add National Bank of Poland exchange rate data source

conf/lab.ini

@@ -111,7 +111,7 @@ enable_register = true
 enable_export = true
 
 [exchange_rates]
-# Exchange rates data source, supports "euro_central_bank", "czech_national_bank" currently
+# Exchange rates data source, supports "euro_central_bank", "czech_national_bank", "national_bank_of_poland" currently
 data_source = euro_central_bank
 
 # Requesting exchange rates data timeout (milliseconds), default is 10000 (10 seconds)

pkg/exchangerates/exchange_rates_datasource_container.go

@@ -23,6 +23,9 @@ func InitializeExchangeRatesDataSource(config *settings.Config) error {
 	} else if config.ExchangeRatesDataSource == settings.CzechNationalBankDataSource {
 		Container.Current = &CzechNationalBankDataSource{}
 		return nil
+	} else if config.ExchangeRatesDataSource == settings.NationalBankOfPolandDataSource {
+		Container.Current = &NationalBankOfPolandDataSource{}
+		return nil
 	}
 
 	return errs.ErrInvalidExchangeRatesDataSource

pkg/exchangerates/national_bank_of_poland_datasource.go

@@ -0,0 +1,155 @@
+package exchangerates
+
+import (
+	"bytes"
+	"encoding/xml"
+	"math"
+	"time"
+
+	"github.com/mayswind/lab/pkg/core"
+	"github.com/mayswind/lab/pkg/errs"
+	"github.com/mayswind/lab/pkg/log"
+	"github.com/mayswind/lab/pkg/models"
+	"github.com/mayswind/lab/pkg/utils"
+	"github.com/mayswind/lab/pkg/validators"
+)
+
+const nationalBankOfPolandDailyExchangeRateUrl = "https://www.nbp.pl/kursy/xml/en/lastaen.xml"
+const nationalBankOfPolandInconvertibleCurrencyExchangeRateUrl = "https://www.nbp.pl/kursy/xml/en/lastben.xml"
+const nationalBankOfPolandExchangeRateReferenceUrl = "https://www.nbp.pl/homen.aspx?f=/kursy/kursyen.htm"
+const nationalBankOfPolandDataSource = "Narodowy Bank Polski"
+const nationalBankOfPolandBaseCurrency = "PLN"
+
+const nationalBankOfPolandDataUpdateDateFormat = "2006-01-02 15:04"
+const nationalBankOfPolandDataUpdateDateTimezone = "Europe/Warsaw"
+
+// NationalBankOfPolandDataSource defines the structure of exchange rates data source of National Bank of Poland
+type NationalBankOfPolandDataSource struct {
+	ExchangeRatesDataSource
+}
+
+// NationalBankOfPolandExchangeRateData represents the whole data from National Bank of Poland
+type NationalBankOfPolandExchangeRateData struct {
+	XMLName          xml.Name                          `xml:"exchange_rates"`
+	Date             string                            `xml:"date,attr"`
+	AllExchangeRates []*NationalBankOfPolandExchangeRate `xml:"mid-rate"`
+}
+
+// NationalBankOfPolandExchangeRate represents the exchange rate data from National Bank of Poland
+type NationalBankOfPolandExchangeRate struct {
+	Currency string `xml:"code,attr"`
+	Units    string `xml:"units,attr"`
+	Rate     string `xml:",chardata"`
+}
+
+// ToLatestExchangeRateResponse returns a view-object according to original data from National Bank of Poland
+func (e *NationalBankOfPolandExchangeRateData) ToLatestExchangeRateResponse(c *core.Context) *models.LatestExchangeRateResponse {
+	if len(e.AllExchangeRates) < 1 {
+		log.ErrorfWithRequestId(c, "[national_bank_of_poland_datasource.ToLatestExchangeRateResponse] all exchange rates is empty")
+		return nil
+	}
+
+	exchangeRates := make(models.LatestExchangeRateSlice, 0, len(e.AllExchangeRates))
+
+	for i := 0; i < len(e.AllExchangeRates); i++ {
+		exchangeRate := e.AllExchangeRates[i]
+
+		if _, exists := validators.AllCurrencyNames[exchangeRate.Currency]; !exists {
+			continue
+		}
+
+		finalExchangeRate := exchangeRate.ToLatestExchangeRate(c)
+
+		if finalExchangeRate == nil {
+			continue
+		}
+
+		exchangeRates = append(exchangeRates, finalExchangeRate)
+	}
+
+	timezone, err := time.LoadLocation(nationalBankOfPolandDataUpdateDateTimezone)
+
+	if err != nil {
+		log.ErrorfWithRequestId(c, "[national_bank_of_poland_datasource.ToLatestExchangeRateResponse] failed to get timezone, timezone name is %s", nationalBankOfPolandDataUpdateDateTimezone)
+		return nil
+	}
+
+	updateDateTime := e.Date + " 12:15" // Table A of the average foreign currency exchange rates is published (updated) on the NBP website on business days, between 11:45 a.m. and 12:15 p.m.
+	updateTime, err := time.ParseInLocation(nationalBankOfPolandDataUpdateDateFormat, updateDateTime, timezone)
+
+	if err != nil {
+		log.ErrorfWithRequestId(c, "[national_bank_of_poland_datasource.ToLatestExchangeRateResponse] failed to parse update date, datetime is %s", updateDateTime)
+		return nil
+	}
+
+	latestExchangeRateResp := &models.LatestExchangeRateResponse{
+		DataSource:    nationalBankOfPolandDataSource,
+		ReferenceUrl:  nationalBankOfPolandExchangeRateReferenceUrl,
+		UpdateTime:    updateTime.Unix(),
+		BaseCurrency:  nationalBankOfPolandBaseCurrency,
+		ExchangeRates: exchangeRates,
+	}
+
+	return latestExchangeRateResp
+}
+
+// ToLatestExchangeRate returns a data pair according to original data from National Bank of Poland
+func (e *NationalBankOfPolandExchangeRate) ToLatestExchangeRate(c *core.Context) *models.LatestExchangeRate {
+	amount, err := utils.StringToInt64(e.Units)
+
+	if err != nil {
+		log.WarnfWithRequestId(c, "[national_bank_of_poland_datasource.ToLatestExchangeRate] failed to parse amount, currency is %s, amount is %s", e.Currency, e.Units)
+		return nil
+	}
+
+	rate, err := utils.StringToFloat64(e.Rate)
+
+	if err != nil {
+		log.WarnfWithRequestId(c, "[national_bank_of_poland_datasource.ToLatestExchangeRate] failed to parse rate, currency is %s, rate is %s", e.Currency, e.Rate)
+		return nil
+	}
+
+	if rate <= 0 {
+		log.WarnfWithRequestId(c, "[national_bank_of_poland_datasource.ToLatestExchangeRate] rate is invalid, currency is %s, rate is %s", e.Currency, e.Rate)
+		return nil
+	}
+
+	finalRate := float64(amount) / rate
+
+	if math.IsInf(finalRate, 0) {
+		return nil
+	}
+
+	return &models.LatestExchangeRate{
+		Currency: e.Currency,
+		Rate:     utils.Float64ToString(finalRate),
+	}
+}
+
+// GetRequestUrls returns the National Bank of Poland data source urls
+func (e *NationalBankOfPolandDataSource) GetRequestUrls() []string {
+	return []string{nationalBankOfPolandInconvertibleCurrencyExchangeRateUrl, nationalBankOfPolandDailyExchangeRateUrl}
+}
+
+// Parse returns the common response entity according to the National Bank of Poland data source raw response
+func (e *NationalBankOfPolandDataSource) Parse(c *core.Context, content []byte) (*models.LatestExchangeRateResponse, error) {
+	nationalBankOfPolandData := &NationalBankOfPolandExchangeRateData{}
+
+	xmlDecoder := xml.NewDecoder(bytes.NewReader(content))
+	xmlDecoder.CharsetReader = utils.IdentReader
+	err := xmlDecoder.Decode(&nationalBankOfPolandData)
+
+	if err != nil {
+		log.ErrorfWithRequestId(c, "[national_bank_of_poland_datasource.Parse] failed to parse xml data, content is %s, because %s", string(content), err.Error())
+		return nil, errs.ErrFailedToRequestRemoteApi
+	}
+
+	latestExchangeRateResponse := nationalBankOfPolandData.ToLatestExchangeRateResponse(c)
+
+	if latestExchangeRateResponse == nil {
+		log.ErrorfWithRequestId(c, "[national_bank_of_poland_datasource.Parse] failed to parse latest exchange rate data, content is %s", string(content))
+		return nil, errs.ErrFailedToRequestRemoteApi
+	}
+
+	return latestExchangeRateResponse, nil
+}

pkg/settings/setting.go

@@ -64,8 +64,9 @@ const (
 
 // Exchange rates data source types
 const (
-	EuroCentralBankDataSource string = "euro_central_bank"
-	CzechNationalBankDataSource string = "czech_national_bank"
+	EuroCentralBankDataSource      string = "euro_central_bank"
+	CzechNationalBankDataSource    string = "czech_national_bank"
+	NationalBankOfPolandDataSource string = "national_bank_of_poland"
 )
 
 const (
@@ -415,6 +416,8 @@ func loadExchangeRatesConfiguration(config *Config, configFile *ini.File, sectio
 		config.ExchangeRatesDataSource = EuroCentralBankDataSource
 	} else if getConfigItemStringValue(configFile, sectionName, "data_source") == CzechNationalBankDataSource {
 		config.ExchangeRatesDataSource = CzechNationalBankDataSource
+	} else if getConfigItemStringValue(configFile, sectionName, "data_source") == NationalBankOfPolandDataSource {
+		config.ExchangeRatesDataSource = NationalBankOfPolandDataSource
 	} else {
 		return errs.ErrInvalidExchangeRatesDataSource
 	}

pkg/utils/io.go

@@ -0,0 +1,8 @@
+package utils
+
+import "io"
+
+// IdentReader returns the original io reader
+func IdentReader(encoding string, input io.Reader) (io.Reader, error) {
+	return input, nil
+}