chore: extract.PEM replaces PEM parse functions

internal/openvpn/extract/pem.go

@@ -0,0 +1,33 @@
+package extract
+
+import (
+	"encoding/pem"
+	"errors"
+	"regexp"
+	"strings"
+)
+
+var (
+	errPEMDecode = errors.New("cannot decode PEM encoded block")
+)
+
+var (
+	regexPEMBegin = regexp.MustCompile(`-----BEGIN [A-Za-z ]+-----`)
+	regexPEMEnd   = regexp.MustCompile(`-----END [A-Za-z ]+-----`)
+)
+
+func PEM(b []byte) (encodedData string, err error) {
+	pemBlock, _ := pem.Decode(b)
+	if pemBlock == nil {
+		return "", errPEMDecode
+	}
+
+	encodedBytes := pem.EncodeToMemory(pemBlock)
+	encodedData = string(encodedBytes)
+	encodedData = strings.ReplaceAll(encodedData, "\n", "")
+	beginPrefix := regexPEMBegin.FindString(encodedData)
+	encodedData = strings.TrimPrefix(encodedData, beginPrefix)
+	endPrefix := regexPEMEnd.FindString(encodedData)
+	encodedData = strings.TrimSuffix(encodedData, endPrefix)
+	return encodedData, nil
+}