nokogiri-extractor

http://github.com/ethansr/nokogiri-extractor

SYNOPSIS:

  require 'nokogiri/extractor'
  doc = Nokogiri::XML.parse('<this is="cool">that</this>')
  doc.extractor!

  doc.extract('this') # => 'that'

  doc.extract('this', attr: :is) # => 'cool'

  doc.extract('this', regexp: /th(.*)/) # => 'at'

  doc.extract('this') {|text| text.upcase} #=> 'THAT'

DESCRIPTION:

This gem provides decoraters that add methods to Nokogiri to extract text from a Node or NodeSet in a structured way. Using Nokogiri's decorator functions, this can be done without any monkey patching (although we do provide a convenience method).

It handles a very common case in extracting information from structured documents where the required information is most easily acquired through the pattern of:

extract : document -> selector -> text

This has some suprising pitfalls, especially when elements and their attributes may or may not exist and when a series of operations are neccesary to coerce the text within an element into the desired format.

In these cases, we've found it useful to specify an entire path to the required data which can succeed or fail as a unit, rather than writing a series of defensive conditional statements.

# this:
if image = document.at_css('img')
  if alt_text = image[:alt]
    if image.match(/(\d*) kittens/)
      return $1
    end
  end
end

# can become:
document.extract 'img', attr: :alt, regexp: /(\d*) kittens/

More importantly, extract also accepts a block, allowing arbitrary work to be done if the desired data is found.

# Use whatever functions you need to do cleanup, return value may 
# whatever type you need.
document.extract('a', attr: :href) {|link| URI::parse(link)}

# Works with map
document.search('a').map { |anchor|
  anchor.extract('img', attr: :alt) { |alt_text| translate(alt_text)}
}

REQUIREMENTS:

nokogiri
andand

INSTALL:

$ rake install_gem
# gem install nokogiri-extractor (Some Day).

DEVELOPERS:

Gem creation is handled by the hoe gem.

After checking out the source, run:

  $ rake newb

This task will install any missing dependencies, run the tests/specs, and generate the RDoc.

LICENSE:

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.