From: Robert Klemme <shortcutter@...>
Date: 2008-09-16T05:12:47+09:00
Subject: Re: ruby / rexml / xpath bug?

On 15.09.2008 21:38, altinsel wrote:
> I'm doing something I would think is very straight-forward but am
> getting the strangest result.  I'm wondering if anyone could help to
> let me know if this is a bug or if I'm doing something I can't see..
> 
> I copied a Google Maps script from Google Maps with Rails and Ajax
> straight from code.  It requests a geocoding from Google and parses
> the XML using rexml.  When it gets to the address with 2 results, the
> "each" iterator is looping through, but on the second element is
> giving me info from the first.  below is the script exactly.
> 
> require 'open-uri'
> require 'rexml/document'
> 
> # Retrieve geocode information for all records in the Stores table
> task :google_geocode => :environment do
>   api_key=GOOGLE_MAPS_KEY
> 
>     (Store.find :all).each do |store|
> 
>       puts "\nStore: #{store.name}"
>       puts "Source Address: #{store.full_address}"
> 
>       xml=open("http://maps.google.com/maps/geo?
> q=#{CGI.escape(store.full_address)}&output=xml&key=#{api_key}").read
>       doc=REXML::Document.new(xml)
> 
>       puts "Status: "+doc.elements['//kml/Response/Status/code'].text
> 
>       if doc.elements['//kml/Response/Status/code'].text != '200'
>         puts "Unable to parse Google response for #{store.name}"
>       else
>         doc.root.each_element('//Response') do |response|
>           response.each_element('//Placemark') do |place|
>             #there are 2 "Placemarks" in one particular "Response"
>             lng,lat=place.elements['Point/
> coordinates'].text.split(',')

This seems weird: you search for potential multiple elements but use 
method "text" on the result.  Not sure what this is going to yield but 
I'd rather iterate.

>             puts "  Result Address: " << place.elements['//
> address'].text

see above

>             # the address, lat and lng come from the 1st element twice
>             puts "  ID: " << place.attributes['id']
>             # .. but the 'id' is correct.
>             puts "  Latitude: #{lat}"
>             puts "  Longitude: #{lng}"
>           end # end each place
>         end # end each response
>       end # end if result == 200
>     end # end each store
>   end # end rake task
> 
> #####
> 
> What I don't understand, is that the XML for each "place" is correct,
> but the place.elements['//address'] keeps finding the previous
> iterations information. How can this be?

Hm, weird.  Are you sure the XML is as expected?

Btw, you can combine searching for //Response and //Placemark in one 
since you do not do anything with "Response".

Kind regards

	robert