class Asciidoctor::Converter::TemplateConverter

A {Converter} implementation that uses templates composed in template languages supported by {github.com/rtomayko/tilt Tilt} to convert {AbstractNode} objects from a parsed AsciiDoc document tree to the backend format.

The converter scans the specified directories for template files that are supported by Tilt. If an engine name (e.g., “slim”) is specified in the options Hash passed to the constructor, the scan is restricted to template files that have a matching extension (e.g., “.slim”). The scanner trims any extensions from the basename of the file and uses the resulting name as the key under which to store the template. When the {Converter#convert} method is invoked, the transform argument is used to select the template from this table and use it to convert the node.

For example, the template file “path/to/templates/paragraph.html.slim” will be registered as the “paragraph” transform. The template is then used to convert a paragraph {Block} object from the parsed AsciiDoc tree to an HTML backend format (e.g., “html5”).

As an optimization, scan results and templates are cached for the lifetime of the Ruby process. If the {rubygems.org/gems/concurrent-ruby concurrent-ruby} gem is installed, these caches are guaranteed to be thread safe. If this gem is not present, there is no such guarantee and a warning will be issued.

Constants

DEFAULT_ENGINE_OPTIONS

Attributes

caches[R]

Public Class Methods

clear_caches() click to toggle source

# File lib/asciidoctor/converter/template.rb, line 46
def clear_caches
  @caches[:scans].clear
  @caches[:templates].clear
end

new(backend, template_dirs, opts = {}) click to toggle source

# File lib/asciidoctor/converter/template.rb, line 52
def initialize backend, template_dirs, opts = {}
  Helpers.require_library 'tilt' unless defined? ::Tilt.new
  @backend = backend
  @templates = {}
  @template_dirs = template_dirs
  @eruby = opts[:eruby]
  @safe = opts[:safe]
  @active_engines = {}
  @engine = opts[:template_engine]
  @engine_options = {}.tap {|accum| DEFAULT_ENGINE_OPTIONS.each {|engine, engine_opts| accum[engine] = engine_opts.merge } }
  if opts[:htmlsyntax] == 'html' # if not set, assume xml since this converter is also used for DocBook (which doesn't specify htmlsyntax)
    @engine_options[:haml][:format] = :html5
    @engine_options[:slim][:format] = :html
  end
  @engine_options[:slim][:include_dirs] = template_dirs.reverse.map {|dir| ::File.expand_path dir }
  if (overrides = opts[:template_engine_options])
    overrides.each do |engine, override_opts|
      (@engine_options[engine] ||= {}).update override_opts
    end
  end
  case opts[:template_cache]
  when true
    logger.warn 'optional gem \'concurrent-ruby\' is not available. This gem is recommended when using the default template cache.' unless defined? ::Concurrent::Map
    @caches = self.class.caches
  when ::Hash
    @caches = opts[:template_cache]
  else
    @caches = {} # the empty Hash effectively disables caching
  end
  scan
end

Public Instance Methods

convert(node, template_name = nil, opts = nil) click to toggle source

Public: Convert an {AbstractNode} to the backend format using the named template.

Looks for a template that matches the value of the template name or, if the template name is not specified, the value of the {AbstractNode#node_name} property.

node - the AbstractNode to convert template_name - the String name of the template to use, or the value of

the node_name property on the node if a template name is
not specified. (optional, default: nil)

opts - an optional Hash that is passed as local variables to the

template. (optional, default: nil)

Returns the [String] result from rendering the template

# File lib/asciidoctor/converter/template.rb, line 97
def convert node, template_name = nil, opts = nil
  unless (template = @templates[template_name ||= node.node_name])
    raise %(Could not find a custom template to handle transform: #{template_name})
  end

  # Slim doesn't include helpers in the template's execution scope (like HAML), so do it ourselves
  node.extend ::Slim::Helpers if (defined? ::Slim::Helpers) && (::Slim::Template === template)

  # NOTE opts become locals in the template
  if template_name == 'document'
    (template.render node, opts).strip
  else
    (template.render node, opts).rstrip
  end
end

handles?(name) click to toggle source

Public: Checks whether there is a Tilt template registered with the specified name.

name - the String template name

Returns a [Boolean] that indicates whether a Tilt template is registered for the specified template name.

# File lib/asciidoctor/converter/template.rb, line 119
def handles? name
  @templates.key? name
end

Public: Registers a Tilt template with this converter.

name - the String template name template - the Tilt template object to register

Returns the Tilt template object

# File lib/asciidoctor/converter/template.rb, line 136
def register name, template
  if (template_cache = @caches[:templates])
    template_cache[template.file] = template
  end
  @templates[name] = template
end

templates() click to toggle source

Public: Retrieves the templates that this converter manages.

Returns a [Hash] of Tilt template objects keyed by template name.

# File lib/asciidoctor/converter/template.rb, line 126
def templates
  @templates.merge
end