Module: Nanoc::Helpers::Capturing
- Included in:
- Filtering, HTMLEscape, Rendering
- Defined in:
- lib/nanoc/helpers/capturing.rb
Overview
Provides functionality for “capturing” content in one place and reusing this content elsewhere.
For example, suppose you want the sidebar of your site to contain a short summary of the item. You could put the summary in the meta file, but that’s not possible when the summary contains eRuby. You could also put the sidebar inside the actual item, but that’s not very pretty. Instead, you write the summary on the item itself, but capture it, and print it in the sidebar layout.
This helper has been tested with ERB and Haml. Other filters may not work correctly.
Instance Method Summary collapse
-
#capture(&block) ⇒ String
Evaluates the given block and returns its contents.
-
#content_for(*args, &block) ⇒ Object
Instance Method Details
#capture(&block) ⇒ String
Evaluates the given block and returns its contents. The contents of the block is not outputted.
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# File 'lib/nanoc/helpers/capturing.rb', line 132 def capture(&block) # Get erbout so far erbout = eval('_erbout', block.binding) erbout_length = erbout.length # Execute block yield # Get new piece of erbout erbout_addition = erbout[erbout_length..-1] # Remove addition erbout[erbout_length..-1] = '' # Depending on how the filter outputs, the result might be a # single string or an array of strings (slim outputs the latter). erbout_addition = erbout_addition.join if erbout_addition.is_a? Array # Done. erbout_addition end |
#content_for(name, params = {}, &block) ⇒ void #content_for(item, name) ⇒ String
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# File 'lib/nanoc/helpers/capturing.rb', line 62 def content_for(*args, &block) if block_given? # Set content # Get args case args.size when 1 name = args[0] params = {} when 2 name = args[0] params = args[1] else raise ArgumentError, 'expected 1 or 2 argument (the name ' \ "of the capture, and optionally params) but got #{args.size} instead" end name = args[0] existing_behavior = params.fetch(:existing, :error) # Capture content = capture(&block) # Prepare for store snapshot_contents = @item.reps[:default].unwrap.snapshot_contents capture_name = "__capture_#{name}".to_sym case existing_behavior when :overwrite snapshot_contents[capture_name] = '' when :append snapshot_contents[capture_name] ||= '' when :error if snapshot_contents[capture_name] && snapshot_contents[capture_name] != content # FIXME: get proper exception raise "a capture named #{name.inspect} for #{@item.identifier} already exists" else snapshot_contents[capture_name] = '' end else raise ArgumentError, 'expected :existing_behavior param to #content_for to be one of ' \ ":overwrite, :append, or :error, but #{existing_behavior.inspect} was given" end # Store snapshot_contents[capture_name] << content else # Get content if args.size != 2 raise ArgumentError, 'expected 2 arguments (the item ' \ "and the name of the capture) but got #{args.size} instead" end item = args[0] name = args[1] rep = item.reps[:default].unwrap # Create dependency if @item.nil? || item != @item.unwrap dependency_tracker = @config._context.dependency_tracker dependency_tracker.bounce(item.unwrap) unless rep.compiled? raise Nanoc::Int::Errors::UnmetDependency.new(rep) end end rep.snapshot_contents["__capture_#{name}".to_sym] end end |