WIP

lib/protocol/http2/connection.rb

@@ -400,6 +400,18 @@ def receive_push_promise(frame)
 				raise ProtocolError, "Unable to receive push promise!"
 			end
 
+			def receive_priority_update(frame)
+				if frame.stream_id != 0
+					raise ProtocolError, "Invalid stream id: #{frame.stream_id}"
+				end
+
+				stream_id, value = frame.unpack
+
+				if stream = @streams[stream_id]
+					stream.priority = Protocol::HTTP::Header::Priority.new(value)
+				end
+			end
+
 			def client_stream_id?(id)
 				id.odd?
 			end

lib/protocol/http2/framer.rb

@@ -14,6 +14,7 @@
 require_relative "goaway_frame"
 require_relative "window_update_frame"
 require_relative "continuation_frame"
+require_relative "priority_update_frame"
 
 module Protocol
 	module HTTP2
@@ -29,6 +30,7 @@ module HTTP2
 			GoawayFrame,
 			WindowUpdateFrame,
 			ContinuationFrame,
+			PriorityUpdateFrame,
 		].freeze
 
 		# Default connection "fast-fail" preamble string as defined by the spec.

lib/protocol/http2/priority_update_frame.rb

@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+# Released under the MIT License.
+# Copyright, 2019-2024, by Samuel Williams.
+
+require_relative "frame"
+require_relative "padded"
+require_relative "continuation_frame"
+
+module Protocol
+	module HTTP2
+		# The PRIORITY_UPDATE frame is used by clients to signal the initial priority of a response, or to reprioritize a response or push stream. It carries the stream ID of the response and the priority in ASCII text, using the same representation as the Priority header field value.
+		# 
+		# +-+-------------+-----------------------------------------------+
+		# |R|                 Prioritized Stream ID (31)                  |
+		# +-+-----------------------------+-------------------------------+
+		# |                    Priority Field Value (*)                 ...
+		# +---------------------------------------------------------------+
+		#
+		class PriorityUpdateFrame < Frame
+			TYPE = 0x10
+			FORMAT = "N".freeze
+
+			def unpack
+				data = super
+
+				prioritized_stream_id = data.unpack(FORMAT)
+
+				return prioritized_stream_id, data.byteslice(4, data.bytesize - 4)
+			end
+
+			def pack(prioritized_stream_id, data, **options)
+				super([prioritized_stream_id].pack(FORMAT) + data, **options)
+			end
+
+			def apply(connection)
+				connection.receive_priority_update(self)
+			end
+		end
+	end
+end

lib/protocol/http2/stream.rb

@@ -76,6 +76,8 @@ def initialize(connection, id, state = :idle)
 
 				@local_window = Window.new(@connection.local_settings.initial_window_size)
 				@remote_window = Window.new(@connection.remote_settings.initial_window_size)
+
+				@priority = nil
 			end
 
 			# The connection this stream belongs to.
@@ -90,6 +92,8 @@ def initialize(connection, id, state = :idle)
 			attr :local_window
 			attr :remote_window
 
+			attr_accessor :priority
+
 			def maximum_frame_size
 				@connection.available_frame_size
 			end