@Override
  public InputStream readFrom(String spec, String requestMethod, String body, Map<String, String> headers)
      throws IOException {
    return getInputStream(spec, requestMethod, headers, body == null ? null : body.getBytes());
  }
Get an instance of HostPortRestrictionHandler

@return
ambari-server/src/main/java/org/apache/ambari/server/view/ViewURLStreamProvider.java