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| pcelari |
 Posted: Wed Nov 04, 2009 5:40 am Post subject: how to remove empty nodes in XML? |
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Chevalier
Joined: 31 Mar 2006
Posts: 411
Location: New York
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Hi,
the service I called returns a XML tree that contains large number of empty fields.
Is there a simple way to remove all those empty fields?
thanks for any insight!
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pcelari
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- a master of always being a newbie |
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| mqjeff |
| Posted: Wed Nov 04, 2009 6:43 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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Yes.
Use the XMLNSC domain. |
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| pcelari |
| Posted: Wed Nov 04, 2009 7:22 am Post subject: |
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Chevalier
Joined: 31 Mar 2006
Posts: 411
Location: New York
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Sorry, I wasn't clear enough.
Yes, I'm already using XMLNSC.
There might be a better way of doing this than recursively removing empty fields in the tree.
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pcelari
-----------------------------------------
- a master of always being a newbie
Last edited by pcelari on Wed Nov 04, 2009 7:51 am; edited 1 time in total |
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| Vitor |
| Posted: Wed Nov 04, 2009 7:31 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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I'm not aware of a "remove empty fields" switch (but that's not to say there isn't one!) but a simple bit of ESQL (I agree recursive) should be able to do the trick.
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| mqjeff |
| Posted: Wed Nov 04, 2009 7:42 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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| What exactly do you mean by an empty field? |
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| pcelari |
| Posted: Wed Nov 04, 2009 7:50 am Post subject: |
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Chevalier
Joined: 31 Mar 2006
Posts: 411
Location: New York
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I mean nodes like:
<ThisTagContainsNothing/>
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pcelari
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| Vitor |
| Posted: Wed Nov 04, 2009 8:06 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| pcelari wrote: |
I mean nodes like:
<ThisTagContainsNothing/> |
I did think that's what you meant.
The issue here is that those tags are valid XML so no parser is going to strip them out. I still don't believe there's a switch in WMB to automatically remove them from the message tree, and if you don't want them (given that they possibly convey something) then it's a matter for your code.
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| mqjeff |
| Posted: Wed Nov 04, 2009 8:10 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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| I think that I'm going to await further comment from kimbert. |
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| Vitor |
| Posted: Wed Nov 04, 2009 8:23 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| mqjeff wrote: |
| I think that I'm going to await further comment from kimbert. |
Who's the person most likely to
a) have an informed opinion on this matter
b) know of the existence (or not) of a "remove empty fields" switch, possibly having developed it!!
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| kimbert |
| Posted: Wed Nov 04, 2009 11:30 am Post subject: |
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Jedi Council
Joined: 29 Jul 2003
Posts: 5543
Location: Southampton
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The XMLNSC parser will remove non-significant white space, comments and processing instructions if you want it to. However, there is no switch ( and none planned ) to remove empty tags. Those are genuinely a part of the data, as Vitor correctly pointed out above.
I suggests a recursive walk of the message tree, removing the tags that you don't want. Or an ESQL function which you call when mapping each tag, to detect the empty ones and *not* map those. |
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| pcelari |
| Posted: Wed Nov 04, 2009 12:28 pm Post subject: |
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Chevalier
Joined: 31 Mar 2006
Posts: 411
Location: New York
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thanks for all the insights, here's the code modified from the original StripNamespaces. I've yet to test it, though.
CREATE PROCEDURE RemoveNullNodes(IN StartRefPtr REFERENCE)
BEGIN
DECLARE FieldRefPtr REFERENCE TO StartRefPtr;
MOVE FieldRefPtr FIRSTCHILD;
IF LASTMOVE(FieldRefPtr) THEN
IF FieldRefPtr = NULL THEN
delete field FieldRefPtr;
END IF;
END IF;
WHILE LASTMOVE(FieldRefPtr) DO
CALL RemoveNullNodes(FieldRefPtr);
IF FieldRefPtr = NULL THEN
delete field FieldRefPtr;
END IF;
MOVE FieldRefPtr NEXTSIBLING;
END WHILE;
END;
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pcelari
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| Gemz |
| Posted: Wed Nov 04, 2009 10:15 pm Post subject: |
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Centurion
Joined: 14 Jan 2008
Posts: 124
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Hi,
You can try passing this message through mapping node. I guess it will remove those empty tags.(Though this is not the actual purpose of mapping node.
-GemZ
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"An expert is one who knows more and more about less and less until he knows absolutely everything about nothing...." |
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| goffinf |
| Posted: Sat Nov 14, 2009 5:20 pm Post subject: |
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Chevalier
Joined: 05 Nov 2005
Posts: 401
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You can do it as a simple XSLT transform :-
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:fo="http://www.w3.org/1999/XSL/Format">
<xsl:template match="*">
<xsl:copy>
<xsl:copy-of select="@*"/>
<xsl:apply-templates/>
</xsl:copy>
</xsl:template>
<xsl:template match="*[not(node())]"/>
</xsl:stylesheet> |
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