backend moved to separate directory

backend: deleted the old structure

go-backend/internal/utils/crypto.go

@@ -0,0 +1,101 @@
+package utils
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/base64"
+	"io"
+	"mime"
+	"mime/quotedprintable"
+	"net/mail"
+	"strings"
+)
+
+type Email struct {
+	MimeVersion string
+	Date        string
+	From        string
+	To          string
+	Subject     string
+	ContentType string
+	Body        string
+}
+
+func GenerateRandomString(length int) (string, error) {
+	bytes := make([]byte, length)
+	_, err := rand.Read(bytes)
+	if err != nil {
+		return "", err
+	}
+	return base64.URLEncoding.EncodeToString(bytes), nil
+}
+
+func GenerateVerificationToken() (string, error) {
+	return GenerateRandomString(32)
+}
+
+func DecodeMail(message string) (*Email, error) {
+	msg, err := mail.ReadMessage(strings.NewReader(message))
+	if err != nil {
+		return nil, err
+	}
+	decodedBody, err := io.ReadAll(msg.Body)
+	if err != nil {
+		return nil, err
+	}
+	decodedBodyString, err := DecodeQuotedPrintable(string(decodedBody))
+	if err != nil {
+		return nil, err
+	}
+	decodedSubject, err := DecodeRFC2047(msg.Header.Get("Subject"))
+	if err != nil {
+		return nil, err
+	}
+
+	email := &Email{}
+
+	// Populate the headers
+	email.MimeVersion = msg.Header.Get("Mime-Version")
+	email.Date = msg.Header.Get("Date")
+	email.From = msg.Header.Get("From")
+	email.To = msg.Header.Get("To")
+	email.Subject = decodedSubject
+	email.Body = decodedBodyString
+	email.ContentType = msg.Header.Get("Content-Type")
+
+	return email, nil
+}
+
+func DecodeRFC2047(encoded string) (string, error) {
+	decoder := new(mime.WordDecoder)
+	decoded, err := decoder.DecodeHeader(encoded)
+	if err != nil {
+		return "", err
+	}
+	return decoded, nil
+}
+
+func DecodeQuotedPrintable(encodedString string) (string, error) {
+	// Decode quoted-printable encoding
+	reader := quotedprintable.NewReader(strings.NewReader(encodedString))
+	decodedBytes := new(bytes.Buffer)
+	_, err := decodedBytes.ReadFrom(reader)
+	if err != nil {
+		return "", err
+	}
+	return decodedBytes.String(), nil
+}
+
+func EncodeQuotedPrintable(s string) string {
+	var buf bytes.Buffer
+
+	// Use Quoted-Printable encoder
+	qp := quotedprintable.NewWriter(&buf)
+
+	// Write the UTF-8 encoded string to the Quoted-Printable encoder
+	qp.Write([]byte(s))
+	qp.Close()
+
+	// Encode the result into a MIME header
+	return mime.QEncoding.Encode("UTF-8", buf.String())
+}