Add support for accept header.

Author: ioquatix

lib/protocol/http/header/accept.rb

@@ -0,0 +1,129 @@
+# frozen_string_literal: true
+
+# Released under the MIT License.
+# Copyright, 2020-2023, by Samuel Williams.
+# Copyright, 2023, by Thomas Morgan.
+
+require_relative "split"
+require_relative "quoted_string"
+require_relative "../error"
+
+module Protocol
+	module HTTP
+		module Header
+			# The `accept-content-type` header represents a list of content-types that the client can accept.
+			class Accept < Array
+				# Regular expression used to split values on commas, with optional surrounding whitespace, taking into account quoted strings.
+				SPLIT = /
+					(?:            # Start non-capturing group
+						"[^"\\]*"    # Match quoted strings (no escaping of quotes within)
+						|            # OR
+						[^,"]+       # Match non-quoted strings until a comma or quote
+					)+
+					(?=,|\z)       # Match until a comma or end of string
+				/x
+				
+				ParseError = Class.new(Error)
+				
+				MEDIA_RANGE = /\A(?<type>#{TOKEN})\/(?<subtype>#{TOKEN})(?<parameters>.*)\z/
+				
+				PARAMETER = /\s*;\s*(?<key>#{TOKEN})=((?<value>#{TOKEN})|(?<quoted_value>#{QUOTED_STRING}))/
+				
+				# A single entry in the Accept: header, which includes a mime type and associated parameters.
+				MediaRange = Struct.new(:type, :subtype, :parameters) do
+					def initialize(type, subtype = '*', parameters = {})
+						super(type, subtype, parameters)
+					end
+					
+					def <=> other
+						other.quality_factor <=> self.quality_factor
+					end
+					
+					def parameters_string
+						return '' if parameters == nil or parameters.empty?
+						
+						parameters.collect do |key, value|
+							"; #{key.to_s}=#{QuotedString.quote(value.to_s)}"
+						end.join
+					end
+					
+					def === other
+						if other.is_a? self.class
+							super
+						else
+							return self.mime_type === other
+						end
+					end
+					
+					def mime_type
+						"#{type}/#{subtype}"
+					end
+					
+					def to_s
+						"#{type}/#{subtype}#{parameters_string}"
+					end
+					
+					alias to_str to_s
+					
+					def quality_factor
+						parameters.fetch('q', 1.0).to_f
+					end
+					
+					def split(*args)
+						return [type, subtype]
+					end
+				end
+				
+				def initialize(value = nil)
+					if value
+						super(value.scan(SPLIT).map(&:strip))
+					else
+					end
+				end
+				
+				# Adds one or more comma-separated values to the header.
+				#
+				# The input string is split into distinct entries and appended to the array.
+				#
+				# @parameter value [String] the value or values to add, separated by commas.
+				def << (value)
+					self.concat(value.scan(SPLIT).map(&:strip))
+				end
+				
+				# Serializes the stored values into a comma-separated string.
+				#
+				# @returns [String] the serialized representation of the header values.
+				def to_s
+					join(",")
+				end
+				
+				# Parse the `accept` header.
+				#
+				# @returns [Array(Charset)] the list of content types and their associated parameters.
+				def media_ranges
+					self.map do |value|
+						self.parse_media_range(value)
+					end
+				end
+				
+				private
+				
+				def parse_media_range(value)
+					if match = value.match(MEDIA_RANGE)
+						type = match[:type]
+						subtype = match[:subtype]
+						parameters = {}
+						
+						match[:parameters].scan(PARAMETER) do |key, value, quoted_value|
+							parameters[key] = quoted_value || value
+						end
+						
+						return MediaRange.new(type, subtype, parameters)
+					else
+						raise ArgumentError, "Invalid media type: #{value.inspect}"
+					end
+				end
+			end
+		end
+	end
+end

lib/protocol/http/header/split.rb

@@ -30,7 +30,7 @@ def initialize(value = nil)
 				#
 				# @parameter value [String] the value or values to add, separated by commas.
 				def << value
-					self.push(*value.split(COMMA))
+					self.concat(value.split(COMMA))
 				end
 
 				# Serializes the stored values into a comma-separated string.

lib/protocol/http/headers.rb

@@ -3,11 +3,9 @@
 # Released under the MIT License.
 # Copyright, 2018-2024, by Samuel Williams.
 
-require_relative "header/accept_charset"
-require_relative "header/accept_encoding"
-require_relative "header/accept_language"
 require_relative "header/split"
 require_relative "header/multiple"
+
 require_relative "header/cookie"
 require_relative "header/connection"
 require_relative "header/cache_control"
@@ -18,6 +16,11 @@
 require_relative "header/date"
 require_relative "header/priority"
 
+require_relative "header/accept"
+require_relative "header/accept_charset"
+require_relative "header/accept_encoding"
+require_relative "header/accept_language"
+
 module Protocol
 	module HTTP
 		# @namespace
@@ -281,6 +284,8 @@ def []= key, value
 				"if-modified-since" => Header::Date,
 				"if-unmodified-since" => Header::Date,
 
+				# Accept headers:
+				"accept" => Header::Accept,
 				"accept-charset" => Header::AcceptCharset,
 				"accept-encoding" => Header::AcceptEncoding,
 				"accept-language" => Header::AcceptLanguage,

test/protocol/http/header/accept.rb

@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+# Released under the MIT License.
+# Copyright, 2016, by Matthew Kerwin.
+# Copyright, 2017-2024, by Samuel Williams.
+
+require 'protocol/http/header/accept'
+	
+describe Protocol::HTTP::Header::Accept::MediaRange do
+	it "should have default quality_factor of 1.0" do
+		language = subject.new('text/plain', nil)
+		expect(language.quality_factor).to be == 1.0
+	end
+end
+
+describe Protocol::HTTP::Header::Accept do
+	let(:header) {subject.new(description)}
+	let(:media_ranges) {header.media_ranges.sort}
+	
+	with "text/plain, text/html;q=0.5, text/xml;q=0.25" do
+		it "can parse media ranges" do
+			expect(header.length).to be == 3
+			
+			expect(media_ranges[0].mime_type).to be == "text/plain"
+			expect(media_ranges[0].quality_factor).to be == 1.0
+			
+			expect(media_ranges[1].mime_type).to be == "text/html"
+			expect(media_ranges[1].quality_factor).to be == 0.5
+			
+			expect(media_ranges[2].mime_type).to be == "text/xml"
+			expect(media_ranges[2].quality_factor).to be == 0.25
+		end
+	end
+	
+	with "text/html;q=0.25, text/xml;q=0.5, text/plain" do
+		it "should order based on quality factor" do
+			expect(media_ranges.collect(&:mime_type)).to be == %w{text/plain text/xml text/html}
+		end
+	end
+	
+	with "text/html, text/plain;q=0.8, text/xml;q=0.6, application/json" do
+		it "should order based on quality factor" do
+			expect(media_ranges.collect(&:mime_type)).to be == %w{text/html application/json text/plain text/xml}
+		end
+	end
+	
+	with "*/*;q=0" do
+		it "should accept wildcard media range" do
+			expect(media_ranges[0].mime_type).to be == "*/*"
+			expect(media_ranges[0].quality_factor).to be == 0
+		end
+	end
+	
+	
+end