Xpath to attributes

Ruby
1

Is there anyway to do generic xpath’s, for both elements and attributes
(ie //customer/phone/@type --> “home”)? REXML can do xpath to fetch
elements (rexml_element.text(’//customer/phone’)) but can’t seem to use
xpath to find attributes.

2

On Wed, 2006-02-22 at 10:33 +0900, [email protected] wrote:

Is there anyway to do generic xpath’s, for both elements and attributes
(ie //customer/phone/@type --> “home”)? REXML can do xpath to fetch
elements (rexml_element.text(’//customer/phone’)) but can’t seem to use
xpath to find attributes.

d = REXML::Document.new <<EOX
  <customer>
    <phone type='home'>0115</phone>
    <phone type='mobi'>07807</phone>
  </customer>
EOX

m = REXML::XPath.match(d, '//customer/phone[@type = "home"]')
p m.to_s
# => <phone type='home'>0115</phone>
3

[email protected] wrote:

Is there anyway to do generic xpath’s, for both elements and attributes
(ie //customer/phone/@type --> “home”)? REXML can do xpath to fetch
elements (rexml_element.text(’//customer/phone’)) but can’t seem to use
xpath to find attributes.

class Array; alias atr first; alias txt last end
class String
def xtag(s)
scan( %r!
< #{s} (?: \s+ ( [^>]* ) )? / >
|
< #{s} (?: \s+ ( [^>]* ) )? >
( .? ) </ #{s} >
!mx ).
map{ |unpaired, attr, data| h = { }
attr = ( unpaired || attr )
if attr
attr.scan( %r! ( \S+ ) = ( ["’] ) ( .? ) \2 !x ){ |k,q,v|
h[k] = v }
end
[ h, data ]
}
end
def xpath(s)
s.scan(%r! [^/"]+ (?: “[^”]" )? !x).inject([[nil,self]]){|ary,str|
if “@” == str[0,1]
str =~ /@(.?)="(.*)"/
ary.select{|a,t| a[$1] == $2 }
else
return [] if [] == ary
ary[0].txt.xtag(str)
end
}
end
end

p DATA.read.xpath(‘customer/@loc=“south”/phone/@type=“mobi”’)

END

0115
07807


0319
09802

4

Thanks.

But I’d like to just extract the attribute value via Xpath.

If my Xpath is correct, I could just do ‘//customer/phone/@type’ to get
‘home’. Is there any way I can do this in Ruby?

5

[email protected] wrote:

Thanks.

But I’d like to just extract the attribute value via Xpath.

If my Xpath is correct, I could just do ‘//customer/phone/@type’ to get
‘home’. Is there any way I can do this in Ruby?

p DATA.read.xchain(‘customer/@loc=“south”/phone’).first.atr[‘type’]

END

0115
07807


0319

The rest:

class Array; alias atr first; alias txt last end
class String
def xtag(s)
result = []
scan( %r!
< #{s} (?: \s+ ( [^>]* ) )? / >
|
< #{s} (?: \s+ ( [^>]* ) )? >
( .? ) </ #{s} >
!mx )
{ |unpaired, attr, data| h = { }
attr = ( unpaired || attr )
attr.scan( %r{ ( \S+ ) = ( ["’] ) ( .? ) \2 }x ){ |k,q,v|
h[k] = v } if attr
block_given? ? ( yield [ h, data ] ) : result << [ h, data ]
}
result
end
def xchain(s)
s.scan(%r! [^/"]+ (?: “[^”]" )? !x).inject([[nil,self]]){|ary,str|
if “@” == str[0,1]
str =~ /@(.?)="(.*)"/
ary.select{|a,t| a[$1] == $2 }
else
return [] if [] == ary
ary[0].txt.xtag(str)
end
}
end
end