return null;
        }

        @Override
        @Nonnull
        public InputStream openStream() throws IOException {
            return new ByteArrayInputStream(xml.getBytes(StandardCharsets.UTF_8));
        }

        @Override
        @Nonnull
        public String getLocation() {
            return artifact.getId();
        }

        @Override
        @Nullable

     */
    private String getId(final String sessionId, final String url) {
        final String id = sessionId + ID_SEPARATOR + new String(Base64.getUrlEncoder().withoutPadding().encode(url.getBytes(UTF_8)), UTF_8);
        if (id.length() <= idPrefixLength) {
            return id;
        }
        return id.substring(0, idPrefixLength) + MessageDigestUtil.digest("SHA-256", id.substring(idPrefixLength));
    }

 * href="http://tools.ietf.org/html/rfc4648">RFC 4648</a>. For example, the expression:
 *
 * {@snippet :
 * BaseEncoding.base32().encode("foo".getBytes(US_ASCII))
 * }
 *
 * <p>returns the string {@code "MZXW6==="}, and
 *
 * {@snippet :
 * byte[] decoded = BaseEncoding.base32().decode("MZXW6===");
 * }
 *

                    // cache
                    putResultDataBody(dataMap, fessConfig.getIndexFieldCache(), new String(InputStreamUtil.getBytes(is), charSet));
                    putResultDataBody(dataMap, fessConfig.getIndexFieldHasCache(), Constants.TRUE);
                } catch (final Exception e) {

                    throw new SearchQueryException("Invalid facet field: " + f);
                }
                final String encodedField = BaseEncoding.base64().encode(f.getBytes(StandardCharsets.UTF_8));
                final TermsAggregationBuilder termsBuilder =
                        AggregationBuilders.terms(Constants.FACET_FIELD_PREFIX + encodedField).field(f);