From: Robert Klemme <shortcutter@...>
Date: 2009-12-01T03:45:08+09:00
Subject: Re: Odd puts behaviour with REXML

On 30.11.2009 19:33, John W Higgins wrote:
> [Note:  parts of this message were removed to make it a legal post.]
> 
> Morning David,
> 
> On Mon, Nov 30, 2009 at 10:19 AM, David Sainte-claire <
> dsainteclaire@gmail.com> wrote:
> 
>> Hello,
>>
>> This is really weird, and I'm not sure if maybe there's a formatting
>> option that I can set on the puts method that will solve it.  Hopefully
>> someone has done something similar??
>>
>> I have been using REXML to parse through an XML document that I get back
>> from calling a ReST-ish web service, and up until now it has parsed
>> every single element as I'd expect.  But I run into this small patch of
>> data were it acts weird.  The XML looks like this:
>>
>> <profile>
>> <support>
>> <title>eSupport</title>
>> <prefix>Find related product support and help in</prefix>
>> <link>
>>
>> http://www.somecompany.com/US/perl/model-home.pl?XID=M:products:crmportal&LOC=3&mdl=someModel
>> </link>
>> </support>
>> </profile>
>>
>> And I'm parsing it like this:
>> data.elements.each("product/profile/support"){|element|
>>  element.elements.each() do |child|
>>    puts "Did XPATH match any profile elements?"
>>    puts  child.text
>>  end
>> }
>>
>> I know it's pretty rudimentary, but I'm just confused as to why this
>> same pattern has been able to get text out of every other element I have
>> searched for, but here I get something like this when I loop through the
>> subelemenents:
>> Did XPATH match any profile elements?
>> ???Product_Support_Link_Title???
>> Did XPATH match any profile elements?
>> ???Product_Support_Link_Prefix???
>> Did XPATH match any profile elements?
>> ???Product_Support_Link???&mdl=someModel
>>
>> It looks like XPATH doesn't like the format of the text somehow, but I
>> have no idea what it is about it that it doesn't like since it appears
>> to be just normal text to me.
>>
>> Anyone have any ideas?  It looks like something that REXML is doing
>> since it outputs the path to the element in the document Product -->
>> Support but I don't have a clue where the _Link is coming from?
>>
>>
> Rule one of anything like this is to remove each element from the XML file
> one by one and see which one is breaking you. In this case you will find
> that it's the link element because you are using ampersands in the URL. See
> here
> 
> http://www.w3.org/TR/xhtml1/guidelines.html#C_12

One more hint: when posting things like this it is best to provide a 
_complete_ example.  From the XPath given it is clear that something 
must be missing (there are no "product" tags).  It's pretty easy with REXML:

robert@fussel ~
$ cat x.rb

require 'rexml/document'

data = REXML::Document.new <<'DOC'
<product>
<profile>
<support>
<title>eSupport</title>
<prefix>Find related product support and help in</prefix>
<link>
http://www.somecompany.com/US/perl/model-home.pl?XID=M:products:crmportal&LOC=3&mdl=someModel
</link>
</support>
</profile>
</product>
DOC


data.elements.each("product/profile/support"){|element|
   element.elements.each() do |child|
     puts "Did XPATH match any profile elements?"
     puts  child.text
   end
}

Which on my box produces:

robert@fussel ~
$ ruby19 x.rb
/usr/local/lib/ruby19/1.9.1/rexml/parsers/treeparser.rb:95:in `rescue in 
parse': #<RuntimeError: Illegal character '&' in raw string " 
(REXML::ParseException)
http://www.somecompany.com/US/perl/model-home.pl?XID=M:products:crmportal&LOC=3&mdl=someModel
">
/usr/local/lib/ruby19/1.9.1/rexml/text.rb:155:in `block in check'
/usr/local/lib/ruby19/1.9.1/rexml/text.rb:153:in `scan'
/usr/local/lib/ruby19/1.9.1/rexml/text.rb:153:in `check'
/usr/local/lib/ruby19/1.9.1/rexml/text.rb:125:in `parent='
/usr/local/lib/ruby19/1.9.1/rexml/parent.rb:19:in `add'
/usr/local/lib/ruby19/1.9.1/rexml/parsers/treeparser.rb:45:in `parse'
/usr/local/lib/ruby19/1.9.1/rexml/document.rb:228:in `build'
/usr/local/lib/ruby19/1.9.1/rexml/document.rb:43:in `initialize'
x.rb:4:in `new'
x.rb:4:in `<main>'
...
Illegal character '&' in raw string "
http://www.somecompany.com/US/perl/model-home.pl?XID=M:products:crmportal&LOC=3&mdl=someModel
"
Line: 8
Position: 221
Last 80 unconsumed characters:
</link>
         from 
/usr/local/lib/ruby19/1.9.1/rexml/parsers/treeparser.rb:20:in `parse'
         from /usr/local/lib/ruby19/1.9.1/rexml/document.rb:228:in `build'
         from /usr/local/lib/ruby19/1.9.1/rexml/document.rb:43:in 
`initialize'
         from x.rb:4:in `new'
         from x.rb:4:in `<main>'

robert@fussel ~
$

How did you manage to get REXML parse this?

Kind regards

	robert

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