Squashed commit of the following:

commit 5b11756af6 Author: netscrawler <mariarthyjamesoo@gmail.com> Date: Thu Jul 4 00:44:15 2024 +0300 v0.1 commit c99f477e35 Author: netscrawler <mariarthyjamesoo@gmail.com> Date: Sun Jun 30 20:44:53 2024 +0300 v0.0.6
2026-09-05 08:29:36 +00:00 · 2024-07-04 00:45:11 +03:00
parent 61d2be39f1
commit 3085eb993a
19 changed files with 799 additions and 0 deletions
@@ -0,0 +1,177 @@
+package rateExtract
+
+import (
+	"compress/gzip"
+	"converter/internal/domain/models"
+	"encoding/xml"
+	"fmt"
+	"io"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	"golang.org/x/text/encoding/charmap"
+)
+
+type resultType struct {
+	XMLName xml.Name `xml:"ValCurs"`
+	Valute  []struct {
+		NumCode  string `xml:"NumCode"`
+		CharCode string `xml:"CharCode"`
+		Nominal  string `xml:"Nominal"`
+		Name     string `xml:"Name"`
+		Value    string `xml:"Value"`
+	} `xml:"Valute"`
+}
+
+type cacheKeyType struct {
+	CurrencyId string
+	Date       string
+}
+
+type cacheResultType struct {
+	Rate float64
+}
+
+var urlTemplate string = "https://www.cbr.ru/scripts/XML_daily.asp?date_req=%s"
+
+var cache map[cacheKeyType]*cacheResultType
+
+func GetExchangeRate(currencyId string) (models.VunitRate, error) {
+	date := time.Now()
+	if cache == nil {
+		cache = map[cacheKeyType]*cacheResultType{}
+	}
+
+	reqDate := fmt.Sprintf("%02d/%02d/%d", date.Day(), date.Month(), date.Year())
+
+	cacheKey := cacheKeyType{CurrencyId: currencyId, Date: reqDate}
+
+	cacheResult, exists := cache[cacheKey]
+
+	if !exists {
+
+		url := fmt.Sprintf(urlTemplate, reqDate)
+
+		req, err := http.NewRequest(http.MethodGet, url, nil)
+		if err != nil {
+			return models.VunitRate{}, err
+		}
+
+		req.Header.Add("accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7")
+		req.Header.Add("accept-encoding", "gzip, deflate, br")
+		req.Header.Add("accept-language", "en-US,en;q=0.9,ru;q=0.8")
+		req.Header.Add("cache-control", "max-age=0")
+		req.Header.Add("user-agent", "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/111.0.0.0 Safari/537.36")
+
+		client := &http.Client{}
+
+		resp, err := client.Do(req)
+		if err != nil {
+			return models.VunitRate{Currency: currencyId, Rate: 0}, err
+		}
+
+		defer resp.Body.Close()
+
+		var reader io.ReadCloser
+
+		switch resp.Header.Get("Content-Encoding") {
+		case "gzip":
+			reader, err = gzip.NewReader(resp.Body)
+			if err != nil {
+				return models.VunitRate{Currency: currencyId, Rate: 0}, err
+			}
+			defer reader.Close()
+		default:
+			reader = resp.Body
+		}
+
+		xml := xml.NewDecoder(reader)
+
+		xml.CharsetReader = func(charset string, input io.Reader) (io.Reader, error) {
+			switch charset {
+			case "windows-1251":
+				return charmap.Windows1251.NewDecoder().Reader(input), nil
+			default:
+				return nil, fmt.Errorf("unknown charset: %s", charset)
+			}
+		}
+
+		result := &resultType{}
+
+		err = xml.Decode(result)
+		if err != nil {
+			return models.VunitRate{Currency: currencyId, Rate: 0}, err
+		}
+
+		for _, resultRow := range result.Valute {
+
+			if resultRow.CharCode != currencyId {
+				continue
+			}
+
+			resultRow.Value = strings.Replace(resultRow.Value, ",", ".", 1)
+
+			rate, err := strconv.ParseFloat(resultRow.Value, 64)
+			if err != nil {
+				return models.VunitRate{Currency: currencyId, Rate: 0}, err
+			}
+
+			nominal, err := strconv.ParseInt(resultRow.Nominal, 10, 64)
+			if err != nil {
+				return models.VunitRate{Currency: currencyId, Rate: 0}, err
+			}
+
+			cacheResult = &cacheResultType{Rate: rate / float64(nominal)}
+
+			cache[cacheKey] = cacheResult
+
+		}
+
+	}
+	return models.VunitRate{Currency: currencyId, Rate: float32(cacheResult.Rate)}, nil
+
+}
+
+//func Convert(from string, to string, value float64, date time.Time) (float64, error) {
+//
+//	if from == to {
+//		return value, nil
+//	}
+//
+//	if value == 0 {
+//		return 0, nil
+//	}
+//
+//	result := value
+//
+//	if from != CurrencyRUB {
+//
+//		exchangeRate, err := GetExchangeRate(from, date)
+//		if err != nil {
+//			return 0, err
+//		}
+//
+//		result = result * exchangeRate
+//
+//	}
+//
+//	if to != CurrencyRUB {
+//
+//		exchangeRate, err := GetExchangeRate(to, date)
+//		if err != nil {
+//			return 0, err
+//		}
+//
+//		result = result / exchangeRate
+//
+//	}
+//
+//	return (math.Floor(result*100) / 100), nil
+//
+//}
+//
+//func main() {
+//	fmt.Println(GetExchangeRate(CurrencyUSD, time.Now()))
+//}