XMLExtract:Reading elements and attributes with same name 2

jfuentesve

• January 26, 2013 00:00

• Answered

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The question title is repeated cause it fits my case but it is indeed different.

I have a simple but complicated case, I am trying to fix a reader after an engine upgrade, and this has taking me a couple of days of frustration that I finally got here. This is what I'm trying to get:

I have this sample input file:

<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<feed xmlns:xs="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.w3.org/2005/Atom" xmlns:csm="http://www.blabla.org/feed/2.0">
  <entry>
    <id>urn:nid:24477</id>
    <csm:review star_rating="3">
      <csm:themes>
        <csm:theme id="1234">A theme value</csm:theme>
      </csm:themes>
    </csm:review>
    <summary><![CDATA[This is the summary of this review]]></summary>
  </entry>
</feed>

I found that the current faulty mapping code is this:

<Mappings>
    <Mapping element="entry" outPort="1" xmlFields="id" cloverFields="csm_id_uri">
        <Mapping element="csm:theme" outPort="0" parentKey="csm_id_uri" generatedKey="csm_id_uri" xmlFields="id" cloverFields="tag_id"/>
    </Mapping>
</Mappings>

This mapping just reads nothing, all the records the log says they go to port1, but when I dump it to a file, the records are empty, no data is passed.

I think (not sure yet, but...) the expected record should have:

|urn:nid:24477|||1234||

which is:

/feed/entry/id -> csm_id_uri = urn:nid:24477
/feed/entry/csm:review/csm:themes/csm:theme/@id -> tag_id = 1234

and the rest of the fields are left blank.


The point is that I can't get to have a single record with those values in a single record, I have been able to get one or the other, or two records per value.


I also tried this:

<Mapping element="entry" >

    <Mapping element="csm:review">
    <Mapping element="csm:themes">
        <Mapping element="csm:theme" outPort="1"
                 xmlFields="id;../../../id"
                 cloverFields="tag_id;csm_id_uri" />
    </Mapping>
    </Mapping>

</Mapping>

but no matter what combination I try, I can not refer to a child element using the dots, if the upper Id was an attribute instead of a child element, the problem would have been solved already. Is there a way to achieve this?


I'm looking for a general way to map N to 1 with this structure, for example, having the input

<feed>
  <entry>
    <id>5555<id>
    <listOfThings>
      <item id=33>item 1</item>
      <item id=44>item 2</item>
    </listOfThings>
  <entry>
  <entry>
    <id>6666<id>
    <listOfThings>
      <item id=77>item 3</item>
      <item id=88>item 4</item>
    </listOfThings>
  <entry>
<feed>

to get these records:

|5555|33|||
|5555|44|||
|6666|77|||
|6666|88|||

All the examples I have found are where the same name input fields are of the same nature, usually an attribute.

Can anyone please help?

Thank you in advance.

• 

  imriskal

  • January 29, 2013 10:29

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  Hi, jfuentesve,
  
  XMLExtract is not exactly the right component for this task. I would use XMLReader where it is possible control mapping with xpath expressions. The mapping would be as following:
  

  
  <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
  <Context xpath="//n2:theme" outPort="0" namespacePaths='n1="http://www.w3.org/2005/Atom";n2="http://www.blabla.org/feed/2.0"'>
  	<Mapping cloverField="field1" xpath="../../../n1:id"/>
  	<Mapping cloverField="field4" xpath="@id"/>
  </Context>
  

  
  This way you can process files with many entries or with many themes or both.
  
  Best regards,
• 

  jfuentesve

  • January 29, 2013 16:17

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  Comment actions Permalink

  Hi, thank you for your response.
  
  Unfortunately I can not find such a reader of type XMLReader available, these are the ones I can choose from:
  
  XMLExtract
  XMLXPathReader
  
  
  I went ahead and implemented a solution using XMLXpathReader, but now Im dealing with a missing class that should be accesible from the plugins:
  
  

  
  Error loading graph:/opt/ds/jetty-cloverServer/sandboxes/csm/graph/tag-association-program.grf Can't create object of type XML_XPATH_READER with reason: net/sf/saxon/sxpath/XPathEvaluator
  

  
  
  I can run it locally from Eclipse and it works with a java test, but doesn't work once deployed in the server, anyways that is not related to the topic. (though some help is welcome)
  
  
  This is what I'm using with XMLXpathReader:
  
  Tha mapping:
  
  

  
  <Context xpath="/feed/entry" outPort="0" sequenceField="IndexKey" namespacePaths='"http://www.w3.org/2005/Atom";csm="http://www.blahblah.org/feed/2.0"'>
     <Mapping xpath="./id" cloverField="csm_id_uri"/>
     <Context xpath="./csm:review/csm:themes/csm:theme" parentKey="IndexKey" generatedKey="ThemeIndexKey" outPort="1">
      <Mapping xpath="./@id" cloverField="tag_id"/>
     </Context>
  </Context>
  

  
  
  The node usage:
  
  Screen shot 2013-01-29 at 11.07.03 AM.png
  
  The corresponding edges have these fields:
  
  csm_id_uri;IndexKey
  tag_id;ThemeIndexKey
  
  I had to invert the order of the ports from/to the reader and the hash join to choose the right master key, using the keys in the mapping for the matching, it works like a charm.
  
  We are using clover 3.2.1. engine and designer.

  • Screen shot 2013-01-29 at 11.07.03 AM.png

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