From: Robert Klemme <shortcutter@...>
Date: 2013-06-16T23:35:17+09:00
Subject: Re: NokoGiri XML Parser

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On Fri, Jun 14, 2013 at 6:46 PM, Devender P. <lists@ruby-forum.com> wrote:

> The problem with xpath or maybe i am not sure how to use it but if i say
>
> doc.xpath("tlv componentInstances") produces the list of all attirbutes
> inside the componentInstances without giving me the hierarchy.
>
> Here is what i have in my XML.
>
> Each cellname with a type "HIER" will have <componentInstances> tag with
> additional attributes.
>
>
>   <CELLNAME>A1
>   <TYPE>HIER...
>   <COMPONENTINSTANCES>...
>       <CELLNAME>A2
>       <TYPE>HIER
>       <COMPONENTINSTANCES>
>         <CELLNAME>A3
>         <TYPE>MODEL....
>        </COMPONENTINSTANCES>
>       <CELLNAME>B2
>       <TYPE>MODEL
>    </COMPONENTINSTANCES>
>

This is not valid XML.  Where are the closing tags for <CELLNAME> and
<TYPE>?


> I want to be able to capture the componentInstances with respect to the
> parent cell.
>

You'll likely need a two step approach: search for all <CELLNAME> and for
each one of them search for the closest anchestor <CELLNAME>.

require 'nokogiri'

def c_name(c_node)
  t = c_node.at_xpath('n/text()') and t.to_s
end

dom = Nokogiri.XML <<XML_DOC
<root>
  <c>
    <n>foo</n>
    <c>
    <n>bar</n>
    <c>
      <n>bat</b>
    </c>
    </c>
  </c>
</root>
XML_DOC

dom.xpath('//c').each do |c_node|
  parent = c_node.at_xpath 'ancestor::c'

  if parent
    printf "Node: %s parent %s\n", c_name(c_node), c_name(parent)
  else
    printf "Node: %s no parent\n", c_name(c_node)
  end
end



> Please feel free to suggest a different XML structure if the paresers
> can handle them better.


I would start with _valid_ XML.  You should model the XML primarily
according to the requirements of the model that you need to created and not
necessarily according to what will have the easiest XPath for retrieval.

Cheers

robert


-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

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<div dir=3D"ltr"><br><div class=3D"gmail_extra"><br><br><div class=3D"gmail=
_quote">On Fri, Jun 14, 2013 at 6:46 PM, Devender P. <span dir=3D"ltr">&lt;=
<a href=3D"mailto:lists@ruby-forum.com" target=3D"_blank">lists@ruby-forum.=
com</a>&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-=
left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;p=
adding-left:1ex">The problem with xpath or maybe i am not sure how to use i=
t but if i say<br>

<br>
doc.xpath(&quot;tlv componentInstances&quot;) produces the list of all atti=
rbutes<br>
inside the componentInstances without giving me the hierarchy.<br>
<br>
Here is what i have in my XML.<br>
<br>
Each cellname with a type &quot;HIER&quot; will have &lt;componentInstances=
&gt; tag with<br>
additional attributes.<br>
<br>
<br>
=A0 &lt;CELLNAME&gt;A1<br>
=A0 &lt;TYPE&gt;HIER...<br>
=A0 &lt;COMPONENTINSTANCES&gt;...<br>
=A0 =A0 =A0 &lt;CELLNAME&gt;A2<br>
=A0 =A0 =A0 &lt;TYPE&gt;HIER<br>
=A0 =A0 =A0 &lt;COMPONENTINSTANCES&gt;<br>
=A0 =A0 =A0 =A0 &lt;CELLNAME&gt;A3<br>
=A0 =A0 =A0 =A0 &lt;TYPE&gt;MODEL....<br>
=A0 =A0 =A0 =A0&lt;/COMPONENTINSTANCES&gt;<br>
=A0 =A0 =A0 &lt;CELLNAME&gt;B2<br>
=A0 =A0 =A0 &lt;TYPE&gt;MODEL<br>
=A0 =A0&lt;/COMPONENTINSTANCES&gt;<br></blockquote><div><br></div><div styl=
e>This is not valid XML. =A0Where are the closing tags for &lt;CELLNAME&gt;=
 and &lt;TYPE&gt;?</div><div style>=A0</div><blockquote class=3D"gmail_quot=
e" style=3D"margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-colo=
r:rgb(204,204,204);border-left-style:solid;padding-left:1ex">

I want to be able to capture the componentInstances with respect to the<br>
parent cell.<br></blockquote><div><br></div><div style>You&#39;ll likely ne=
ed a two step approach: search for all &lt;CELLNAME&gt; and for each one of=
 them search for the closest anchestor &lt;CELLNAME&gt;.</div><div style>
<br></div><div style><div>require &#39;nokogiri&#39;</div><div><br></div><d=
iv>def c_name(c_node)</div><div>=A0 t =3D c_node.at_xpath(&#39;n/text()&#39=
;) and t.to_s</div><div>end</div><div><br></div><div>dom =3D Nokogiri.XML &=
lt;&lt;XML_DOC</div>
<div>&lt;root&gt;</div><div>=A0 &lt;c&gt;</div><div>=A0 =A0 &lt;n&gt;foo&lt=
;/n&gt;</div><div>=A0 =A0 &lt;c&gt;</div><div>=A0 =A0 <span class=3D"" styl=
e=3D"white-space:pre">	</span>&lt;n&gt;bar&lt;/n&gt;</div><div>=A0 =A0 <spa=
n class=3D"" style=3D"white-space:pre">	</span>&lt;c&gt;</div>
<div>=A0 =A0 <span class=3D"" style=3D"white-space:pre">	</span> =A0&lt;n&g=
t;bat&lt;/b&gt;</div><div>=A0 =A0 <span class=3D"" style=3D"white-space:pre=
">	</span>&lt;/c&gt;</div><div>=A0 =A0 &lt;/c&gt;</div><div>=A0 &lt;/c&gt;<=
/div><div>&lt;/root&gt;</div>
<div>XML_DOC</div><div><br></div><div>dom.xpath(&#39;//c&#39;).each do |c_n=
ode|</div><div>=A0 parent =3D c_node.at_xpath &#39;ancestor::c&#39;</div><d=
iv>=A0=A0</div><div>=A0 if parent</div><div>=A0 =A0 printf &quot;Node: %s p=
arent %s\n&quot;, c_name(c_node), c_name(parent)</div>
<div>=A0 else</div><div>=A0 =A0 printf &quot;Node: %s no parent\n&quot;, c_=
name(c_node)</div><div>=A0 end</div><div>end</div><div><br></div></div><div=
 style>=A0</div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0=
px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-le=
ft-style:solid;padding-left:1ex">
Please feel free to suggest a different XML structure if the paresers<br>
can handle them better.</blockquote></div><div class=3D"gmail_extra"><br></=
div>I would start with _valid_ XML. =A0You should model the XML primarily a=
ccording to the requirements of the model that you need to created and not =
necessarily according to what will have the easiest XPath for retrieval.</d=
iv>
<div class=3D"gmail_extra"><br></div><div class=3D"gmail_extra">Cheers</div=
><div class=3D"gmail_extra"><br></div><div class=3D"gmail_extra">robert<br>=
<br clear=3D"all"><div><br></div>-- <br>remember.guy do |as, often| as.you_=
can - without end<br>
<a href=3D"http://blog.rubybestpractices.com/">http://blog.rubybestpractice=
s.com/</a>
</div></div>

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