Module: JSON::LD::Compact

Includes:
Utils
Included in:
API
Defined in:
vendor/bundler/ruby/2.6.0/bundler/gems/json-ld-94ee7791d19f/lib/json/ld/compact.rb

Constant Summary collapse

CONTAINER_MAPPING_ID =

The following constant is used to reduce object allocations in #compact below

%w(@id).freeze
CONTAINER_MAPPING_INDEX =
%w(@index).freeze
CONTAINER_MAPPING_LANGUAGE =
%w(@language).freeze
CONTAINER_MAPPING_LANGUAGE_INDEX_ID_TYPE =
Set.new(%w(@language @index @id @type)).freeze
CONTAINER_MAPPING_LIST =
%w(@list).freeze
CONTAINER_MAPPING_TYPE =
%w(@type).freeze

Instance Method Summary collapse

Methods included from Utils

#add_value, #as_array, #as_resource, #blank_node?, #compare_values, #graph?, #has_property, #has_value, #index?, #list?, #node?, #node_or_ref?, #node_reference?, #simple_graph?, #value?

Instance Method Details

#compact(element, property: nil, ordered: false) ⇒ Array, Hash

This algorithm compacts a JSON-LD document, such that the given context is applied. This must result in shortening any applicable IRIs to terms or compact IRIs, any applicable keywords to keyword aliases, and any applicable JSON-LD values expressed in expanded form to simple values such as strings or numbers.

Parameters:

  • element (Array, Hash)
  • property (String)

    (nil)

  • ordered (Boolean)

    (true) Ensure output objects have keys ordered properly

Returns:



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# File 'vendor/bundler/ruby/2.6.0/bundler/gems/json-ld-94ee7791d19f/lib/json/ld/compact.rb', line 23

def compact(element, property: nil, ordered: false)
  #if property.nil?
  #  log_debug("compact") {"element: #{element.inspect}, ec: #{context.inspect}"}
  #else
  #  log_debug("compact") {"property: #{property.inspect}"}
  #end

  # If the term definition for active property itself contains a context, use that for compacting values.
  input_context = self.context

  case element
  when Array
    #log_debug("") {"Array #{element.inspect}"}
    result = element.map {|item| compact(item, property: property, ordered: ordered)}.compact

    # If element has a single member and the active property has no
    # @container mapping to @list or @set, the compacted value is that
    # member; otherwise the compacted value is element
    if result.length == 1 &&
       !context.as_array?(property) && @options[:compactArrays]
      #log_debug("=> extract single element: #{result.first.inspect}")
      result.first
    else
      #log_debug("=> array result: #{result.inspect}")
      result
    end
  when Hash
    # Otherwise element is a JSON object.

    # @null objects are used in framing
    return nil if element.key?('@null')

    # Revert any previously type-scoped (non-preserved) context
    if context.previous_context && !element.key?('@value') && element.keys != %w(@id)
      self.context = context.previous_context
    end

    # Look up term definintions from property using the original type-scoped context, if it exists, but apply them to the now current previous context
    td = input_context.term_definitions[property] if property
    self.context = context.parse(td.context, override_protected: true) if td && td.context

    if element.key?('@id') || element.key?('@value')
      result = context.compact_value(property, element, log_depth: @options[:log_depth])
      if !result.is_a?(Hash) || context.coerce(property) == '@json'
        #log_debug("") {"=> scalar result: #{result.inspect}"}
        return result
      end
    end

    # If expanded property is @list and we're contained within a list container, recursively compact this item to an array
    if list?(element) && context.container(property) == CONTAINER_MAPPING_LIST
      return compact(element['@list'], property: property, ordered: ordered)
    end

    inside_reverse = property == '@reverse'
    result, nest_result = {}, nil

    # Apply any context defined on an alias of @type
    # If key is @type and any compacted value is a term having a local context, overlay that context.
    Array(element['@type']).
      map {|expanded_type| context.compact_iri(expanded_type, vocab: true)}.
      sort.
      each do |term|
      term_context = input_context.term_definitions[term].context if input_context.term_definitions[term]
      self.context = context.parse(term_context, propagate: false) if term_context
    end

    element.keys.opt_sort(ordered: ordered).each do |expanded_property|
      expanded_value = element[expanded_property]
      #log_debug("") {"#{expanded_property}: #{expanded_value.inspect}"}

      if expanded_property == '@id'
        compacted_value = Array(expanded_value).map {|expanded_id| context.compact_iri(expanded_id)}

        kw_alias = context.compact_iri('@id', vocab: true)
        as_array = compacted_value.length > 1
        compacted_value = compacted_value.first unless as_array
        result[kw_alias] = compacted_value
        next
      end

      if expanded_property == '@type'
        compacted_value = Array(expanded_value).map {|expanded_type| input_context.compact_iri(expanded_type, vocab: true)}

        kw_alias = context.compact_iri('@type', vocab: true)
        as_array = (context.processingMode == 'json-ld-1.1' &&
                    context.as_array?(kw_alias) &&
                    !value?(element)) ||
                   compacted_value.length > 1
        compacted_value = compacted_value.first unless as_array
        result[kw_alias] = compacted_value
        next
      end

      if expanded_property == '@reverse'
        compacted_value = compact(expanded_value, property: '@reverse', ordered: ordered)
        #log_debug("@reverse") {"compacted_value: #{compacted_value.inspect}"}
        # handle double-reversed properties
        compacted_value.each do |prop, value|
          if context.reverse?(prop)
            add_value(result, prop, value,
              property_is_array: context.as_array?(prop) || !@options[:compactArrays])
            compacted_value.delete(prop)
          end
        end

        unless compacted_value.empty?
          al = context.compact_iri('@reverse', quiet: true)
          #log_debug("") {"remainder: #{al} => #{compacted_value.inspect}"}
          result[al] = compacted_value
        end
        next
      end

      if expanded_property == '@preserve'
        # Compact using `property`
        compacted_value = compact(expanded_value, property: property, ordered: ordered)
        #log_debug("@preserve") {"compacted_value: #{compacted_value.inspect}"}

        unless compacted_value.is_a?(Array) && compacted_value.empty?
          result['@preserve'] = compacted_value
        end
        next
      end

      if expanded_property == '@index' && context.container(property) == CONTAINER_MAPPING_INDEX
        #log_debug("@index") {"drop @index"}
        next
      end

      # Otherwise, if expanded property is @index, @value, or @language:
      if expanded_property == '@index' || expanded_property == '@value' || expanded_property == '@language'
        al = context.compact_iri(expanded_property, vocab: true, quiet: true)
        #log_debug(expanded_property) {"#{al} => #{expanded_value.inspect}"}
        result[al] = expanded_value
        next
      end

      if expanded_value.empty?
        item_active_property =
          context.compact_iri(expanded_property,
                              value: expanded_value,
                              vocab: true,
                              reverse: inside_reverse,
                              log_depth: @options[:log_depth])

        if nest_prop = context.nest(item_active_property)
          result[nest_prop] ||= {}
          add_value(result[nest_prop], item_active_property, [],
            property_is_array: true)
        else
          add_value(result, item_active_property, [],
            property_is_array: true)
        end
      end

      # At this point, expanded value must be an array due to the Expansion algorithm.
      expanded_value.each do |expanded_item|
        item_active_property =
          context.compact_iri(expanded_property,
                              value: expanded_item,
                              vocab: true,
                              reverse: inside_reverse,
                              log_depth: @options[:log_depth])


        nest_result = if nest_prop = context.nest(item_active_property)
          # FIXME??: It's possible that nest_prop will be used both for nesting, and for values of @nest
          result[nest_prop] ||= {}
        else
          result
        end

        container = context.container(item_active_property)
        as_array = !@options[:compactArrays] || context.as_array?(item_active_property)

        value = case
        when list?(expanded_item) then expanded_item['@list']
        when graph?(expanded_item) then expanded_item['@graph']
        else expanded_item
        end

        compacted_item = compact(value, property: item_active_property, ordered: ordered)
        #log_debug("") {" => compacted key: #{item_active_property.inspect} for #{compacted_item.inspect}"}

        # handle @list
        if list?(expanded_item)
          compacted_item = as_array(compacted_item)
          unless container == CONTAINER_MAPPING_LIST
            al = context.compact_iri('@list', vocab: true, quiet: true)
            compacted_item = {al => compacted_item}
            if expanded_item.has_key?('@index')
              key = context.compact_iri('@index', vocab: true, quiet: true)
              compacted_item[key] = expanded_item['@index']
            end
          else
            add_value(nest_result, item_active_property, compacted_item,
              value_is_array: true, allow_duplicate: true)
              next
          end
        end

        # Graph object compaction cases:
        if graph?(expanded_item)
          if container.include?('@graph') &&
            (container.include?('@id') || container.include?('@index') && simple_graph?(expanded_item))
            # container includes @graph and @id
            map_object = nest_result[item_active_property] ||= {}
            # If there is no @id, create a blank node identifier to use as an index
            map_key = if container.include?('@id') && expanded_item['@id']
              context.compact_iri(expanded_item['@id'], quiet: true)
            elsif container.include?('@index') && expanded_item['@index']
              context.compact_iri(expanded_item['@index'], quiet: true)
            else
              context.compact_iri('@none', vocab: true, quiet: true)
            end
            add_value(map_object, map_key, compacted_item,
              property_is_array: as_array)
          elsif container.include?('@graph') && simple_graph?(expanded_item)
            # container includes @graph but not @id or @index and value is a simple graph object
            if compacted_item.is_a?(Array) && compacted_item.length > 1
              # Mutple objects in the same graph can't be represented directly, as they would be interpreted as two different graphs. Need to wrap in @included.
              included_key = context.compact_iri('@included', vocab: true).to_s
              compacted_item = {included_key => compacted_item}
            end
            # Drop through, where compacted_item will be added
            add_value(nest_result, item_active_property, compacted_item,
              property_is_array: as_array)
          else
            # container does not include @graph or otherwise does not match one of the previous cases, redo compacted_item
            al = context.compact_iri('@graph', vocab: true, quiet: true)
            compacted_item = {al => compacted_item}
            if expanded_item['@id']
              al = context.compact_iri('@id', vocab: true, quiet: true)
              compacted_item[al] = context.compact_iri(expanded_item['@id'], vocab: false, quiet: true).to_s
            end
            if expanded_item.has_key?('@index')
              key = context.compact_iri('@index', vocab: true, quiet: true)
              compacted_item[key] = expanded_item['@index']
            end
            add_value(nest_result, item_active_property, compacted_item,
              property_is_array: as_array)
          end
        elsif container.any? { |key| CONTAINER_MAPPING_LANGUAGE_INDEX_ID_TYPE.include?(key) } && !container.include?('@graph')
          map_object = nest_result[item_active_property] ||= {}
          c = container.first
          container_key = context.compact_iri(c, vocab: true, quiet: true)
          compacted_item = case container
          when CONTAINER_MAPPING_ID
            map_key = compacted_item[container_key]
            compacted_item.delete(container_key)
            compacted_item
          when CONTAINER_MAPPING_INDEX
            index_key = context.term_definitions[item_active_property].index || '@index'
            if index_key == '@index'
              map_key = expanded_item['@index']
              compacted_item.delete(container_key) if compacted_item.is_a?(Hash)
            else
              container_key = context.compact_iri(index_key, vocab: true, quiet: true)
              map_key, *others = Array(compacted_item[container_key])
              if map_key.is_a?(String)
                case others.length
                when 0 then compacted_item.delete(container_key)
                when 1 then compacted_item[container_key] = others.first
                else        compacted_item[container_key] = others
                end
              else
                map_key = context.compact_iri('@none', vocab: true, quiet: true)
              end
            end
            # Note, if compacted_item is a node reference and key is @id-valued, then this could be compacted further.
            compacted_item
          when CONTAINER_MAPPING_LANGUAGE
            map_key = expanded_item['@language']
            value?(expanded_item) ? expanded_item['@value'] : compacted_item
          when CONTAINER_MAPPING_TYPE
            map_key, *types = Array(compacted_item[container_key])
            case types.length
            when 0 then compacted_item.delete(container_key)
            when 1 then compacted_item[container_key] = types.first
            else        compacted_item[container_key] = types
            end

            # if compacted_item contains a single entry who's key maps to @id, then recompact the item without @type
            if compacted_item.keys.length == 1 && expanded_item.keys.include?('@id')
              compacted_item = compact({'@id' => expanded_item['@id']}, property: item_active_property)
            end
            compacted_item
          end
          map_key ||= context.compact_iri('@none', vocab: true, quiet: true)
          add_value(map_object, map_key, compacted_item,
            property_is_array: as_array)
        else
          add_value(nest_result, item_active_property, compacted_item,
            property_is_array: as_array)
        end
      end
    end

    result
  else
    # For other types, the compacted value is the element value
    #log_debug("compact") {element.class.to_s}
    element
  end

ensure
  self.context = input_context
end