add Norges Bank exchange rates data source

2026-05-21 18:24:26 +08:00 · 2024-11-16 23:28:19 +08:00
parent 28908d81a3
commit 10e0972d79
5 changed files with 395 additions and 0 deletions
@@ -0,0 +1,178 @@
+package exchangerates
+
+import (
+	"encoding/xml"
+	"math"
+	"time"
+
+	"github.com/mayswind/ezbookkeeping/pkg/core"
+	"github.com/mayswind/ezbookkeeping/pkg/errs"
+	"github.com/mayswind/ezbookkeeping/pkg/log"
+	"github.com/mayswind/ezbookkeeping/pkg/models"
+	"github.com/mayswind/ezbookkeeping/pkg/utils"
+	"github.com/mayswind/ezbookkeeping/pkg/validators"
+)
+
+const norgesBankExchangeRateUrl = "https://data.norges-bank.no/api/data/EXR/B..NOK.SP?format=sdmx-compact-2.1&lastNObservations=1"
+const norgesBankExchangeRateReferenceUrl = "https://www.norges-bank.no/en/topics/Statistics/exchange_rates/"
+const norgesBankDataSource = "Norges Bank"
+const norgesBankBaseCurrency = "NOK"
+
+const norgesBankUpdateDateFormat = "2006-01-02 15"
+const norgesBankUpdateDateTimezone = "Europe/Oslo"
+
+// NorgesBankDataSource defines the structure of exchange rates data source of Norges Bank
+type NorgesBankDataSource struct {
+	ExchangeRatesDataSource
+}
+
+// NorgesBankExchangeRateData represents the whole data from Norges Bank
+type NorgesBankExchangeRateData struct {
+	XMLName xml.Name                       `xml:"StructureSpecificData"`
+	DataSet *NorgesBankExchangeRateDataSet `xml:"DataSet"`
+}
+
+// NorgesBankExchangeRateDataSet represents the dataset for exchange rates data of Norges Bank
+type NorgesBankExchangeRateDataSet struct {
+	ExchangeRates []*NorgesBankExchangeRate `xml:"Series"`
+}
+
+// NorgesBankExchangeRate represents the exchange rate data from Norges Bank
+type NorgesBankExchangeRate struct {
+	BaseCurrency   string                               `xml:"BASE_CUR,attr"`
+	TargetCurrency string                               `xml:"QUOTE_CUR,attr"`
+	UnitExponent   string                               `xml:"UNIT_MULT,attr"`
+	Observations   []*NorgesBankExchangeRateObservation `xml:"Obs"`
+}
+
+// NorgesBankExchangeRateObservation represents the observation data of exchange rate data from Norges Bank
+type NorgesBankExchangeRateObservation struct {
+	Date string `xml:"TIME_PERIOD,attr"`
+	Rate string `xml:"OBS_VALUE,attr"`
+}
+
+// ToLatestExchangeRateResponse returns a view-object according to original data from Norges Bank
+func (e *NorgesBankExchangeRateData) ToLatestExchangeRateResponse(c core.Context) *models.LatestExchangeRateResponse {
+	if e.DataSet == nil || len(e.DataSet.ExchangeRates) < 1 {
+		log.Errorf(c, "[norges_bank_datasource.ToLatestExchangeRateResponse] all exchange rates is empty")
+		return nil
+	}
+
+	timezone, err := time.LoadLocation(norgesBankUpdateDateTimezone)
+
+	if err != nil {
+		log.Errorf(c, "[norges_bank_datasource.ToLatestExchangeRateResponse] failed to get timezone, timezone name is %s", norgesBankUpdateDateTimezone)
+		return nil
+	}
+
+	exchangeRates := make(models.LatestExchangeRateSlice, 0, len(e.DataSet.ExchangeRates))
+	latestUpdateTime := int64(0)
+
+	for i := 0; i < len(e.DataSet.ExchangeRates); i++ {
+		exchangeRate := e.DataSet.ExchangeRates[i]
+
+		if _, exists := validators.AllCurrencyNames[exchangeRate.BaseCurrency]; !exists {
+			continue
+		}
+
+		if exchangeRate.TargetCurrency != norgesBankBaseCurrency {
+			continue
+		}
+
+		if len(exchangeRate.Observations) < 1 {
+			continue
+		}
+
+		updateDateTime := exchangeRate.Observations[0].Date + " 16" // Publication time of daily exchange rates is approximately 16:00 CET.
+		updateTime, err := time.ParseInLocation(norgesBankUpdateDateFormat, updateDateTime, timezone)
+
+		if err != nil {
+			log.Errorf(c, "[norges_bank_datasource.ToLatestExchangeRateResponse] failed to parse update date, datetime is %s", exchangeRate.Observations[0].Date)
+			return nil
+		}
+
+		if updateTime.Unix() > latestUpdateTime {
+			latestUpdateTime = updateTime.Unix()
+		}
+
+		finalExchangeRate := exchangeRate.ToLatestExchangeRate(c, exchangeRate.Observations[0].Rate)
+
+		if finalExchangeRate == nil {
+			continue
+		}
+
+		exchangeRates = append(exchangeRates, finalExchangeRate)
+	}
+
+	latestExchangeRateResp := &models.LatestExchangeRateResponse{
+		DataSource:    norgesBankDataSource,
+		ReferenceUrl:  norgesBankExchangeRateReferenceUrl,
+		UpdateTime:    latestUpdateTime,
+		BaseCurrency:  norgesBankBaseCurrency,
+		ExchangeRates: exchangeRates,
+	}
+
+	return latestExchangeRateResp
+}
+
+// ToLatestExchangeRate returns a data pair according to original data from Norges Bank
+func (e *NorgesBankExchangeRate) ToLatestExchangeRate(c core.Context, exchangeRate string) *models.LatestExchangeRate {
+	rate, err := utils.StringToFloat64(exchangeRate)
+
+	if err != nil {
+		log.Warnf(c, "[norges_bank_datasource.ToLatestExchangeRate] failed to parse rate, currency is %s, rate is %s", e.BaseCurrency, exchangeRate)
+		return nil
+	}
+
+	if rate <= 0 {
+		log.Warnf(c, "[norges_bank_datasource.ToLatestExchangeRate] rate is invalid, currency is %s, rate is %s", e.BaseCurrency, exchangeRate)
+		return nil
+	}
+
+	unitExponent, err := utils.StringToInt(e.UnitExponent)
+
+	if err != nil {
+		log.Warnf(c, "[norges_bank_datasource.ToLatestExchangeRate] failed to parse unit, currency is %s, unit exponent is %s", e.BaseCurrency, e.UnitExponent)
+		return nil
+	}
+
+	finalRate := 1 / rate
+
+	if unitExponent > 0 {
+		finalRate = finalRate / math.Pow10(-unitExponent)
+	}
+
+	if math.IsInf(finalRate, 0) {
+		return nil
+	}
+
+	return &models.LatestExchangeRate{
+		Currency: e.BaseCurrency,
+		Rate:     utils.Float64ToString(finalRate),
+	}
+}
+
+// GetRequestUrls returns the Norges Bank data source urls
+func (e *NorgesBankDataSource) GetRequestUrls() []string {
+	return []string{norgesBankExchangeRateUrl}
+}
+
+// Parse returns the common response entity according to the Norges Bank data source raw response
+func (e *NorgesBankDataSource) Parse(c core.Context, content []byte) (*models.LatestExchangeRateResponse, error) {
+	norgesBankData := &NorgesBankExchangeRateData{}
+	err := xml.Unmarshal(content, norgesBankData)
+
+	if err != nil {
+		log.Errorf(c, "[norges_bank_datasource.Parse] failed to parse xml data, content is %s, because %s", string(content), err.Error())
+		return nil, errs.ErrFailedToRequestRemoteApi
+	}
+
+	latestExchangeRateResponse := norgesBankData.ToLatestExchangeRateResponse(c)
+
+	if latestExchangeRateResponse == nil {
+		log.Errorf(c, "[norges_bank_datasource.Parse] failed to parse latest exchange rate data, content is %s", string(content))
+		return nil, errs.ErrFailedToRequestRemoteApi
+	}
+
+	return latestExchangeRateResponse, nil
+}