Class: Yarrow::Content::CollectionExpander

Inherits:
Object
  • Object
show all
Includes:
Tools::FrontMatter
Defined in:
lib/yarrow/content/collection_expander.rb

Instance Method Summary collapse

Methods included from Tools::FrontMatter

#extract_split_content, #read_split_content

Constructor Details

#initialize(content_types = nil) ⇒ CollectionExpander

Returns a new instance of CollectionExpander.



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# File 'lib/yarrow/content/collection_expander.rb', line 6

def initialize(content_types=nil)
  @content_types = content_types || [
    Yarrow::Content::ContentType.from_name(:pages)
  ]
end

Instance Method Details

#build_content_nodes(graph, objects, type, parent_index) ⇒ Object 



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# File 'lib/yarrow/content/collection_expander.rb', line 126

def build_content_nodes(graph, objects, type, parent_index)
  # TODO: this may need to use a strategy that can be overriden
  content_type = Yarrow::Symbols.to_singular(type)

  # Process collected content objects and generate entity nodes
  objects.each do |name, sources|
    item_node = graph.create_node do |node|
      # TODO: Rename this to :entry and support similar fields to Atom
      node.label = :item
      node.props[:name] = name
      node.props[:type] = content_type

      meta = {}
      content = ""

      sources.each do |source|
        body, data = process_content(source.props[:entry])
        meta.merge!(data) unless data.nil?
        content << body unless body.nil?
      end

      if meta[:url]
        # If a URL is explicitly proided in metadata then use it
        node.props[:url] = meta[:url]
      elsif meta[:permalink]
        # Support for legacy permalink attribute
        node.props[:url] = meta[:permalink]
      else
        # Default URL generation strategy when no explicit URL is provided
        # TODO: collection nodes need URL generation too
        # TODO: replace this with URL generation strategy
        # TODO: slug vs name - why do some nodes have 2 and some 3 props?
        node.props[:url] = if parent_index.props[:name].to_sym == parent_index.props[:type]
          "/#{parent_index.props[:type]}/#{name}"
        else
          "/#{parent_index.props[:type]}/#{parent_index.props[:slug]}/#{name}"
        end
      end

      # For now, we are storing title, url, etc on the top-level item.
      node.props[:title] = meta[:title]

      # TODO: What belongs on the entity and what belongs on the item?
      entity_props = meta.merge(body: content, name: meta[:id], url: node.props[:url])


      # TODO: consider whether to provide `body` on the item/document or at
      # the custom content type level.
      begin
        content_struct = Yarrow::Symbols.to_const(content_type)
      rescue
        # No immutable struct found: fall back to slower dynamically typed open struct
        require "ostruct"
        content_struct = OpenStruct
      end

      node.props[:entity] = content_struct.new(entity_props)
    end

    # Connect entity with source content
    sources.each do |source|
      graph.create_edge do |edge|
        edge.label = :source
        edge.from = item_node
        edge.to = source.id
      end
    end

    # Connect entity with parent collection
    graph.create_edge do |edge|
      edge.label = :child
      edge.from = parent_index
      edge.to = item_node
    end
  end
end

#expand(graph) ⇒ Object 



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# File 'lib/yarrow/content/collection_expander.rb', line 12

def expand(graph)
  @content_types.each do |content_type|
    expand_nested(graph, content_type)
  end
end

#expand_nested(graph, content_type) ⇒ Object 



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# File 'lib/yarrow/content/collection_expander.rb', line 18

def expand_nested(graph, content_type)
  type = content_type.collection
  exts = content_type.extensions

  # If match path represents entire content dir, then include the entire
  # content dir instead of scanning from a subfolder matching the name of
  # the collection.
  start_node = if content_type.match_path == "."
    graph.n(:root)
  else
    graph.n(:root).out(name: type.to_s)
  end

  # Extract metadata from given start node
  data = extract_metadata(start_node, type)

  # Collects all nested collections in the subgraph for this content type
  subcollections = {}
  index = nil

  # Define alias for accessing metadata in the loop
  metadata = data

  # Scan and collect all nested directories under the top level source
  start_node.depth_first.each do |node|
    if node.label == :directory
      # Check if this entry has metadata defined at the top level
      if data[:collections]
        item = data[:collections].find { |c| c[:slug] == node.props[:slug] }
        metadata = item if item
      end

      # Create a collection node representing a collection of documents
      index = graph.create_node do |collection_node|
        collection_node.label = :collection
        collection_node.props[:type] = type
        collection_node.props[:name] = node.props[:name]
        collection_node.props[:slug] = node.props[:slug]
        collection_node.props[:title] = metadata[:title]

        # Override default status so that mapped index collections always show
        # up in the resulting document manifest, when they don’t have
        # associated metadata. This is the opposite of how individual pieces
        # of content behave (default to draft status if one isn’t supplied).
        collection_node.props[:status] = if data[:status]
          data[:status]
        else
          "published"
        end

        # TODO: URL generation might need to happen elsewhere
        collection_node.props[:url] = if data[:url]
          data[:url]
        else
          "#{node.props[:path].split('./content').last}/"
        end
      end

      # Add this collection id to the lookup table for edge construction
      subcollections[node.props[:path]] = index

      # Join the collection to its parent
      unless node.props[:slug] == type.to_s || !subcollections.key?(node.props[:entry].parent.to_s)
        graph.create_edge do |edge|
          edge.label = :child
          edge.from = subcollections[node.props[:entry].parent.to_s].id
          edge.to = index.id
        end
      end
    end
  end

  subcollections.each do |path, index|
    # Group files matching the same slug under a common key
    objects = graph.n(path: path).out(:file).all.select do |file|
      file.props[:name].end_with?(*exts)
    end.group_by do |file|
      file.props[:slug]
    end

    build_content_nodes(graph, objects, type, index)
  end
end

#extract_metadata(node, type) ⇒ Object

Extract collection level configuration/metadata from the root node for this content type.



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# File 'lib/yarrow/content/collection_expander.rb', line 104

def extract_metadata(node, type)
  # TODO: support _index or _slug convention as well
  meta_file = node.out(slug: type.to_s).first

  if meta_file
    # Process metadata and add it to the collection node
    # TODO: pass in content converter object
    # TODO: index/body content by default if extracted from frontmatter
    body, data = process_content(meta_file.props[:entry])
  else
    # Otherwise, assume default collection behaviour
    data = {}
  end

  # Generate a default title if not provided in metadata
  unless data.key?(:title)
    data[:title] = type.to_s.capitalize
  end

  data
end

#process_content(path) ⇒ Object

Workaround for handling meta and content source in multiple files or a single file with front matter.



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# File 'lib/yarrow/content/collection_expander.rb', line 205

def process_content(path)
  case path.extname
  when '.htm', '.md'
    read_split_content(path.to_s, symbolize_keys: true)
  # when '.md'
  #   body, data = read_split_content(path.to_s, symbolize_keys: true)
  #   [Kramdown::Document.new(body).to_html, data]
  when '.yml'
    [nil, YAML.load(File.read(path.to_s), symbolize_names: true)]
  end
end