Nsryjdtyk

The transaction start monitoring event of an IIB flow with a MQ Input node produces a base64 encoded byte array of the MQ message. Now I would like to write a Java program that reconstructs this byte array so I can read the headers and body.

The base64 MQ messages looks like this:

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

I made following tests to parse this in Java:

import java.io.ByteArrayInputStream;

import java.io.DataInputStream;

import javax.xml.bind.DatatypeConverter;

import org.apache.commons.io.IOUtils;

import org.junit.Assert;

import org.junit.Test;

import com.ibm.mq.headers.CCSID;

import com.ibm.mq.headers.MQHeaderList;

import com.ibm.mq.headers.MQMD;

import com.ibm.mq.headers.MQRFH2;



public class MqMsgTest {



    @Test

    public void allGood() throws Exception {

        String msgBase64 = IOUtils.toString(getClass().getResourceAsStream("/mq-msg.base64"), "UTF-8");

        byte msgBytes = DatatypeConverter.parseBase64Binary(msgBase64);

        DataInputStream msgStream = new DataInputStream(new ByteArrayInputStream(msgBytes));

        MQMD mqmd = new MQMD(msgStream);

        Assert.assertEquals("MQHRF2  ", mqmd.getFormat());

        Assert.assertEquals("daniel      ", mqmd.getUserIdentifier());

        MQRFH2 mqrfh2 = new MQRFH2(msgStream);

        Assert.assertEquals("TheValue", mqrfh2.getStringFieldValue("usr", "TheKey"));

        String body = IOUtils.toString(msgStream, CCSID.getCodepage(mqrfh2.nextCharacterSet()));

        Assert.assertEquals("<foo>bar</foo>", body);

    }



    @Test

    public void doesNotWork() throws Exception {

        String msgBase64 = IOUtils.toString(getClass().getResourceAsStream("/mq-msg.base64"), "UTF-8");

        byte msgBytes = DatatypeConverter.parseBase64Binary(msgBase64);

        DataInputStream msgStream = new DataInputStream(new ByteArrayInputStream(msgBytes));

        MQHeaderList headers = new MQHeaderList(msgStream, true);

        Assert.assertEquals(2, headers.size());

    }

}

The allGood() test parses the headers and body nicely. But it would fail if the message would not contain a RFH2 header. The doesNotWork() test should parse the headers in a generic way, but it does not work.

How can I parse the base64 encoded MQ message in a flexible way so I have access to the headers and the body?

The transaction start monitoring event of an IIB flow with a MQ Input
node produces a base64 encoded byte array of the MQ message. Now I
would like to write a Java program that reconstructs this byte array
so I can read the headers and body.

Why? Why do you combine the MQMD and the MQRFH2 structures then encode it with Base64 only to want to extract it with a Java program?

It sounds like a very poor design.

I dropped your Base64 message into a program that outputs a hex dump of it:

000000: 4D442020 02000000 00000000 08000000  MD  ............

000010: FFFFFFFF 00000000 11010000 B8040000  ????........?...

000020: 4D514852 46322020 04000000 01000000  MQHRF2  ........

000030: 414D5120 43454D42 52412020 20202020  AMQ CEMBRA      

000040: A555F85B 25C7B602 00000000 00000000  ?U?[%??.........

000050: 00000000 00000000 00000000 00000000  ................

000060: 00000000 20202020 20202020 20202020  ....            

000070: 20202020 20202020 20202020 20202020                  

000080: 20202020 20202020 20202020 20202020                  

000090: 20202020 43454D42 52412020 20202020      CEMBRA      

0000a0: 20202020 20202020 20202020 20202020                  

0000b0: 20202020 20202020 20202020 20202020                  

0000c0: 20202020 64616E69 656C2020 20202020      daniel      

0000d0: 16010515 000000E2 6E8175FB 01D228EA  .......?n?u?.?(?

0000e0: 4D51FDE9 03000000 00000000 0000000B  MQ??............

0000f0: 20202020 20202020 20202020 20202020                  

000100: 20202020 20202020 20202020 20202020                  

000110: 0B000000 302E395C 636F6D6D 6F6E5C6A  ....0.9commonj

000120: 646B5C62 696E5C6A 61766177 2E657865  dkbinjavaw.exe

000130: 32303138 31313235 31343336 31323437  2018112514361247

000140: 20202020 00000000 00000000 00000000      ............

000150: 00000000 00000000 00000000 01000000  ................

000160: 00000000 00000000 FFFFFFFF 52464820  ........????RFH 

000170: 00000002 000000BC 00000111 000004B8  .......?.......?

000180: 4D515354 52202020 00000000 000004B8  MQSTR   .......?

000190: 00000020 3C6D6364 3E3C4D73 643E6A6D  ... <mcd><Msd>jm

0001a0: 735F7465 78743C2F 4D73643E 3C2F6D63  s_text</Msd></mc

0001b0: 643E2020 00000048 3C6A6D73 3E3C4473  d>  ...H<jms><Ds

0001c0: 743E7175 6575653A 2F2F2F4D 4F4E493C  t>queue:///MONI<

0001d0: 2F447374 3E3C546D 733E3135 34333135  /Dst><Tms>154315

0001e0: 36353732 3435363C 2F546D73 3E3C446C  6572456</Tms><Dl

0001f0: 763E323C 2F446C76 3E3C2F6A 6D733E20  v>2</Dlv></jms> 

000200: 00000024 3C757372 3E3C5468 654B6579  ...$<usr><TheKey

000210: 3E546865 56616C75 653C2F54 68654B65  >TheValue</TheKe

000220: 793E3C2F 7573723E 3C666F6F 3E626172  y></usr><foo>bar

000230: 3C2F666F 6F3E                        </foo>          

The decoded message starts off with the MQMD which is 364 bytes then the MQRFH2 structures which is 202 bytes.

The MQHeaderList class is extremely picky about parsing an MQMessage. The message MUST begin with one of the known MQ classes or it will throw an exception. Using MQHeaderList class for problem messages will probably just lead to more problems.

It would be better to simply dump the message in hex like I did then let the support person or developer figure out what the issue is.

MQHeaderList class is not a magic wand, although, I wish IBM would actually expand its use to include EVERY MQ header. Your problem is that you are assuming MQHeaderList class can do more than what it can. MQHeaderList class can only handle 11 internal MQ headers/structures (aka classes). See here: https://www.ibm.com/support/knowledgecenter/en/SSFKSJ_9.1.0/com.ibm.mq.dev.doc/q030880_.htm

i.e. MQRFH, MQRFH2, MQCIH, MQDLH, MQIIH, MQRMH, MQSAPH, MQWIH, MQXQH, MQDH & MQEPH

As you can see, MQMD is NOT on the list. So, your decoded Base64 message will NOT work with MQHeaderList class.

Also, you should read my comments about MQRFH2 being an embedded message here: Issue While Setting MQRFH2 header in IBM MQ

You have to plug and chug through the data stream that IIB created. Here's some basic code to do the job:

import java.io.ByteArrayInputStream;

import java.io.DataInputStream;

import javax.xml.bind.DatatypeConverter;

import com.ibm.mq.headers.MQMD;

import com.ibm.mq.headers.MQRFH2;



public class Test_IIB_Data

{

   public static void main(String args)

   {

      String msgBase64 = "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";



      try

      {

         byte msgBytes = DatatypeConverter.parseBase64Binary(msgBase64);

         DataInputStream msgStream = new DataInputStream(new ByteArrayInputStream(msgBytes));



         MQMD md = new MQMD(msgStream);



         System.out.println("md.getFormat="+md.getFormat());

         System.out.println("md.getPutApplName="+md.getPutApplName());

         System.out.println("md.getUserIdentifier="+md.getUserIdentifier());



         MQRFH2 rfh2 = new MQRFH2(msgStream);



         System.out.println("rfh2.getFormat="+rfh2.getFormat());

         System.out.println("rfh2.usr.TheKey="+rfh2.getStringFieldValue("usr", "TheKey"));



         int bodyLen = msgBytes.length - rfh2.getStrucLength() - md.size();

         byte body = new byte[bodyLen];

         msgStream.read(body);

         System.out.println("body="+new String(body));

      }

      catch (Exception e)

      {

         e.printStackTrace();

      }

   }

}

And when you run it, the output should be:

md.getFormat=MQHRF2  

md.getPutApplName=0.9commonjdkbinjavaw.exe

md.getUserIdentifier=daniel      

rfh2.getFormat=MQSTR   

rfh2.usr.TheKey=TheValue

body=<foo>bar</foo>