Class: RDig::UrlFilters::FilterChain

Inherits:
Object
  • Object
show all
Defined in:
lib/rdig/url_filters.rb

Instance Method Summary collapse

Constructor Details

#initialize(chain_config) ⇒ FilterChain

Returns a new instance of FilterChain.



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# File 'lib/rdig/url_filters.rb', line 6

def initialize(chain_config)
  @logger = RDig.logger
  @filters = []
  chain_config.each { |filter|
    case filter
    when Hash
      filter.each_pair { |f, args|
        add(f, args)
      }
    when Array
      args = filter
      filter = args.shift
      add(filter, args)
    else
      add(filter)
    end
  }
end

Instance Method Details

#add(filter, args = nil) ⇒ Object

add a filter and it’s args to the chain if args is a symbol, it is treated as a configuration key



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# File 'lib/rdig/url_filters.rb', line 27

def add(filter, args=nil)
  args = RDig.config.crawler.send(args) if args.is_a? Symbol
  case filter
  when Symbol
    if args.nil?
      @filters << lambda { |document|
        begin
          UrlFilters.send(filter, document)
        rescue Exception
          @logger.error "error in URL filter #{filter}: #{$!}"
          @logger.error $!.backtrace.join("\n")
          nil
        end
      }
    else
      @filters << lambda { |document|
        begin
          UrlFilters.send(filter, document, args)
        rescue Exception
          @logger.error "error in URL filter #{filter}: #{$!}"
          @logger.error $!.backtrace.join("\n")
          nil
        end
      }
    end
  when Class
    if args.nil?
      if filter.respond_to?(:instance)
        filter_instance = filter.instance
      else
        filter_instance = filter.new
      end
    else
      filter_instance = filter.new(args)
    end
    @filters << lambda { |document|
      filter_instance.apply(document)
    }
  end
end

#apply(document) ⇒ Object 



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# File 'lib/rdig/url_filters.rb', line 68

def apply(document)
  @filters.each { |filter|
    @logger.debug "running filter #{filter.inspect} on doc #{document.uri}"
    unless filter.call(document)
      @logger.debug "fail"
      return nil
    else
      @logger.debug 'OK'
    end
  }
  return document
end