Traverse xml structure to determine if a certain text node exists

Question

Alright I have an xml document that looks something like this:

    <xml>
     <list>
      <partner>
       <name>Some Name</name>
       <status>active</status>
       <id>0</id>
      </partner>
      <partner>
       <name>Another Name</name>
       <status>active</status>
       <id>1</id>
      </partner>
    </list>
   </xml>

I am using ruby's lib-xml to parse it. I want to find if there is a partner with the name 'Some Name' in a quick and ruby idiomatic way.

How can I do this in one line or ruby code, assuming i have a the document parsed in a variable named document.. Such that i can call document.find(xpath) to retrieve nodes. I have had to do this multiple times in slightly different scenarios and now its starting to bug me.

I know i can do the following (but its ugly)

 found = false
 document.find('//partner/name').each do |name|
  if (name.content == 'Some Name')
   found = true
   break
  end
 end
 assert(found, "Some Name should have been found")

but i find this really ugly. I thought about using the enumeration include? mixin method but that still won't work because I need to get the .content field of each node as opposed to the actual node... While writing this, I though of this (but it seems somewhat inefficient albeit elegant)

found = document.find('//partner/name').collect{|name| name.content}.member?("Some Name")

Are there any other ways of doing this?

Answer 1

I would use a language that natively operates on XML (XQuery for example). With XQuery it is possible to formulate this sort of queries over xml data in a concise and elegant way.

Answer 2

What about this?

found = document.find("//partner[name='Some Name']").empty?

Answer 3

I tried this solution:

 found = document.find("//partner[name='Some Name']") != nil

but I got an error saying the xpath expression was invalid. However, i was reading some xpath documentation it it looks like you can call a text() function in the expression to get the text node. I tried the following and it appears to work:

 found = document.find("//partner/name/text()='Some Name'")

found actually is not a xml node but a true/false object so this works.