Golang : Get currencies exchange rates example
Problem :
You are building an e-commerce website/application and you want to display prices in certain currencies. You need to download latest currencies exchange rates. How to do that?
NOTE : It is good idea to store the rates into local database. It helps in situation when the connection to the external source is down and also consider speed in calculating the converted price
NOTE : Remember to execute the Golang program from cronjob to update rates on daily or hourly basis.
Solution :
Use data from http://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml(daily) or https://openexchangerates.org/api/latest.json (need API key to access). For this example, we will use the (daily) XML data from ECB. If you are looking for the historical data, see http://www.ecb.europa.eu/stats/eurofxref/eurofxref-hist-90d.xml
Here you go!
package main
import (
"encoding/xml"
"fmt"
"io/ioutil"
"log"
"net/http"
)
type Envelope struct {
Cube []struct {
Date string `xml:"time,attr"`
Rates []struct {
Currency string `xml:"currency,attr"`
Rate string `xml:"rate,attr"`
} `xml:"Cube"`
} `xml:"Cube>Cube"`
}
func main() {
// get the latest exchange rate
resp, err := http.Get("http://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml")
if err != nil {
log.Fatal(err)
}
defer resp.Body.Close()
xmlCurrenciesData, err := ioutil.ReadAll(resp.Body)
if err != nil {
log.Fatal(err)
}
var env Envelope
err = xml.Unmarshal(xmlCurrenciesData, &env)
if err != nil {
log.Fatal(err)
}
fmt.Println("Date ", env.Cube[0].Date)
for _, v := range env.Cube[0].Rates {
fmt.Println("Currency : ", v.Currency, " Rate : ", v.Rate)
}
// REMEMBER! this data is from European Central Bank
// therefore the rates are based on EUR
}
Sample output :
Date 2015-07-31
Currency : USD Rate : 1.0967
Currency : JPY Rate : 136.34
Currency : BGN Rate : 1.9558
Currency : CZK Rate : 27.031
Currency : DKK Rate : 7.4615
Currency : GBP Rate : 0.70410
Currency : HUF Rate : 308.30
Currency : PLN Rate : 4.1435
Currency : RON Rate : 4.4048
Currency : SEK Rate : 9.4622
Currency : CHF Rate : 1.0565
Currency : NOK Rate : 9.0015
Currency : HRK Rate : 7.5920
Currency : RUB Rate : 66.8596
Currency : TRY Rate : 3.0485
Currency : AUD Rate : 1.5140
Currency : BRL Rate : 3.6974
Currency : CAD Rate : 1.4310
Currency : CNY Rate : 6.8102
Currency : HKD Rate : 8.5032
Currency : IDR Rate : 14866.29
Currency : ILS Rate : 4.1440
Currency : INR Rate : 70.3382
Currency : KRW Rate : 1287.41
Currency : MXN Rate : 17.7473
Currency : MYR Rate : 4.2015
Currency : NZD Rate : 1.6769
Currency : PHP Rate : 50.146
Currency : SGD Rate : 1.5082
Currency : THB Rate : 38.571
Currency : ZAR Rate : 13.9210
See also : Golang : Get all countries currencies code in JSON format
By Adam Ng
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