Module: ActiveFedora::Finders::ClassMethods

Defined in:
lib/active_fedora_finders.rb

Instance Method Summary collapse

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method_id, *arguments, &block) ⇒ Object

adapted from ActiveRecord::DynamicMatchers



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# File 'lib/active_fedora_finders.rb', line 88

def method_missing(method_id, *arguments, &block)
  if match = (ActiveRecord::DynamicFinderMatch.match(method_id) || ActiveRecord::DynamicScopeMatch.match(method_id))
    attribute_names = match.attribute_names
    normalize_attribute_names!(attribute_names)
    super unless all_attributes_exists?(attribute_names)
    if !(match.is_a?(ActiveRecord::DynamicFinderMatch) && match.instantiator? && arguments.first.is_a?(Hash)) && arguments.size < attribute_names.size
      method_trace = "#{__FILE__}:#{__LINE__}:in `#{method_id}'"
      backtrace = [method_trace] + caller
      raise ArgumentError, "wrong number of arguments (#{arguments.size} for #{attribute_names.size})", backtrace
    end
    if match.respond_to?(:scope?) && match.scope?
      self.class_eval <<-METHOD, __FILE__, __LINE__ + 1
        def self.#{method_id}(*args)                                    # def self.scoped_by_user_name_and_password(*args)
          attributes = Hash[[:#{attribute_names.join(',:')}].zip(args)] #   attributes = Hash[[:user_name, :password].zip(args)]
                                                                        #
          scoped(:conditions => attributes)                             #   scoped(:conditions => attributes)
        end                                                             # end
      METHOD
      send(method_id, *arguments)
    elsif match.finder?
      find_by_attributes(match, attribute_names, *arguments, &block)
    elsif match.instantiator?
      find_or_instantiator_by_attributes(match, attribute_names, *arguments, &block)
    end
  else
    super
  end
end

Instance Method Details

#all_attributes_exists?(attribute_names) ⇒ Boolean

this method is patterned after an analog in ActiveRecord::DynamicMatchers

Returns:

  • (Boolean) 


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# File 'lib/active_fedora_finders.rb', line 78

def all_attributes_exists?(attribute_names)
  attribute_names.reduce(true) {|result, att| ALL_FIELDS.include? att or SUPPORTED_ALTS.include? att}
end

#fcrepo_find(match, args) ⇒ Object 



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# File 'lib/active_fedora_finders.rb', line 42

def fcrepo_find(match, args)
  parms = args.dup
  maxResults = (match.nil? or match.finder == :first) ? 1 : 25 # find_all and find_last not yet supported    
  query = ""
  parms.each { |key, val|
    if SINGLE_VALUE_FIELDS.include? key
      query.concat "#{key.to_s}=#{val.to_s} "
    else
      query.concat "#{key.to_s}~#{val.to_s} "
    end
  }
  query.strip!
  results = []
  if ActiveFedora.config.sharded?
    (0...ActiveFedora.config.credentials.length).each {|ix|
      ActiveFedora::Base.fedora_connection[ix] ||= ActiveFedora::RubydoraConnection.new(ActiveFedora.config.credentials[ix])
      rubydora = ActiveFedora::Base.fedora_connection[ix].connection
      if results.length <= maxResults
        results.concat process_results(rubydora.find_objects(:query=>query,:pid=>'true', :maxResults=>maxResults))
      end
    }
  else
    ActiveFedora::Base.fedora_connection[0] ||= ActiveFedora::RubydoraConnection.new(ActiveFedora.config.credentials)
    rubydora = ActiveFedora::Base.fedora_connection[0].connection
    results.concat process_results(rubydora.find_objects(:query=>query,:pid=>'true', :maxResults=>maxResults))
  end
  return (maxResults == 1) ? results[0] : results
end

#find_by_attributes(match, attribute_names, *args) ⇒ Object

modeled after ActiveRecord::FinderMethods.find_by_attributes



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# File 'lib/active_fedora_finders.rb', line 31

def find_by_attributes(match, attribute_names, *args)
  conditions = Hash[attribute_names.map {|a| [a, args[attribute_names.index(a)]]}]
  result = fcrepo_find(match, conditions)
  if match.bang? && result.blank?
    raise ActiveRecord::RecordNotFound, "Couldn't find #{self.name} with #{conditions.to_a.collect {|p| p.join(' = ')}.join(', ')}"
  else
    yield(result) if block_given?
    result
  end
end

#normalize_attribute_names!(attribute_names) ⇒ Object 



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# File 'lib/active_fedora_finders.rb', line 82

def normalize_attribute_names!(attribute_names)
  field_keys = attribute_names.map {|val| FIELD_KEYS[val] or val}
  attribute_names.replace field_keys
end

#process_results(results) ⇒ Object 



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# File 'lib/active_fedora_finders.rb', line 71

def process_results(results)
  results = Nokogiri::XML.parse(results)
  results = results.xpath('/f:result/f:resultList/f:objectFields/f:pid',{'f'=>"http://www.fedora.info/definitions/1/0/types/"})
  results.collect { |result| find_one(result.text) }
end