code refactor

pkg/exchangerates/exchange_rates_datasource.go

@@ -1,14 +1,16 @@
 package exchangerates
 
 import (
+	"net/http"
+
 	"github.com/mayswind/ezbookkeeping/pkg/core"
 	"github.com/mayswind/ezbookkeeping/pkg/models"
 )
 
 // ExchangeRatesDataSource defines the structure of exchange rates data source
 type ExchangeRatesDataSource interface {
-	// GetRequestUrl returns the data source urls
-	GetRequestUrls() []string
+	// BuildRequests returns the http requests
+	BuildRequests() ([]*http.Request, error)
 
 	// Parse returns the common response entity according to the data source raw response
 	Parse(c core.Context, content []byte) (*models.LatestExchangeRateResponse, error)