the wallet address for a given currency
 func (b *Binance) GetDepositAddressForCurrency(currency string) (string, error) {
-	path := fmt.Sprintf("%s%s", b.API.Endpoints.URL, depositAddress)
+	path := b.API.Endpoints.URL + depositAddress
 
 	resp := struct {
 		Address    string `json:"address"`

exchanges/binance/binance_wrapper.go

@@ -231,10 +231,9 @@ func (b *Binance) FetchTradablePairs(asset asset.Item) ([]string, error) {
 
 	for x := range info.Symbols {
 		if info.Symbols[x].Status == "TRADING" {
-			validCurrencyPairs = append(validCurrencyPairs, fmt.Sprintf("%v%v%v",
-				info.Symbols[x].BaseAsset,
-				b.GetPairFormat(asset, false).Delimiter,
-				info.Symbols[x].QuoteAsset))
+			validCurrencyPairs = append(validCurrencyPairs, info.Symbols[x].BaseAsset+
+				b.GetPairFormat(asset, false).Delimiter+
+				info.Symbols[x].QuoteAsset)
 		}
 	}
 	return validCurrencyPairs, nil

exchanges/bitfinex/bitfinex.go

@@ -948,7 +948,7 @@ func (b *Bitfinex) SendAuthenticatedHTTPRequest(method, path string, params map[
 	n := b.Requester.GetNonce(true)
 
 	req := make(map[string]interface{})
-	req["request"] = fmt.Sprintf("%s%s", bitfinexAPIVersion, path)
+	req["request"] = bitfinexAPIVersion + path
 	req["nonce"] = n.String()
 
 	for key, value := range params {

exchanges/bitfinex/bitfinex_types.go

@@ -620,7 +620,7 @@ type WsMarginInfoBase struct {
 	MarginNet      float64
 }
 
-// WsMarginInfoBase recent funding trades received via websocket
+// WsFundingTrade recent funding trades received via websocket
 type WsFundingTrade struct {
 	ID         int64
 	Symbol     string

exchanges/bitfinex/bitfinex_wrapper.go

@@ -2,7 +2,6 @@ package bitfinex
 
 import (
 	"errors"
-	"fmt"
 	"net/url"
 	"strconv"
 	"strings"
@@ -524,21 +523,20 @@ func (b *Bitfinex) WithdrawFiatFunds(withdrawRequest *exchange.FiatWithdrawReque
 		return "", errors.New("no withdrawID returned. Check order status")
 	}
 
-	var withdrawalSuccesses string
-	var withdrawalErrors string
-	for _, withdrawal := range resp {
-		if withdrawal.Status == "error" {
-			withdrawalErrors += fmt.Sprintf("%v ", withdrawal.Message)
+	var withdrawalSuccesses, withdrawalErrors strings.Builder
+	for x := range resp {
+		if resp[x].Status == "error" {
+			withdrawalErrors.WriteString(resp[x].Message + " ")
 		}
-		if withdrawal.Status == "success" {
-			withdrawalSuccesses += fmt.Sprintf("%v,", withdrawal.WithdrawalID)
+		if resp[x].Status == "success" {
+			withdrawalSuccesses.WriteString(strconv.FormatInt(resp[x].WithdrawalID, 10) + ",")
 		}
 	}
-	if len(withdrawalErrors) > 0 {
-		return withdrawalSuccesses, errors.New(withdrawalErrors)
+	if withdrawalErrors.Len() > 0 {
+		return withdrawalSuccesses.String(), errors.New(withdrawalErrors.String())
 	}
 
-	return withdrawalSuccesses, nil
+	return withdrawalSuccesses.String(), nil
 }
 
 // WithdrawFiatFundsToInternationalBank returns a withdrawal ID when a withdrawal is submitted

exchanges/bitflyer/bitflyer.go

@@ -74,8 +74,7 @@ type Bitflyer struct {
 // analysis system
 func (b *Bitflyer) GetLatestBlockCA() (ChainAnalysisBlock, error) {
 	var resp ChainAnalysisBlock
-	path := fmt.Sprintf("%s%s", b.API.Endpoints.URLSecondary, latestBlock)
-
+	path := b.API.Endpoints.URLSecondary + latestBlock
 	return resp, b.SendHTTPRequest(path, &resp)
 }
 
@@ -83,8 +82,7 @@ func (b *Bitflyer) GetLatestBlockCA() (ChainAnalysisBlock, error) {
 // analysis system
 func (b *Bitflyer) GetBlockCA(blockhash string) (ChainAnalysisBlock, error) {
 	var resp ChainAnalysisBlock
-	path := fmt.Sprintf("%s%s%s", b.API.Endpoints.URLSecondary, blockByBlockHash, blockhash)
-
+	path := b.API.Endpoints.URLSecondary + blockByBlockHash + blockhash
 	return resp, b.SendHTTPRequest(path, &resp)
 }
 
@@ -92,8 +90,9 @@ func (b *Bitflyer) GetBlockCA(blockhash string) (ChainAnalysisBlock, error) {
 // analysis system
 func (b *Bitflyer) GetBlockbyHeightCA(height int64) (ChainAnalysisBlock, error) {
 	var resp ChainAnalysisBlock
-	path := fmt.Sprintf("%s%s%s", b.API.Endpoints.URLSecondary, blockByBlockHeight, strconv.FormatInt(height, 10))
-
+	path := b.API.Endpoints.URLSecondary +
+		blockByBlockHeight +
+		strconv.FormatInt(height, 10)
 	return resp, b.SendHTTPRequest(path, &resp)
 }
 
@@ -101,8 +100,7 @@ func (b *Bitflyer) GetBlockbyHeightCA(height int64) (ChainAnalysisBlock, error)
 // bitflyer chain analysis system
 func (b *Bitflyer) GetTransactionByHashCA(txHash string) (ChainAnalysisTransaction, error) {
 	var resp ChainAnalysisTransaction
-	path := fmt.Sprintf("%s%s%s", b.API.Endpoints.URLSecondary, transaction, txHash)
-
+	path := b.API.Endpoints.URLSecondary + transaction + txHash
 	return resp, b.SendHTTPRequest(path, &resp)
 }
 
@@ -110,7 +108,7 @@ func (b *Bitflyer) GetTransactionByHashCA(txHash string) (ChainAnalysisTransacti
 // from bitflyer chain analysis system
 func (b *Bitflyer) GetAddressInfoCA(addressln string) (ChainAnalysisAddress, error) {
 	var resp ChainAnalysisAddress
-	path := fmt.Sprintf("%s%s%s", b.API.Endpoints.URLSecondary, address, addressln)
+	path := b.API.Endpoints.URLSecondary + address + addressln
 
 	return resp, b.SendHTTPRequest(path, &resp)
 }
@@ -118,7 +116,7 @@ func (b *Bitflyer) GetAddressInfoCA(addressln string) (ChainAnalysisAddress, err
 // GetMarkets returns market information
 func (b *Bitflyer) GetMarkets() ([]MarketInfo, error) {
 	var resp []MarketInfo
-	path := fmt.Sprintf("%s%s", b.API.Endpoints.URL, pubGetMarkets)
+	path := b.API.Endpoints.URL + pubGetMarkets
 
 	return resp, b.SendHTTPRequest(path, &resp)
 }
@@ -139,7 +137,6 @@ func (b *Bitflyer) GetTicker(symbol string) (Ticker, error) {
 	v := url.Values{}
 	v.Set("product_code", symbol)
 	path := fmt.Sprintf("%s%s?%s", b.API.Endpoints.URL, pubGetTicker, v.Encode())
-
 	return resp, b.SendHTTPRequest(path, &resp)
 }
 
@@ -157,7 +154,7 @@ func (b *Bitflyer) GetExecutionHistory(symbol string) ([]ExecutedTrade, error) {
 func (b *Bitflyer) GetExchangeStatus() (string, error) {
 	resp := make(map[string]string)
 
-	path := fmt.Sprintf("%s%s", b.API.Endpoints.URL, pubGetHealth)
+	path := b.API.Endpoints.URL + pubGetHealth
 
 	err := b.SendHTTPRequest(path, &resp)
 	if err != nil {

exchanges/bithumb/bithumb.go

@@ -74,10 +74,9 @@ func (b *Bithumb) GetTradablePairs() ([]string, error) {
 // symbol e.g. "btc"
 func (b *Bithumb) GetTicker(symbol string) (Ticker, error) {
 	var response TickerResponse
-	path := fmt.Sprintf("%s%s%s",
-		b.API.Endpoints.URL,
-		publicTicker,
-		strings.ToUpper(symbol))
+	path := b.API.Endpoints.URL +
+		publicTicker +
+		strings.ToUpper(symbol)
 	err := b.SendHTTPRequest(path, &response)
 	if err != nil {
 		return response.Data, err
@@ -93,7 +92,7 @@ func (b *Bithumb) GetTicker(symbol string) (Ticker, error) {
 // GetAllTickers returns all ticker information
 func (b *Bithumb) GetAllTickers() (map[string]Ticker, error) {
 	var response TickersResponse
-	path := fmt.Sprintf("%s%s%s", b.API.Endpoints.URL, publicTicker, "all")
+	path := b.API.Endpoints.URL + publicTicker + "all"
 	err := b.SendHTTPRequest(path, &response)
 	if err != nil {
 		return nil, err
@@ -123,7 +122,7 @@ func (b *Bithumb) GetAllTickers() (map[string]Ticker, error) {
 // symbol e.g. "btc"
 func (b *Bithumb) GetOrderBook(symbol string) (Orderbook, error) {
 	response := Orderbook{}
-	path := fmt.Sprintf("%s%s%s", b.API.Endpoints.URL, publicOrderBook, strings.ToUpper(symbol))
+	path := b.API.Endpoints.URL + publicOrderBook + strings.ToUpper(symbol)
 
 	err := b.SendHTTPRequest(path, &response)
 	if err != nil {
@@ -142,7 +141,9 @@ func (b *Bithumb) GetOrderBook(symbol string) (Orderbook, error) {
 // symbol e.g. "btc"
 func (b *Bithumb) GetTransactionHistory(symbol string) (TransactionHistory, error) {
 	response := TransactionHistory{}
-	path := fmt.Sprintf("%s%s%s", b.API.Endpoints.URL, publicTransactionHistory, strings.ToUpper(symbol))
+	path := b.API.Endpoints.URL +
+		publicTransactionHistory +
+		strings.ToUpper(symbol)
 
 	err := b.SendHTTPRequest(path, &response)
 	if err != nil {

exchanges/bithumb/bithumb_wrapper.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"math"
+	"strconv"
 	"sync"
 	"time"
 
@@ -423,7 +424,8 @@ func (b *Bithumb) WithdrawFiatFunds(withdrawRequest *exchange.FiatWithdrawReques
 	if withdrawRequest.Currency != currency.KRW {
 		return "", errors.New("only KRW is supported")
 	}
-	bankDetails := fmt.Sprintf("%v_%v", withdrawRequest.BankCode, withdrawRequest.BankName)
+	bankDetails := strconv.FormatFloat(withdrawRequest.BankCode, 'f', -1, 64) +
+		"_" + withdrawRequest.BankName
 	resp, err := b.RequestKRWWithdraw(bankDetails, withdrawRequest.BankAccountNumber, int64(withdrawRequest.Amount))
 	if err != nil {
 		return "", err

exchanges/bitmex/bitmex.go

@@ -327,9 +327,8 @@ func (b *Bitmex) GetCurrentNotifications() ([]Notification, error) {
 // GetOrders returns all the orders, open and closed
 func (b *Bitmex) GetOrders(params *OrdersRequest) ([]Order, error) {
 	var orders []Order
-
 	return orders, b.SendAuthenticatedHTTPRequest(http.MethodGet,
-		fmt.Sprintf("%v%v", bitmexEndpointOrder, ""),
+		bitmexEndpointOrder,
 		params,
 		&orders)
 }

exchanges/bitmex/bitmex_websocket.go

@@ -434,7 +434,7 @@ func (b *Bitmex) GenerateDefaultSubscriptions() {
 	for i := range channels {
 		for j := range allPairs {
 			subscriptions = append(subscriptions, wshandler.WebsocketChannelSubscription{
-				Channel:  fmt.Sprintf("%v:%v", channels[i], allPairs[j].String()),
+				Channel:  channels[i] + ":" + allPairs[j].String(),
 				Currency: allPairs[j],
 			})
 		}
@@ -474,7 +474,7 @@ func (b *Bitmex) GenerateAuthenticatedSubscriptions() {
 	for i := range channels {
 		for j := range contracts {
 			subscriptions = append(subscriptions, wshandler.WebsocketChannelSubscription{
-				Channel:  fmt.Sprintf("%v:%v", channels[i], contracts[j].String()),
+				Channel:  channels[i] + ":" + contracts[j].String(),
 				Currency: contracts[j],
 			})
 		}

exchanges/bitstamp/bitstamp.go

@@ -681,11 +681,11 @@ func (b *Bitstamp) SendAuthenticatedHTTPRequest(path string, v2 bool, values url
 			return errors.New(errCap.Error)
 		}
 		if data, ok := errCap.Reason.(map[string][]string); ok {
-			var details string
-			for _, v := range data {
-				details += strings.Join(v, "")
+			var details strings.Builder
+			for x := range data {
+				details.WriteString(strings.Join(data[x], ""))
 			}
-			return errors.New(details)
+			return errors.New(details.String())
 		}
 
 		if data, ok := errCap.Reason.(string); ok {

exchanges/bitstamp/bitstamp_websocket.go

@@ -3,7 +3,6 @@ package bitstamp
 import (
 	"encoding/json"
 	"errors"
-	"fmt"
 	"net/http"
 	"strconv"
 	"strings"
@@ -128,7 +127,7 @@ func (b *Bitstamp) generateDefaultSubscriptions() {
 	for i := range channels {
 		for j := range enabledCurrencies {
 			subscriptions = append(subscriptions, wshandler.WebsocketChannelSubscription{
-				Channel: fmt.Sprintf("%v%v", channels[i], enabledCurrencies[j].Lower().String()),
+				Channel: channels[i] + enabledCurrencies[j].Lower().String(),
 			})
 		}
 	}

exchanges/bitstamp/bitstamp_wrapper.go

@@ -430,11 +430,11 @@ func (b *Bitstamp) WithdrawCryptocurrencyFunds(withdrawRequest *exchange.CryptoW
 		return "", err
 	}
 	if len(resp.Error) != 0 {
-		var details string
-		for _, v := range resp.Error {
-			details += strings.Join(v, "")
+		var details strings.Builder
+		for x := range resp.Error {
+			details.WriteString(strings.Join(resp.Error[x], ""))
 		}
-		return "", errors.New(details)
+		return "", errors.New(details.String())
 	}
 
 	return resp.ID, nil
@@ -458,11 +458,11 @@ func (b *Bitstamp) WithdrawFiatFunds(withdrawRequest *exchange.FiatWithdrawReque
 		return "", err
 	}
 	if resp.Status == errStr {
-		var details string
-		for _, v := range resp.Reason {
-			details += strings.Join(v, "")
+		var details strings.Builder
+		for x := range resp.Reason {
+			details.WriteString(strings.Join(resp.Reason[x], ""))
 		}
-		return "", errors.New(details)
+		return "", errors.New(details.String())
 	}
 
 	return resp.ID, nil
@@ -492,11 +492,11 @@ func (b *Bitstamp) WithdrawFiatFundsToInternationalBank(withdrawRequest *exchang
 		return "", err
 	}
 	if resp.Status == errStr {
-		var details string
-		for _, v := range resp.Reason {
-			details += strings.Join(v, "")
+		var details strings.Builder
+		for x := range resp.Reason {
+			details.WriteString(strings.Join(resp.Reason[x], ""))
 		}
-		return "", errors.New(details)
+		return "", errors.New(details.String())
 	}
 
 	return resp.ID, nil

exchanges/coinbasepro/coinbasepro_wrapper.go

@@ -233,8 +233,9 @@ func (c *CoinbasePro) FetchTradablePairs(asset asset.Item) ([]string, error) {
 
 	var products []string
 	for x := range pairs {
-		products = append(products, fmt.Sprintf("%s%s%s", pairs[x].BaseCurrency,
-			c.GetPairFormat(asset, false).Delimiter, pairs[x].QuoteCurrency))
+		products = append(products, pairs[x].BaseCurrency+
+			c.GetPairFormat(asset, false).Delimiter+
+			pairs[x].QuoteCurrency)
 	}
 
 	return products, nil

exchanges/coinut/coinut_websocket.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"strconv"
 	"strings"
 	"time"
 
@@ -377,7 +378,9 @@ func (c *COINUT) wsAuthenticate() error {
 	}
 	timestamp := time.Now().Unix()
 	nonce := c.WebsocketConn.GenerateMessageID(false)
-	payload := fmt.Sprintf("%v|%v|%v", c.API.Credentials.ClientID, timestamp, nonce)
+	payload := c.API.Credentials.ClientID + "|" +
+		strconv.FormatInt(timestamp, 10) + "|" +
+		strconv.FormatInt(nonce, 10)
 	hmac := crypto.GetHMAC(crypto.HashSHA256, []byte(payload), []byte(c.API.Credentials.Key))
 	loginRequest := struct {
 		Request   string `json:"request"`

exchanges/exchange.go

@@ -362,21 +362,21 @@ func (e *Base) SupportsPair(p currency.Pair, enabledPairs bool, assetType asset.
 // FormatExchangeCurrencies returns a string containing
 // the exchanges formatted currency pairs
 func (e *Base) FormatExchangeCurrencies(pairs []currency.Pair, assetType asset.Item) (string, error) {
-	var currencyItems string
+	var currencyItems strings.Builder
 	pairFmt := e.GetPairFormat(assetType, true)
 
 	for x := range pairs {
-		currencyItems += e.FormatExchangeCurrency(pairs[x], assetType).String()
+		currencyItems.WriteString(e.FormatExchangeCurrency(pairs[x], assetType).String())
 		if x == len(pairs)-1 {
 			continue
 		}
-		currencyItems += pairFmt.Separator
+		currencyItems.WriteString(pairFmt.Separator)
 	}
 
-	if currencyItems == "" {
+	if currencyItems.Len() == 0 {
 		return "", errors.New("returned empty string")
 	}
-	return currencyItems, nil
+	return currencyItems.String(), nil
 }
 
 // FormatExchangeCurrency is a method that formats and returns a currency pair

exchanges/exmo/exmo.go

@@ -210,12 +210,9 @@ func (e *EXMO) GetCryptoDepositAddress() (map[string]string, error) {
 	switch r := result.(type) {
 	case map[string]interface{}:
 		mapString := make(map[string]string)
-
 		for key, value := range r {
-			strValue := fmt.Sprintf("%v", value)
-			mapString[key] = strValue
+			mapString[key] = value.(string)
 		}
-
 		return mapString, nil
 
 	default:

exchanges/gemini/gemini_websocket.go

@@ -104,7 +104,7 @@ func (g *Gemini) WsSecureSubscribe(dialer *websocket.Dialer, url string) error {
 		return fmt.Errorf("%v sendAuthenticatedHTTPRequest: Unable to JSON request", g.Name)
 	}
 
-	endpoint := fmt.Sprintf("%v%v", g.API.Endpoints.WebsocketURL, url)
+	endpoint := g.API.Endpoints.WebsocketURL + url
 	PayloadBase64 := crypto.Base64Encode(PayloadJSON)
 	hmac := crypto.GetHMAC(crypto.HashSHA512_384, []byte(PayloadBase64), []byte(g.API.Credentials.Secret))
 	headers := http.Header{}

exchanges/hitbtc/hitbtc_wrapper.go

@@ -222,8 +222,8 @@ func (h *HitBTC) FetchTradablePairs(asset asset.Item) ([]string, error) {
 
 	var pairs []string
 	for x := range symbols {
-		pairs = append(pairs, fmt.Sprintf("%v%v%v", symbols[x].BaseCurrency,
-			h.GetPairFormat(asset, false).Delimiter, symbols[x].QuoteCurrency))
+		pairs = append(pairs, symbols[x].BaseCurrency+
+			h.GetPairFormat(asset, false).Delimiter+symbols[x].QuoteCurrency)
 	}
 	return pairs, nil
 }

exchanges/huobi/huobi_wrapper.go

@@ -267,10 +267,9 @@ func (h *HUOBI) FetchTradablePairs(asset asset.Item) ([]string, error) {
 		if symbols[x].State != "online" {
 			continue
 		}
-		pairs = append(pairs, fmt.Sprintf("%v%v%v",
-			symbols[x].BaseCurrency,
-			h.GetPairFormat(asset, false).Delimiter,
-			symbols[x].QuoteCurrency))
+		pairs = append(pairs, symbols[x].BaseCurrency+
+			h.GetPairFormat(asset, false).Delimiter+
+			symbols[x].QuoteCurrency)
 	}
 
 	return pairs, nil

exchanges/kraken/kraken.go

@@ -1039,6 +1039,7 @@ func (k *Kraken) WithdrawCancel(c currency.Code, refID string) (bool, error) {
 	return response.Result, GetError(response.Error)
 }
 
+// GetWebsocketToken returns a websocket token
 func (k *Kraken) GetWebsocketToken() (string, error) {
 	var response WsTokenResponse
 	if err := k.SendAuthenticatedHTTPRequest(krakenWebsocketToken, url.Values{}, &response); err != nil {

exchanges/kraken/kraken_websocket.go

@@ -849,7 +849,7 @@ func (k *Kraken) GenerateDefaultSubscriptions() {
 	k.Websocket.SubscribeToChannels(subscriptions)
 }
 
-// GenerateDefaultSubscriptions Adds default subscriptions to websocket to be handled by ManageSubscriptions()
+// GenerateAuthenticatedSubscriptions Adds default subscriptions to websocket to be handled by ManageSubscriptions()
 func (k *Kraken) GenerateAuthenticatedSubscriptions() {
 	var subscriptions []wshandler.WebsocketChannelSubscription
 	for i := range authenticatedChannels {

exchanges/kraken/kraken_wrapper.go

@@ -260,10 +260,9 @@ func (k *Kraken) FetchTradablePairs(asset asset.Item) ([]string, error) {
 		if v.Quote[0] == 'Z' || v.Quote[0] == 'X' {
 			v.Quote = v.Quote[1:]
 		}
-		products = append(products, fmt.Sprintf("%v%v%v",
-			v.Base,
-			k.GetPairFormat(asset, false).Delimiter,
-			v.Quote))
+		products = append(products, v.Base+
+			k.GetPairFormat(asset, false).Delimiter+
+			v.Quote)
 	}
 	return products, nil
 }

exchanges/lakebtc/lakebtc_test.go

@@ -1,7 +1,6 @@
 package lakebtc
 
 import (
-	"fmt"
 	"log"
 	"os"
 	"testing"
@@ -474,7 +473,7 @@ func TestWsTickerProcessing(t *testing.T) {
 
 func TestGetCurrencyFromChannel(t *testing.T) {
 	curr := currency.NewPair(currency.LTC, currency.BTC)
-	result := l.getCurrencyFromChannel(fmt.Sprintf("%v%v%v", marketSubstring, curr, globalSubstring))
+	result := l.getCurrencyFromChannel(marketSubstring + curr.String() + globalSubstring)
 	if curr != result {
 		t.Errorf("currency result is not equal. Expected  %v", curr)
 	}

exchanges/lakebtc/lakebtc_websocket.go

@@ -76,10 +76,9 @@ func (l *LakeBTC) GenerateDefaultSubscriptions() {
 
 	for j := range enabledCurrencies {
 		enabledCurrencies[j].Delimiter = ""
-		channel := fmt.Sprintf("%v%v%v",
-			marketSubstring,
-			enabledCurrencies[j].Lower(),
-			globalSubstring)
+		channel := marketSubstring +
+			enabledCurrencies[j].Lower().String() +
+			globalSubstring
 
 		subscriptions = append(subscriptions, wshandler.WebsocketChannelSubscription{
 			Channel:  channel,

exchanges/localbitcoins/localbitcoins.go

@@ -601,11 +601,11 @@ func (l *LocalBitcoins) WalletSend(address string, amount float64, pin int64) er
 
 	if resp.Data.Message != "Money is being sent" {
 		if len(resp.Error.Errors) != 0 {
-			var details string
-			for _, val := range resp.Error.Errors {
-				details += val
+			var details strings.Builder
+			for x := range resp.Error.Errors {
+				details.WriteString(resp.Error.Errors[x])
 			}
-			return errors.New(details)
+			return errors.New(details.String())
 		}
 		return errors.New(resp.Data.Message)
 	}

exchanges/okcoin/okcoin_wrapper.go

@@ -194,8 +194,9 @@ func (o *OKCoin) FetchTradablePairs(asset asset.Item) ([]string, error) {
 
 	var pairs []string
 	for x := range prods {
-		pairs = append(pairs, fmt.Sprintf("%v%v%v", prods[x].BaseCurrency,
-			o.GetPairFormat(asset, false).Delimiter, prods[x].QuoteCurrency))
+		pairs = append(pairs, prods[x].BaseCurrency+
+			o.GetPairFormat(asset, false).Delimiter+
+			prods[x].QuoteCurrency)
 	}
 
 	return pairs, nil

exchanges/okgroup/okgroup_websocket.go

@@ -670,23 +670,23 @@ func (o *OKGroup) WsProcessUpdateOrderbook(wsEventData *WebsocketDataWrapper, in
 // there are less than 25 entries (for whatever reason)
 // eg Bid:Ask:Bid:Ask:Ask:Ask
 func (o *OKGroup) CalculatePartialOrderbookChecksum(orderbookData *WebsocketDataWrapper) int32 {
-	var checksum string
+	var checksum strings.Builder
 	for i := 0; i < allowableIterations; i++ {
 		if len(orderbookData.Bids)-1 >= i {
-			checksum += orderbookData.Bids[i][0].(string) +
+			checksum.WriteString(orderbookData.Bids[i][0].(string) +
 				delimiterColon +
 				orderbookData.Bids[i][1].(string) +
-				delimiterColon
+				delimiterColon)
 		}
 		if len(orderbookData.Asks)-1 >= i {
-			checksum += orderbookData.Asks[i][0].(string) +
+			checksum.WriteString(orderbookData.Asks[i][0].(string) +
 				delimiterColon +
 				orderbookData.Asks[i][1].(string) +
-				delimiterColon
+				delimiterColon)
 		}
 	}
-	checksum = strings.TrimSuffix(checksum, delimiterColon)
-	return int32(crc32.ChecksumIEEE([]byte(checksum)))
+	checksumStr := strings.TrimSuffix(checksum.String(), delimiterColon)
+	return int32(crc32.ChecksumIEEE([]byte(checksumStr)))
 }
 
 // CalculateUpdateOrderbookChecksum alternates over the first 25 bid and ask
@@ -695,21 +695,21 @@ func (o *OKGroup) CalculatePartialOrderbookChecksum(orderbookData *WebsocketData
 // there are less than 25 entries (for whatever reason)
 // eg Bid:Ask:Bid:Ask:Ask:Ask
 func (o *OKGroup) CalculateUpdateOrderbookChecksum(orderbookData *orderbook.Base) int32 {
-	var checksum string
+	var checksum strings.Builder
 	for i := 0; i < allowableIterations; i++ {
 		if len(orderbookData.Bids)-1 >= i {
 			price := strconv.FormatFloat(orderbookData.Bids[i].Price, 'f', -1, 64)
 			amount := strconv.FormatFloat(orderbookData.Bids[i].Amount, 'f', -1, 64)
-			checksum += price + delimiterColon + amount + delimiterColon
+			checksum.WriteString(price + delimiterColon + amount + delimiterColon)
 		}
 		if len(orderbookData.Asks)-1 >= i {
 			price := strconv.FormatFloat(orderbookData.Asks[i].Price, 'f', -1, 64)
 			amount := strconv.FormatFloat(orderbookData.Asks[i].Amount, 'f', -1, 64)
-			checksum += price + delimiterColon + amount + delimiterColon
+			checksum.WriteString(price + delimiterColon + amount + delimiterColon)
 		}
 	}
-	checksum = strings.TrimSuffix(checksum, delimiterColon)
-	return int32(crc32.ChecksumIEEE([]byte(checksum)))
+	checksumStr := strings.TrimSuffix(checksum.String(), delimiterColon)
+	return int32(crc32.ChecksumIEEE([]byte(checksumStr)))
 }
 
 // GenerateDefaultSubscriptions Adds default subscriptions to websocket to be

exchanges/zb/zb_websocket.go

@@ -377,7 +377,7 @@ func (z *ZB) wsSubmitOrder(pair currency.Pair, amount, price float64, tradeType
 		TradeType: tradeType,
 		No:        z.WebsocketConn.GenerateMessageID(true),
 	}
-	request.Channel = fmt.Sprintf("%v_order", pair.String())
+	request.Channel = pair.String() + "_order"
 	request.Event = zWebsocketAddChannel
 	request.Accesskey = z.API.Credentials.Key
 	request.Sign = z.wsGenerateSignature(request)
@@ -405,7 +405,7 @@ func (z *ZB) wsCancelOrder(pair currency.Pair, orderID int64) (*WsCancelOrderRes
 		ID: orderID,
 		No: z.WebsocketConn.GenerateMessageID(true),
 	}
-	request.Channel = fmt.Sprintf("%v_cancelorder", pair.String())
+	request.Channel = pair.String() + "_cancelorder"
 	request.Event = zWebsocketAddChannel
 	request.Accesskey = z.API.Credentials.Key
 	request.Sign = z.wsGenerateSignature(request)
@@ -433,7 +433,7 @@ func (z *ZB) wsGetOrder(pair currency.Pair, orderID int64) (*WsGetOrderResponse,
 		ID: orderID,
 		No: z.WebsocketConn.GenerateMessageID(true),
 	}
-	request.Channel = fmt.Sprintf("%v_getorder", pair.String())
+	request.Channel = pair.String() + "_getorder"
 	request.Event = zWebsocketAddChannel
 	request.Accesskey = z.API.Credentials.Key
 	request.Sign = z.wsGenerateSignature(request)
@@ -462,7 +462,7 @@ func (z *ZB) wsGetOrders(pair currency.Pair, pageIndex, tradeType int64) (*WsGet
 		TradeType: tradeType,
 		No:        z.WebsocketConn.GenerateMessageID(true),
 	}
-	request.Channel = fmt.Sprintf("%v_getorders", pair.String())
+	request.Channel = pair.String() + "_getorders"
 	request.Event = zWebsocketAddChannel
 	request.Accesskey = z.API.Credentials.Key
 	request.Sign = z.wsGenerateSignature(request)
@@ -490,7 +490,7 @@ func (z *ZB) wsGetOrdersIgnoreTradeType(pair currency.Pair, pageIndex, pageSize
 		PageSize:  pageSize,
 		No:        z.WebsocketConn.GenerateMessageID(true),
 	}
-	request.Channel = fmt.Sprintf("%v_getordersignoretradetype", pair.String())
+	request.Channel = pair.String() + "_getordersignoretradetype"
 	request.Event = zWebsocketAddChannel
 	request.Accesskey = z.API.Credentials.Key
 	request.Sign = z.wsGenerateSignature(request)