001/*
002 * (C) Copyright 2006-2019 Nuxeo (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     Florent Guillaume
018 */
019package org.nuxeo.ecm.core.blob;
020
021import java.util.Locale;
022import java.util.Map;
023import java.util.regex.Pattern;
024
025import org.apache.commons.codec.digest.DigestUtils;
026
027/**
028 * Configuration for the digest.
029 *
030 * @since 11.1
031 */
032public class DigestConfiguration extends PropertyBasedConfiguration {
033
034    public static final String DIGEST_ALGORITHM_PROPERTY = "digest";
035
036    public static final String DEFAULT_DIGEST_ALGORITHM = "MD5";
037
038    public final String digestAlgorithm;
039
040    public final Pattern digestPattern;
041
042    public DigestConfiguration(String digestAlgorithm) {
043        super(null, null);
044        this.digestAlgorithm = digestAlgorithm;
045        digestPattern = getDigestPattern();
046    }
047
048    public DigestConfiguration(String systemPropertyPrefix, Map<String, String> properties) {
049        super(systemPropertyPrefix, properties);
050        digestAlgorithm = getDigestAlgorithm();
051        digestPattern = getDigestPattern();
052    }
053
054    protected String getDigestAlgorithm() {
055        return getProperty(DIGEST_ALGORITHM_PROPERTY, DEFAULT_DIGEST_ALGORITHM).toUpperCase(Locale.ENGLISH);
056    }
057
058    protected Pattern getDigestPattern() {
059        // compute a dummy digest (from 0-length input) to know its length and derive a regexp
060        int len = new DigestUtils(digestAlgorithm).digestAsHex(new byte[0]).length();
061        return Pattern.compile("[0-9a-f]{" + len + "}");
062    }
063
064    public boolean isValidDigest(String digest) {
065        return digestPattern.matcher(digest).matches();
066    }
067
068}