refactor: new static TlsUtility::certFingerprint to generate fingerprint on the fly

src/lib/gui/tls/TlsUtility.cpp

@@ -70,6 +70,27 @@ int TlsUtility::getCertKeyLength(const QString &certPath)
   return deskflow::getCertLength(certPath.toStdString());
 }
 
+QByteArray TlsUtility::certFingerprint(const QString &certPath)
+{
+  QByteArray fingerprint;
+
+  const auto certs = QSslCertificate::fromPath(certPath);
+  if (certs.isEmpty()) {
+    //: %1 will be replaced by the certificate path
+    qDebug() << tr("failed to read key from certificate file: %1").arg(certPath);
+    return fingerprint;
+  }
+
+  const auto cert = certs.first();
+  if (cert.isNull()) {
+    //: %1 will be replaced by the certificate path
+    qWarning() << tr("failed to parse certificate file: %1").arg(certPath);
+    return fingerprint;
+  }
+
+  return cert.digest(QCryptographicHash::Sha256);
+}
+
 bool TlsUtility::generateCertificate() const
 {
   qDebug(

src/lib/gui/tls/TlsUtility.h

@@ -43,6 +43,14 @@ public:
    */
   static int getCertKeyLength(const QString &certPath = Settings::value(Settings::Security::Certificate).toString());
 
+  /**
+   * @brief get the SHA256 fingerprint of a certificatefile.
+   * @param certPath path of the file to fingerprint, when not set uses the vaule of Settings::Security::Certificate
+   * @return A QByteArray of the SHA256 fingerprint of the file or empty array if invalid file is passed
+   */
+  // clang-format off
+  static QByteArray certFingerprint(const QString &certPath = Settings::value(Settings::Security::Certificate).toString());
+  // clang-format on
 private:
   TlsCertificate m_certificate;
 };