Mule Zip File and send zipped file towards FTP server

Question

I know Mule has great support for gzip compression of data using the element. However the client now wants zip compression since the file has to be placed on an FTP as a zip co

Answer 1

In the ZipTransformer constructor, the following is deprecated.

registerSourceType(InputStream.class);
registerSourceType(byte[].class);

Use this instead:

registerSourceType(DataTypeFactory.create(InputStream.class));
registerSourceType(DataTypeFactory.create(byte[].class));

Answer 2

A simpler way to do it is to use the gzip transformer in mule to compress the file. Note that you have to do it through the xml.

<gzip-compress-transformer/>

Answer 3

I have implemented the transformer for this

    package com.test.transformer;

import java.io.IOException;
import java.io.InputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

import org.apache.commons.io.IOUtils;
import org.apache.commons.io.output.ByteArrayOutputStream;
import org.mule.api.MuleMessage;
import org.mule.api.transformer.TransformerException;
import org.mule.transformer.AbstractMessageTransformer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ZipTransformer
  extends AbstractMessageTransformer
{
  private static final Logger log = LoggerFactory.getLogger(ZipTransformer.class);
  public static final int DEFAULT_BUFFER_SIZE = 32768;
  public static byte[] MAGIC = { 'P', 'K', 0x3, 0x4 };

  public ZipTransformer()
  {
    registerSourceType(InputStream.class);
    registerSourceType(byte[].class);
  }

  public Object transformMessage(MuleMessage message, String outputEncoding)
    throws TransformerException
  {
    Object payload = message.getPayload();
    try{
        byte[] data;
        if (payload instanceof byte[])
        {
            data = (byte[]) payload;
        }
        else if (payload instanceof InputStream) {
            data = IOUtils.toByteArray((InputStream)payload);
        } 
        else if (payload instanceof String)
        {
            data = ((String) payload).getBytes(outputEncoding);
        }
        else
        {
            data = muleContext.getObjectSerializer().serialize(payload);
        }
        return compressByteArray(data);
    }catch (Exception ioex)
    {
        throw new TransformerException(this, ioex);
    }
  }

  public Object compressByteArray(byte[] bytes) throws IOException
  {
      if (bytes == null || isCompressed(bytes))
      {
          if (logger.isDebugEnabled())
          {
              logger.debug("Data already compressed; doing nothing");
          }
          return bytes;
      }

      if (logger.isDebugEnabled())
      {
          logger.debug("Compressing message of size: " + bytes.length);
      }

      ByteArrayOutputStream baos = null;
      ZipOutputStream  zos = null;

      try
      {
          baos = new ByteArrayOutputStream(DEFAULT_BUFFER_SIZE);
          zos = new ZipOutputStream(baos);
          zos.putNextEntry(new ZipEntry("test.txt"));
          zos.write(bytes, 0, bytes.length);
          zos.finish();
          zos.close();

          byte[] compressedByteArray = baos.toByteArray();

          baos.close();
          if (logger.isDebugEnabled())
          {
              logger.debug("Compressed message to size: " + compressedByteArray.length);
          }

          return compressedByteArray;
      }
      catch (IOException ioex)
      {
          throw ioex;
      }
      finally
      {
          IOUtils.closeQuietly(zos);
          IOUtils.closeQuietly(baos);
      }
  }

  public boolean isCompressed(byte[] bytes) throws IOException
  {
      if ((bytes == null) || (bytes.length < 4 ))
      {
          return false;
      }
      else
      {
          for (int i = 0; i < MAGIC.length; i++) {
                if (bytes[i] != MAGIC[i]) {
                 return false;
                }
          }
          return true;
      }
  }


}

Used it as

<custom-transformer class="com.test.transformer.ZipTransformer" doc:name="file zip transformer"/>

As of now sets file name as test.txt. you can change is using any property or variable.

Hope this helps.