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module Plum
class Stream
attr_reader :id, :state, :priority
attr_accessor :on_headers, :on_data, :on_close, :on_open, :on_complete
def initialize(con, id)
@connection = con
@id = id
@state = :idle
@continuation = false
@header_fragment = nil
end
def on_frame(frame)
case frame.type
when :data
process_data(frame)
when :headers
process_headers(frame)
when :priority
process_priority(frame)
when :rst_stream
process_rst_stream(frame)
when :push_promise
process_push_promise(frame)
when :window_update
process_window_update(frame)
when :continuation
process_continuation(frame)
when :settings
raise Plum::ConnectionError.new(:protocol_error) # stream_id MUST be 0x00
end
if frame.flags.include?(:end_stream)
on(:complete)
@state = :half_closed
end
rescue Plum::StreamError => e
on(:stream_error, e)
send Frame.new(type: :rst_stream,
stream_id: id,
payload: [e.http2_error_code].pack("N"))
close
end
def send(frame)
@connection.send(frame)
end
def send_headers(headers, flags = [])
encoded = @connection.hpack_encoder.encode(headers)
send Frame.new(type: :headers,
flags: [:end_headers] + flags,
stream_id: id,
payload: encoded)
end
def send_body(body, flags = [])
send Frame.new(type: :data,
flags: flags,
stream_id: id,
payload: body)
end
def close
@state = :closed
end
def on(name, *args)
cb = instance_variable_get("@on_#{name}")
cb.call(*args) if cb
end
private
def process_data(frame)
if @state != :open && @state != :half_closed_local
raise Plum::StreamError.new(:stream_closed)
end
body = extract_padded(frame)
on(:data, body)
end
def process_headers(frame)
on(:open)
@state = :open
payload = extract_padded(frame)
if frame.flags.include?(:priority)
process_priority_payload(payload.slice!(0, 5))
end
if frame.flags.include?(:end_headers)
on(:headers, @connection.hpack_decoder.decode(payload).to_h)
else
@header_fragment = payload
@continuation = true
end
end
def process_priority(frame)
if frame.length != 5
raise Plum::StreamError.new(:frame_size_error)
end
process_priority_payload(frame.payload)
end
def process_priority_payload(payload)
esd = payload.slice(0, 4).unpack("N")[0]
e = esd >> 31
dependency_id = e & ~(1 << 31)
weight = payload.slice(4, 1).unpack("C")[0]
end
def process_rst_stream(frame)
if @state == :idle
raise Plum::ConnectionError.new(:protocol_error)
elsif frame.length != 4
raise Plum::ConnectionError.new(:frame_size_error)
else
close
end
end
def process_push_promise(frame)
payload = extract_padded(frame)
rpsid = payload.slice!(0, 4).unpack("N")[0]
r = rpsid >> 31
psid = rpsid & ~(1 << 31)
# TODO
end
def process_window_update(frame)
if frame.size != 4
raise Plum::ConnectionError.new(:frame_size_error)
end
inc = frame.payload.unpack("N")[0]
if inc == 0
raise Plum::StreamError.new(:protocol_error)
end
# TODO
end
def process_continuation(frame)
# TODO
unless @continuation
raise Plum::ConnectionError.new(:protocol_error)
end
@header_fragment << frame.payload
if frame.flags.include?(:end_headers)
if @continuation == :push_promise
@connection.push_promise
else # @continuation == :headers
headers = @connection.hpack_decoder.decode(@header_fragment)
end
@header_fragment = nil
@continuation = nil
else
# continue
end
end
def extract_padded(frame)
if frame.flags.include?(:padded)
padding_length = frame.payload[0, 1].unpack("C")[0]
if padding_length > frame.length
raise Plum::ConnectionError.new(:protocol_error, "padding is too long")
end
frame.payload[1, frame.length - padding_length - 1]
else
frame.payload
end
end
end
end
|
