/*
* $Id: IdempotentSecureHashMessageFilter.java 22146 2011-06-08 07:40:29Z dirk.olmes $
* --------------------------------------------------------------------------------------
* Copyright (c) MuleSoft, Inc. All rights reserved. http://www.mulesoft.com
*
* The software in this package is published under the terms of the CPAL v1.0
* license, a copy of which has been included with this distribution in the
* LICENSE.txt file.
*/
package org.mule.routing;
import org.mule.api.MessagingException;
import org.mule.api.MuleEvent;
import org.mule.api.routing.RoutingException;
import org.mule.api.transformer.TransformerException;
import org.mule.transformer.simple.ByteArrayToHexString;
import org.mule.transformer.simple.SerializableToByteArray;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
/**
* <code>IdempotentSecureHashMessageFilter</code> ensures that only unique messages are
* received by a service. It does this by calculating the SHA-256 hash of the message
* itself. This provides a value with an infinitesimally small chance of a collision. This
* can be used to filter message duplicates. Please keep in mind that the hash is
* calculated over the entire byte array representing the message, so any leading or
* trailing spaces or extraneous bytes (like padding) can produce different hash values
* for the same semantic message content. Care should be taken to ensure that messages do
* not contain extraneous bytes. This class is useful when the message does not support
* unique identifiers.
*/
public class IdempotentSecureHashMessageFilter extends IdempotentMessageFilter
{
private String messageDigestAlgorithm = "SHA-256";
private final SerializableToByteArray objectToByteArray = new SerializableToByteArray();
private final ByteArrayToHexString byteArrayToHexString = new ByteArrayToHexString();
@Override
protected String getIdForEvent(MuleEvent event) throws MessagingException
{
try
{
Object payload = event.getMessage().getPayload();
byte[] bytes = (byte[]) objectToByteArray.transform(payload);
MessageDigest md = MessageDigest.getInstance(messageDigestAlgorithm);
byte[] digestedBytes = md.digest(bytes);
return (String)byteArrayToHexString.transform(digestedBytes);
}
catch (NoSuchAlgorithmException nsa)
{
throw new RoutingException(event,this, nsa);
}
catch (TransformerException te)
{
throw new RoutingException(event, this, te);
}
}
public String getMessageDigestAlgorithm()
{
return messageDigestAlgorithm;
}
public void setMessageDigestAlgorithm(String messageDigestAlgorithm)
{
this.messageDigestAlgorithm = messageDigestAlgorithm;
}
}