conneg.rb in rack-linkeddata-3.1.1

- old
+ new

@@ -4,11 +4,11 @@
   #
   # Uses HTTP Content Negotiation to find an appropriate RDF
   # format to serialize any result with a body being `RDF::Enumerable`.
   #
   # Override content negotiation by setting the :format option to
-  # {#initialize}.
+  # `#initialize`.
   #
   # Add a :default option to set a content type to use when nothing else
   # is found.
   #
   # @example
@@ -16,224 +16,8 @@
   #     use Rack::LinkedData::ContentNegotiation, :format => RDF::NTriples::Format
   #     use Rack::LinkedData::ContentNegotiation, :default => 'application/rdf+xml'
   #
   # @see http://www4.wiwiss.fu-berlin.de/bizer/pub/LinkedDataTutorial/
   # @see https://www.rubydoc.info/github/rack/rack/master/file/SPEC
-  class ContentNegotiation
-    DEFAULT_CONTENT_TYPE = "application/n-triples" # N-Triples
-    VARY = {'Vary' => 'Accept'}.freeze
-
-    # @return [#call]
-    attr_reader :app
-
-    # @return [Hash{Symbol => Object}]
-    attr_reader :options
-
-    ##
-    # @param  [#call]                  app
-    # @param  [Hash{Symbol => Object}] options
-    #   Other options passed to writer.
-    # @param [String] :default (DEFAULT_CONTENT_TYPE) Specific content type
-    # @option options [RDF::Format, #to_sym] :format Specific RDF writer format to use
-    def initialize(app, options)
-      @app, @options = app, options
-      @options[:default] = (@options[:default] || DEFAULT_CONTENT_TYPE).to_s
-    end
-
-    ##
-    # Handles a Rack protocol request.
-    # Parses Accept header to find appropriate mime-type and sets content_type accordingly.
-    #
-    # Inserts ordered content types into the environment as `ORDERED_CONTENT_TYPES` if an Accept header is present
-    #
-    # @param  [Hash{String => String}] env
-    # @return [Array(Integer, Hash, #each)] Status, Headers and Body
-    # @see    http://rack.rubyforge.org/doc/SPEC.html
-    def call(env)
-      env['ORDERED_CONTENT_TYPES'] = parse_accept_header(env['HTTP_ACCEPT']) if env.has_key?('HTTP_ACCEPT')
-      response = app.call(env)
-      body = response[2].respond_to?(:body) ? response[2].body : response[2]
-      case body
-        when RDF::Enumerable
-          response[2] = body  # Put it back in the response, it might have been a proxy
-          serialize(env, *response)
-        else response
-      end
-    end
-
-    ##
-    # Serializes an `RDF::Enumerable` response into a Rack protocol
-    # response using HTTP content negotiation rules or a specified Content-Type.
-    #
-    # Passes parameters from Accept header, and Link header to writer.
-    #
-    # @param  [Hash{String => String}] env
-    # @param  [Integer]                status
-    # @param  [Hash{String => Object}] headers
-    # @param  [RDF::Enumerable]        body
-    # @return [Array(Integer, Hash, #each)] Status, Headers and Body
-    def serialize(env, status, headers, body)
-      result, content_type = nil, nil
-      find_writer(env, headers) do |writer, ct, accept_params = {}|
-        begin
-          # Passes content_type as writer option to allow parameters to be extracted.
-          writer_options = @options.merge(
-            accept_params: accept_params,
-            link: env['HTTP_LINK']
-          )
-          result, content_type = writer.dump(body, nil, **writer_options), ct.split(';').first
-          break
-        rescue RDF::WriterError
-          # Continue to next writer
-          ct
-        rescue
-          ct
-        end
-      end
-
-      if result
-        headers = headers.merge(VARY).merge('Content-Type' => content_type)
-        [status, headers, [result]]
-      else
-        not_acceptable
-      end
-    end
-
-    protected
-    ##
-    # Yields an `RDF::Writer` class for the given `env`.
-    #
-    # If options contain a `:format` key, it identifies the specific format to use;
-    # otherwise, if the environment has an HTTP_ACCEPT header, use it to find a writer;
-    # otherwise, use the default content type
-    #
-    # @param  [Hash{String => String}] env
-    # @param  [Hash{String => Object}] headers
-    # @yield |writer, content_type|
-    # @yield_param [RDF::Writer] writer
-    # @yield_param [String] content_type from accept media-range without parameters
-    # @yield_param [Hash{Symbol => String}] accept_params from accept media-range
-    # @see    http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
-    def find_writer(env, headers)
-      if @options[:format]
-        format = @options[:format]
-        writer = RDF::Writer.for(format.to_sym)
-        yield(writer, writer.format.content_type.first) if writer
-      elsif env.has_key?('HTTP_ACCEPT')
-        content_types = parse_accept_header(env['HTTP_ACCEPT'])
-        content_types.each do |content_type|
-          find_writer_for_content_type(content_type) do |writer, ct, accept_params|
-            # Yields content type with parameters
-            yield(writer, ct, accept_params)
-          end
-        end
-      else
-        # HTTP/1.1 §14.1: "If no Accept header field is present, then it is
-        # assumed that the client accepts all media types"
-        find_writer_for_content_type(options[:default]) do |writer, ct|
-          # Yields content type with parameters
-          yield(writer, ct)
-        end
-      end
-    end
-
-    ##
-    # Yields an `RDF::Writer` class for the given `content_type`.
-    #
-    # Calls `Writer#accept?(content_type)` for matched content type to allow writers to further discriminate on how if to accept content-type with specified parameters.
-    #
-    # @param  [String, #to_s] content_type
-    # @yield |writer, content_type|
-    # @yield_param [RDF::Writer] writer
-    # @yield_param [String] content_type (including media-type parameters)
-    def find_writer_for_content_type(content_type)
-      ct, *params = content_type.split(';').map(&:strip)
-      accept_params = params.inject({}) do |memo, pv|
-        p, v = pv.split('=').map(&:strip)
-        memo.merge(p.downcase.to_sym => v.sub(/^["']?([^"']*)["']?$/, '\1'))
-      end
-      formats = RDF::Format.each(content_type: ct, has_writer: true).to_a.reverse
-      formats.each do |format|
-        yield format.writer, (ct || format.content_type.first), accept_params if
-          format.writer.accept?(accept_params)
-      end
-    end
-
-    ##
-    # Parses an HTTP `Accept` header, returning an array of MIME content
-    # types ordered by the precedence rules defined in HTTP/1.1 §14.1.
-    #
-    # @param  [String, #to_s] header
-    # @return [Array<String>]
-    # @see    http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.1
-    def parse_accept_header(header)
-      entries = header.to_s.split(',')
-      entries = entries.map { |e| accept_entry(e) }.sort_by(&:last).map(&:first)
-      entries.map { |e| find_content_type_for_media_range(e) }.flatten
-    end
-
-    # Returns pair of content_type (including non-'q' parameters)
-    # and array of quality, number of '*' in content-type, and number of non-'q' parameters
-    def accept_entry(entry)
-      type, *options = entry.split(';').map(&:strip)
-      quality = 0 # we sort smallest first
-      options.delete_if { |e| quality = 1 - e[2..-1].to_f if e.start_with? 'q=' }
-      [options.unshift(type).join(';'), [quality, type.count('*'), 1 - options.size]]
-    end
-
-    ##
-    # Returns a content type appropriate for the given `media_range`,
-    # returns `nil` if `media_range` contains a wildcard subtype
-    # that is not mapped.
-    #
-    # @param  [String, #to_s] media_range
-    # @return [String, nil]
-    def find_content_type_for_media_range(media_range)
-      case media_range.to_s
-      when '*/*'
-        options[:default]
-      when 'text/*'
-        'text/turtle'
-      when 'application/*'
-        'application/ld+json'
-      when 'application/json'
-        'application/ld+json'
-      when 'application/xml'
-        'application/rdf+xml'
-      when /^([^\/]+)\/\*$/
-        nil
-      else
-        media_range.to_s
-      end
-    end
-
-    ##
-    # Outputs an HTTP `406 Not Acceptable` response.
-    #
-    # @param  [String, #to_s] message
-    # @return [Array(Integer, Hash, #each)]
-    def not_acceptable(message = nil)
-      http_error(406, message, VARY)
-    end
-
-    ##
-    # Outputs an HTTP `4xx` or `5xx` response.
-    #
-    # @param  [Integer, #to_i]         code
-    # @param  [String, #to_s]          message
-    # @param  [Hash{String => String}] headers
-    # @return [Array(Integer, Hash, #each)]
-    def http_error(code, message = nil, headers = {})
-      message = http_status(code) + (message.nil? ? "\n" : " (#{message})\n")
-      [code, {'Content-Type' => "text/plain"}.merge(headers), [message]]
-    end
-
-    ##
-    # Returns the standard HTTP status message for the given status `code`.
-    #
-    # @param  [Integer, #to_i] code
-    # @return [String]
-    def http_status(code)
-      [code, Rack::Utils::HTTP_STATUS_CODES[code]].join(' ')
-    end
+  class ContentNegotiation < Rack::RDF::ContentNegotiation
   end # class ContentNegotiation
 end; end # module Rack::LinkedData