org.hibernate.search.elasticsearch.aws.impl.AWSPayloadHashingRequestInterceptor.java Source code

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Here is the source code for org.hibernate.search.elasticsearch.aws.impl.AWSPayloadHashingRequestInterceptor.java

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/*
 * Hibernate Search, full-text search for your domain model
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.search.elasticsearch.aws.impl;

import java.io.IOException;
import java.io.OutputStream;
import java.security.DigestOutputStream;
import java.security.MessageDigest;

import org.apache.commons.codec.binary.Hex;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.http.HttpEntity;
import org.apache.http.HttpEntityEnclosingRequest;
import org.apache.http.HttpException;
import org.apache.http.HttpRequest;
import org.apache.http.HttpRequestInterceptor;
import org.apache.http.protocol.HttpContext;

import static org.apache.commons.codec.digest.DigestUtils.getSha256Digest;

/**
 * Interceptor computing the hash of the request payload.
 * <p>
 * Implemented separately from {@link AWSSigningRequestInterceptor} in order
 * to trigger content-length computation before the Apache HTTP client
 * generates the content-length header.
 *
 * @see <a href="https://hibernate.atlassian.net/browse/HSEARCH-2831">HSEARCH-2831</a>
 *
 * @author Yoann Rodiere
 */
class AWSPayloadHashingRequestInterceptor implements HttpRequestInterceptor {

    public static final String CONTEXT_ATTRIBUTE_HASH = AWSPayloadHashingRequestInterceptor.class.getName()
            + "_hash";

    private static final OutputStream DISCARDING_STREAM = new OutputStream() {
        @Override
        public void write(byte[] b, int off, int len) throws IOException {
        }

        @Override
        public void write(int b) throws IOException {
        }
    };

    @Override
    public void process(HttpRequest request, HttpContext context) throws HttpException, IOException {
        String contentHash = computeContentHash(request);
        context.setAttribute(CONTEXT_ATTRIBUTE_HASH, contentHash);
    }

    private String computeContentHash(HttpRequest request) throws IOException {
        HttpEntity entity = getEntity(request);
        if (entity == null) {
            return DigestUtils.sha256Hex("");
        }
        if (!entity.isRepeatable()) {
            throw new IllegalStateException("Cannot sign AWS requests with non-repeatable entities");
        }

        final MessageDigest digest = getSha256Digest();
        DigestOutputStream digestStream = new DigestOutputStream(DISCARDING_STREAM, digest);
        entity.writeTo(digestStream);
        return Hex.encodeHexString(digest.digest());
    }

    private HttpEntity getEntity(HttpRequest request) throws IOException {
        if (request instanceof HttpEntityEnclosingRequest) {
            return ((HttpEntityEnclosingRequest) request).getEntity();
        } else {
            return null;
        }
    }

}