| Author |
Message
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| PGoodhart |
 Posted: Tue Sep 14, 2004 10:08 am Post subject: XML Parser (Not MRM) Accessing Elements |
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Master
Joined: 17 Jun 2004
Posts: 278
Location: Harrisburg PA
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Guys,
Is it possible to access the values of XML elements using the XML parser?
When I try to access something using something like:
SET RQSValue = InputBody.ABC.RQS;
on an xml message like <ABC><RQS>AValue</RQS></ABC>
I keep getting back in the trace that the element doesn't exist.
If I examine the tree using trace and FIELDNAME it looks like:
InputBody.XML
and 7 other elements with blank namespaces
Does this make any sense?
If I do the same thing with the MRM-XML parser it works fine...
Thanks!
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Patrick Goodhart
MQ Admin/Web Developer/Consultant
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| jefflowrey |
| Posted: Tue Sep 14, 2004 10:39 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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That should work.
Can we see your trace?
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| PGoodhart |
| Posted: Tue Sep 14, 2004 11:21 am Post subject: |
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Master
Joined: 17 Jun 2004
Posts: 278
Location: Harrisburg PA
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Apparently I oversimplified, because with the simple example I gave it worked.
The message I am attempting to read is a good deal more complicated.
The big difference seems to be that the root elements looks like:
<abc:def><rqs>AValue</rqs></abc:def>
And I have tried to go after it as
SET RQSValue = InputBody."abc:def".rqs;
and
SET RQSValue = InputBody.abc:def.rqs;
and
SET RQSValue = InputBody.*[>].rqs; (which is what I really want)
and
SET RQSValue = InputBody.abc.rqs;
and
SET RQSValue = InputBody.def.rqs;
And then I ran into the problems...
I am going to try to replicate it again and get a good trace.
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Patrick Goodhart
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| PGoodhart |
| Posted: Tue Sep 14, 2004 11:29 am Post subject: |
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Master
Joined: 17 Jun 2004
Posts: 278
Location: Harrisburg PA
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with "ABC:DEF" and SET RQSValue = InputBody."ABC:DEF".RQS; and message like:
<?xml version="1.0" encoding="UTF-8"?>
<ABC:DEF><RQS>AValue</RQS></ABC:DEF>
2004-09-14 15:25:21.003440 5914 UserTrace BIP2537I: Node 'ABC.ABCFlow.Co
mpute': Executing statement 'DECLARE RQSValue CHARACTER '';' at (ABC.ABCFlow_Com
pute.CopyEntireMessage, 2.3).
2004-09-14 15:25:21.003503 5914 UserTrace BIP2537I: Node 'ABC.ABCFlow.Co
mpute': Executing statement 'SET RQSValue = InputBody.ABC:DEF.RQS;' at (ABC.ABCF
low_Compute.CopyEntireMessage, 3.3).
2004-09-14 15:25:21.003534 5914 UserTrace BIP2538I: Node 'ABC.ABCFlow.Co
mpute': Evaluating expression 'InputBody.ABC:DEF.RQS' at (ABC.ABCFlow_Compute.Co
pyEntireMessage, 3.1 .
2004-09-14 15:25:21.003889 5914 UserTrace BIP2543E: Node 'ABC.ABCFlow.Co
mpute': (ABC.ABCFlow_Compute.CopyEntireMessage, 3.2 : Failed to navigate to pa
th element because it does not exist.
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| TonyD |
| Posted: Tue Sep 14, 2004 3:09 pm Post subject: |
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Knight
Joined: 15 May 2001
Posts: 540
Location: New Zealand
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There are several difficulties with the examples you have shown. 'ABC:' denotes a namesapace. You must use the XMLNS, or MRM, parsers for such messages. The ESQL reference should therefore be of the type (from one of your examples):
| Code: |
| SET RQSValue = InputBody.XMLNS.abc:def.rqs; |
Also, case is critical so the above should really be:
| Code: |
| SET RQSValue = InputBody.XMLNS.ABC:DEF.RQS; |
However, this would still be invalid. In addition, your message should have an 'xmlns' declaration for the root element (not shown in your example?):
| Code: |
<ABCMSG xmlns:ABC="http://abc.com/ABC-2004/09/0102"...
<DEF>
<RQS>AValue</RQS>
</DEF>
</ABCMSG>
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If your message is reconstructed as above, the SET statement would be:
| Code: |
| SET RQSValue = InputBody.XMLNS.ABC:ABCMSG.ABC:DEF.ABC:RQS; |
Alternatively, if you do not specify a namespace 'prefix' the message would be:
| Code: |
<ABCMSG xmlns="http://abc.com/ABC-2004/09/0102"...
<DEF>
<RQS>AValue</RQS>
</DEF>
</ABCMSG> |
: and the ESQL would not require 'ABC:' to be specified:
| Code: |
SET RQSValue = InputBody.XMLNS.ABCMSG.DEF.RQS;
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| jefflowrey |
| Posted: Tue Sep 14, 2004 3:48 pm Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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I think you mean "InputRoot.XMLNS", as "InputBody.XMLNS" would be "InputRoot.XMLNS.XMLNS" if the last child of the InputRoot was the XMLNS parser sub-tree.
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| TonyD |
| Posted: Wed Sep 15, 2004 3:35 am Post subject: |
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Knight
Joined: 15 May 2001
Posts: 540
Location: New Zealand
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| Of course... I should have looked more closely at the example! ...was distracted by the other errors. Apologies... |
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| PGoodhart |
| Posted: Wed Sep 15, 2004 5:58 am Post subject: |
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Master
Joined: 17 Jun 2004
Posts: 278
Location: Harrisburg PA
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Number 1. Yes I know case matters. I was trying to write an example that doesn't expose anything sensitive. And if you notice I did change the case on my second message so the examples do match.
Number 2. I can't use namespaces as the namespaces are on a remote server, and the broker is isolated from the internet. Any realistic suggestions?
Number 3. Got it working in the XML as ABC:DEF. So apparently it can work that way.
Bottom Line: The broker was sick and needed to have some bad (rouge) execution groups deleted from the database table BROKERAAEG. That and very careful definitions cleared up the problems.
New Question: However the *[1] and *[>] don't seem to work as expect in the XML parser.
If I have an XML message like:
<ABC:DEF><A><B>BValue</B></A><C>CValue</C></ABC:DEF>
and I want to get the value of the <B> element why can't I do the following?
DECLARE AValue AS CHARACTER;
SET AValue = InputBody.*[1].*[1];
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| TonyD |
| Posted: Wed Sep 15, 2004 2:52 pm Post subject: |
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Knight
Joined: 15 May 2001
Posts: 540
Location: New Zealand
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| Quote: |
| Number 2. I can't use namespaces as the namespaces are on a remote server, and the broker is isolated from the internet. Any realistic suggestions? |
I'm not sure what you mean by the above. If elements in an XML message have namespace prefixes the broker will successfully resolve them so long as there is a corresponding 'xmlns:prefix' declaration. No reference to a remote server is required. |
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| TonyD |
| Posted: Wed Sep 15, 2004 5:22 pm Post subject: |
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Knight
Joined: 15 May 2001
Posts: 540
Location: New Zealand
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Further to my earlier reply, I am not sure whether you plan to use namespaces or not.
However, this message:
| Code: |
<ABC:DEF xmlns:ABC="http://ABC-2004-09-16">
<ABC:A>
<ABC:B>BValue</ABC:B>
</ABC:A>
<ABC:C>CValue</ABC:C>
</ABC:DEF>
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:submitted to this ESQL:
| Code: |
DECLARE ABC NAMESPACE 'http://ABC-2004-09-16';
DECLARE AValue CHARACTER;
SET AValue = InputRoot.XMLNS.ABC:DEF.*[2].*[1];
SET OutputRoot.XML.Msg.AValue = AValue;
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:delivers this output:
| Code: |
<Msg>
<AValue>BValue</AValue>
</Msg>
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Alternatively, this message:
| Code: |
<DEF xmlns="http://ABC-2004-09-16">
<A>
<B>BValue</B>
</A>
<C>CValue</C>
</DEF>
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:passed to this ESQL:
| Code: |
DECLARE AValue CHARACTER;
DECLARE A INTEGER CARDINALITY(InputRoot.XMLNS."http://ABC-2004-09-16":DEF.*[]);
DECLARE B INTEGER CARDINALITY(InputRoot.XMLNS."http://ABC-2004-09-16":DEF.*[2].*[]);
SET AValue = InputRoot.XMLNS."http://ABC-2004-09-16":DEF.*[2].*[1];
SET OutputRoot.XML.Msg.AValue = AValue;
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:also produces this output:
| Code: |
<Msg>
<AValue>BValue</AValue>
</Msg>
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The 'xmlns' declaration is seen as a child of 'DEF' and therefore element 'A' is child # 2.
If namespaces are used, the broker requires all elements to be suitably qualified in the ESQL. |
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| PGoodhart |
| Posted: Thu Sep 16, 2004 3:57 am Post subject: |
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Master
Joined: 17 Jun 2004
Posts: 278
Location: Harrisburg PA
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Thanks Tony,
You showed me what I was doing wrong.
I wasn't working with the namespaces properly, and that was exactly what you showed me. Kudos!
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MQ Admin/Web Developer/Consultant
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