Class: Scrubyt::TreeFilter

Inherits:
BaseFilter show all
Defined in:
lib/scrubyt/core/scraping/filters/tree_filter.rb

Constant Summary

Constants inherited from BaseFilter

BaseFilter::EXAMPLE_TYPE_CHILDREN, BaseFilter::EXAMPLE_TYPE_COMPOUND, BaseFilter::EXAMPLE_TYPE_IMAGE, BaseFilter::EXAMPLE_TYPE_REGEXP, BaseFilter::EXAMPLE_TYPE_STRING, BaseFilter::EXAMPLE_TYPE_XPATH

Instance Attribute Summary

Attributes inherited from BaseFilter

#constraints, #example, #example_type, #final_result, #parent_pattern, #regexp, #temp_sink, #xpath

Instance Method Summary collapse

Methods inherited from BaseFilter

create, #method_missing, #throw_method_missing

Dynamic Method Handling

This class handles dynamic methods through the method_missing method in the class Scrubyt::BaseFilter

Instance Method Details

#evaluate(source) ⇒ Object 



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# File 'lib/scrubyt/core/scraping/filters/tree_filter.rb', line 4

def evaluate(source)
  return [@final_result] if @final_result
  #Crude hack! Drop it after it will be supported in Hpricot
  if @xpath =~ /.+\/@.+$/
    @example = @xpath
    @xpath = @xpath.scan(/^(.+?)\/@/)[0][0]
  end
  result = source/@xpath

  Scrubyt.log :ACTION, "Evaluating #{@parent_pattern.name} with #{@xpath}"

  xpath_results = Hpricot::Elements === result ? result : [result]

  if @example =~ /.+\/@.+$/
    result_attribute = @example.scan(/.+\/@(.+?)$/)[0][0]
    xpath_results.map! {|r| r.attributes[result_attribute] }
  end
  if @regexp == nil
    xpath_results
  else
    regexp_results = []
    xpath_results.each do |entry|
      text = SharedUtils.prepare_text_for_comparison(result.inner_html)
      if text =~ @regexp
        regexp_results << $1
      end
    end
    regexp_results
  end
end

#generate_regexp_for_example ⇒ Object 



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# File 'lib/scrubyt/core/scraping/filters/tree_filter.rb', line 35

def generate_regexp_for_example
  return if @example_type != EXAMPLE_TYPE_STRING
  return if @temp_sink.nil?
  return if @temp_sink.is_a? String
  return if @example =~ /.+\[.+\]$/

  text = SharedUtils.prepare_text_for_comparison(@temp_sink.inner_html.gsub(/<.*?>/, ''))
  match_range = @temp_sink.match_data.begin(0)..@temp_sink.match_data.end(0)
  return if match_range == (0..text.length)

  @regexp = text
  @temp_sink.changing_ranges.sort.reverse.each do |range|
    @regexp[range] = if range == match_range then '<<<regexp_selection>>>' else '<<<regexp_changing>>>' end
  end
  @regexp = Regexp.escape(@regexp)
  @regexp = @regexp.gsub('<<<regexp_changing>>>', '.*?')
  @regexp = @regexp.gsub('<<<regexp_selection>>>', '(.*?)')
  @regexp = '^' + @regexp + '$'
  @regexp = /#{@regexp}/
end

#generate_relative_XPath(parent_xpath) ⇒ Object 



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# File 'lib/scrubyt/core/scraping/filters/tree_filter.rb', line 130

def generate_relative_XPath(parent_xpath)
  parent_xpath = XPathUtils.to_full_XPath(@parent_pattern.extractor.get_hpricot_doc,
                                          parent_xpath,
                                          @parent_pattern.parent.generalize) if parent_xpath =~ /(\[@.+=.+\])$/
  @xpath = XPathUtils.generate_relative_XPath_from_XPaths(parent_xpath, @xpath) if (@xpath =~ /^\/html/) #TODO: should not rely on <html> being the root node
end

#generate_XPath_for_example(next_page_example = false) ⇒ Object

For all the tree patterns, generate an XPath based on the given example Also this method should not be called directly; It is automatically called for every tree pattern directly after wrapper definition



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# File 'lib/scrubyt/core/scraping/filters/tree_filter.rb', line 60

def generate_XPath_for_example(next_page_example=false)
  #puts "generating example for: #{@parent_pattern.name}"
  #puts @example_type
  case @example_type
  when EXAMPLE_TYPE_XPATH
    @xpath = @example
  when EXAMPLE_TYPE_STRING
    @temp_sink = SimpleExampleLookup.find_node_from_text(@parent_pattern.extractor.get_hpricot_doc,
                                                         @example,
                                                         next_page_example)
    return if @temp_sink == nil
    if @temp_sink.is_a? String
      @final_result = @temp_sink
      return
    end

    mark_changing_ranges = lambda { |element, range|
      element.instance_eval do
        @changing_ranges ||= [] << range
        def changing_ranges
          @changing_ranges
        end
      end
    }
    mark_changing_ranges.call(@temp_sink, @temp_sink.match_data.begin(0)..@temp_sink.match_data.end(0))
    write_indices = next_page_example ? true : !@parent_pattern.generalize
    @xpath = XPathUtils.generate_XPath(@temp_sink, nil, write_indices)
  when EXAMPLE_TYPE_CHILDREN
    current_example_index = 0
    loop do
      all_child_temp_sinks = []
      @parent_pattern.children.each do |child_pattern|
        all_child_temp_sinks << child_pattern.filters[current_example_index].temp_sink if child_pattern.filters[current_example_index].temp_sink
      end
      result = all_child_temp_sinks.pop
      if all_child_temp_sinks.empty?
        result = result.parent
      else
        all_child_temp_sinks.each do |child_sink|
          result = XPathUtils.lowest_common_ancestor(result, child_sink)
        end
      end
      xpath = @parent_pattern.generalize ? XPathUtils.generate_XPath(result, nil, false) :
                                           XPathUtils.generate_XPath(result, nil, true)
      if @parent_pattern.filters.size < current_example_index + 1
        @parent_pattern.filters << Scrubyt::BaseFilter.create(@parent_pattern)
      end
      @parent_pattern.filters[current_example_index].xpath = xpath
      @parent_pattern.filters[current_example_index].temp_sink = result
      @parent_pattern.children.each do |child_pattern|
      next if child_pattern.type == :detail_page
        child_pattern.filters[current_example_index].xpath =
        child_pattern.generalize ? XPathUtils.generate_generalized_relative_XPath(child_pattern.filters[current_example_index].temp_sink, result) :
        XPathUtils.generate_relative_XPath(child_pattern.filters[current_example_index].temp_sink, result)
      end
      break if @parent_pattern.children[0].filters.size == current_example_index + 1
      current_example_index += 1
    end
  when EXAMPLE_TYPE_IMAGE
    @temp_sink = XPathUtils.find_image(@parent_pattern.extractor.get_hpricot_doc, @example)
    @xpath = XPathUtils.generate_XPath(@temp_sink, nil, true)
  when EXAMPLE_TYPE_COMPOUND
    @temp_sink = CompoundExampleLookup.find_node_from_compund_example(@parent_pattern.extractor.get_hpricot_doc,
                                                                      @example,
                                                                      next_page_example)
    @xpath = @parent_pattern.generalize ? XPathUtils.generate_XPath(@temp_sink, nil, false) :
                                          XPathUtils.generate_XPath(@temp_sink, nil, true)
  end
end

#to_sexp ⇒ Object 



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# File 'lib/scrubyt/core/scraping/filters/tree_filter.rb', line 137

def to_sexp
  if @example =~ /.+\[@.+\]$/
    [:str, "#{@xpath}/@#{@example.scan(/\[@(.+?)\]/)[0][0]}"]
  else
    [:str, @xpath]
  end
end