From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2011-04-11T16:37:41+09:00
Subject: Re: Can you search in REXML by attributes?

On Mon, Apr 11, 2011 at 1:27 AM, Kyle X. <haebooty@yahoo.com> wrote:
> Kyle X. wrote in post #992033:
>> "Jesús Gabriel y Galán" <jgabrielygalan@gmail.com> wrote in post
>> #990433:
>>>
>>> I usually use Nokogiri to handle XML documents, and find css selectors
>>> easier than XPath. I'd do it like this:
>>>
>>> doc = Nokogiri::XML(<<END
>>> <root xmlns:exp="http://foo" xmlns:xsi="http://bar">
>>> <IfcWallStandardCase id="i1677">
>>>  <ObjectPlacement>
>>>    <IfcLocalPlacement xsi:nil="true" ref="i1671"/>
>>>  </ObjectPlacement>
>>> </IfcWallStandardCase>
>>>
>>> <IfcAxis2Placement3D id="i1671">
>>>  <Location>
>>>    <IfcCartesianPoint xsi:nil="true" ref="i1667"/>
>>>  </Location>
>>> </IfcAxis2Placement3D>
>>>
>>> <IfcCartesianPoint id="i1667">
>>>  <Coordinates id="i1670" exp:cType="list">
>>>    <IfcLengthMeasure exp:pos="0">117.4</IfcLengthMeasure>
>>>    <IfcLengthMeasure exp:pos="1">119.7</IfcLengthMeasure>
>>>    <IfcLengthMeasure exp:pos="2">0.</IfcLengthMeasure>
>>>  </Coordinates>
>>> </IfcCartesianPoint>
>>> </root>
>>> END
>>> )
>>>
>>> reference = doc.css("#i1671 Location
>>> IfcCartesianPoint").attribute("ref").value
>>> doc.css("##{reference} Coordinates IfcLengthMeasure").map {|element|
>>> element.text}
>>>
>>> This returns: => ["117.4", "119.7", "0."]
>
> Please disregard the previous post.  I figured out how to load the
> files, but it does not appear to be reading correctly.
>
> Using-
> fname = File.open("C:/Users/Kyle/Desktop/CSUF/Research Winter
> 11/IFXCML/automation trials/one.xml")
> $doc = Nokogiri::XML(fname)
> reference = $doc.css(" IfcCartesianPoint Coordinates
> IfcLengthMeasure").first
>
> This produce and output of nil when it should be "117.4" correct?  What
> is going wrong here?
>

This works for me:

$ cat noko.rb && ruby -rubygems noko.rb
require 'nokogiri'

doc = Nokogiri::XML(File.read("one.xml"))
reference = doc.css("IfcCartesianPoint Coordinates IfcLengthMeasure").first
puts reference.text

117.4

But if I leave a space before IfcCartesianPoint in the call to the css
method I get a parser error  (`on_error': unexpected ' ' after ''
(Nokogiri::CSS::SyntaxError)). This is my file one.xml:

<root xmlns:exp="http://foo" xmlns:xsi="http://bar">
  <IfcWallStandardCase id="i1677">
       <ObjectPlacement>
         <IfcLocalPlacement xsi:nil="true" ref="i1671"/>
      </ObjectPlacement>
  </IfcWallStandardCase>

  <IfcAxis2Placement3D id="i1671">
     <Location>
       <IfcCartesianPoint xsi:nil="true" ref="i1667"/>
    </Location>
  </IfcAxis2Placement3D>

  <IfcCartesianPoint id="i1667">
     <Coordinates id="i1670" exp:cType="list">
         <IfcLengthMeasure exp:pos="0">117.4</IfcLengthMeasure>
         <IfcLengthMeasure exp:pos="1">119.7</IfcLengthMeasure>
         <IfcLengthMeasure exp:pos="2">0.</IfcLengthMeasure>
      </Coordinates>
  </IfcCartesianPoint>
</root>

This works too:

doc.css("IfcCartesianPoint Coordinates IfcLengthMeasure").each {|el|
puts el.text}

Produces:

117.4
119.7
0.

Maybe it's the way you are passing the file to Nokogiri::XML? By the
way, in your way you are not closing the file handler. If you want to
pass Nokogiri the file instead of reading it yourself you can do:

doc = nil
File.open("one.xml") {|f| doc = Nokogiri::XML(f)}

or

doc = File.open("one.xml") {|f| Nokogiri::XML(f)}

This way, the file is properly closed.

Jesus.