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using Plum::BinaryString
module Plum
class Connection
include EventEmitter
include FlowControl
include ConnectionUtils
CLIENT_CONNECTION_PREFACE = "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n"
DEFAULT_SETTINGS = {
header_table_size: 4096, # octets
enable_push: 1, # 1: enabled, 0: disabled
max_concurrent_streams: 1 << 30, # (1 << 31) / 2
initial_window_size: 65535, # octets; <= 2 ** 31 - 1
max_frame_size: 16384, # octets; <= 2 ** 24 - 1
max_header_list_size: (1 << 32) - 1 # Fixnum
}
attr_reader :hpack_encoder, :hpack_decoder
attr_reader :local_settings, :remote_settings
attr_reader :state, :streams, :io
def initialize(io, local_settings = {})
@io = io
@local_settings = Hash.new {|hash, key| DEFAULT_SETTINGS[key] }.merge!(local_settings)
@remote_settings = Hash.new {|hash, key| DEFAULT_SETTINGS[key] }
@buffer = "".force_encoding(Encoding::BINARY)
@streams = {}
@state = :negotiation
@hpack_decoder = HPACK::Decoder.new(@local_settings[:header_table_size])
@hpack_encoder = HPACK::Encoder.new(@remote_settings[:header_table_size])
initialize_flow_control(send: @remote_settings[:initial_window_size],
recv: @local_settings[:initial_window_size])
end
private :initialize
# Starts communication with the peer. It blocks until the io is closed, or reaches EOF.
def run
while !@io.closed? && !@io.eof?
receive @io.readpartial(1024)
end
end
# Closes the io.
def close
# TODO: server MAY wait streams
@io.close
end
# Receives the specified data and process.
#
# @param new_data [String] The data received from the peer.
def receive(new_data)
return if new_data.empty?
@buffer << new_data
negotiate! if @state == :negotiation
if @state != :negotiation
while frame = Frame.parse!(@buffer)
callback(:frame, frame)
receive_frame(frame)
end
end
rescue ConnectionError => e
callback(:connection_error, e)
goaway(e.http2_error_type)
close
end
alias << receive
# Reserves a new stream to server push.
#
# @param args [Hash] The argument to pass to Stram.new.
def reserve_stream(**args)
next_id = ((@streams.keys.last / 2).to_i + 1) * 2
stream = new_stream(next_id, state: :reserved_local, **args)
stream
end
private
def send_immediately(frame)
callback(:send_frame, frame)
@io.write(frame.assemble)
end
def negotiate!
unless CLIENT_CONNECTION_PREFACE.start_with?(@buffer.byteslice(0, 24))
raise ConnectionError.new(:protocol_error) # (MAY) send GOAWAY. sending.
end
if @buffer.bytesize >= 24
@buffer.byteshift(24)
@state = :waiting_settings
settings(@local_settings)
end
end
def new_stream(stream_id, **args)
if @streams.size > 0 && @streams.keys.max >= stream_id
raise Plum::ConnectionError.new(:protocol_error)
end
stream = Stream.new(self, stream_id, **args)
callback(:stream, stream)
@streams[stream_id] = stream
stream
end
def validate_received_frame(frame)
if @state == :waiting_settings && frame.type != :settings
raise ConnectionError.new(:protocol_error)
end
if @state == :waiting_continuation
if frame.type != :continuation || frame.stream_id != @continuation_id
raise ConnectionError.new(:protocol_error)
end
if frame.flags.include?(:end_headers)
@state = :open
@continuation_id = nil
end
end
if [:headers].include?(frame.type)
if !frame.flags.include?(:end_headers)
@state = :waiting_continuation
@continuation_id = frame.stream_id
end
end
end
def receive_frame(frame)
validate_received_frame(frame)
consume_recv_window(frame)
if frame.stream_id == 0
receive_control_frame(frame)
else
if @streams.key?(frame.stream_id)
stream = @streams[frame.stream_id]
else
raise ConnectionError.new(:protocol_error) if frame.stream_id.even? # stream started by client must have odd ID
stream = new_stream(frame.stream_id)
end
stream.receive_frame(frame)
end
end
def receive_control_frame(frame)
if frame.length > @local_settings[:max_frame_size]
raise ConnectionError.new(:frame_size_error)
end
case frame.type
when :settings
receive_settings(frame)
when :window_update
receive_window_update(frame)
when :ping
receive_ping(frame)
when :goaway
goaway
close
when :data, :headers, :priority, :rst_stream, :push_promise, :continuation
raise Plum::ConnectionError.new(:protocol_error)
else
# MUST ignore unknown frame type.
end
end
def receive_settings(frame, send_ack: true)
if frame.flags.include?(:ack)
raise ConnectionError.new(:frame_size_error) if frame.length != 0
callback(:settings_ack)
return
else
raise ConnectionError.new(:frame_size_error) if frame.length % 6 != 0
end
old_remote_settings = @remote_settings.dup
@remote_settings.merge!(frame.parse_settings)
apply_remote_settings(old_remote_settings)
callback(:remote_settings, @remote_settings, old_remote_settings)
send_immediately Frame.settings(:ack) if send_ack
if @state == :waiting_settings
@state = :open
callback(:negotiated)
end
end
def apply_remote_settings(old_remote_settings)
@hpack_encoder.limit = @remote_settings[:header_table_size]
update_send_initial_window_size(@remote_settings[:initial_window_size] - old_remote_settings[:initial_window_size])
end
def receive_ping(frame)
raise Plum::ConnectionError.new(:frame_size_error) if frame.length != 8
if frame.flags.include?(:ack)
callback(:ping_ack)
else
opaque_data = frame.payload
callback(:ping, opaque_data)
send_immediately Frame.ping(:ack, opaque_data)
end
end
end
end
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