Class: Protocol::HTTP2::Stream
- Inherits:
-
Object
- Object
- Protocol::HTTP2::Stream
show all
- Includes:
- FlowControlled
- Defined in:
- lib/protocol/http2/stream.rb
Overview
A single HTTP 2.0 connection can multiplex multiple streams in parallel: multiple requests and responses can be in flight simultaneously and stream data can be interleaved and prioritized.
This class encapsulates all of the state, transition, flow-control, and error management as defined by the HTTP 2.0 specification. All you have to do is subscribe to appropriate events (marked with “:” prefix in diagram below) and provide your application logic to handle request and response processing.
+--------+
send PP | | recv PP
,--------| idle |--------.
/ | | \
v +--------+ v
+----------+ | +----------+
| | | send H / | |
,——| reserved | | recv H | reserved |——. | | (local) | | | (remote) | | | ----------
v ----------
| | | --------
| | | | recv ES | | send ES | | | send H | ,——-| open |——-. | recv H | | | / | | \ | | | v v --------
v v | | ----------
| ----------
| | | half | | | half | | | | closed | | send R / | closed | | | | (remote) | | recv R | (local) | | | ----------
| ----------
| | | | | | | | send ES / | recv ES / | | | | send R / v send R / | | | | recv R --------
recv R | | | send R / ‘———–>| |<———–’ send R / | | recv R | closed | recv R | ‘———————–>| |<———————-’
+--------+
send: endpoint sends this frame
recv: endpoint receives this frame
H: HEADERS frame (with implied CONTINUATIONs)
PP: PUSH_PROMISE frame (with implied CONTINUATIONs)
ES: END_STREAM flag
R: RST_STREAM frame
State transition methods use a trailing “!”.
Instance Attribute Summary collapse
Class Method Summary
collapse
Instance Method Summary
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#available_frame_size, #available_size, #consume_local_window, #receive_window_update, #request_window_update, #send_window_update, #update_local_window, #window_updated
Constructor Details
#initialize(connection, id, state = :idle) ⇒ Stream
Returns a new instance of Stream.
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# File 'lib/protocol/http2/stream.rb', line 85
def initialize(connection, id, state = :idle)
@connection = connection
@id = id
@state = state
@local_window = Window.new(@connection.local_settings.initial_window_size)
@remote_window = Window.new(@connection.remote_settings.initial_window_size)
@dependency = Dependency.create(@connection, @id)
end
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Instance Attribute Details
#connection ⇒ Object
The connection this stream belongs to.
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# File 'lib/protocol/http2/stream.rb', line 98
def connection
@connection
end
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#dependency ⇒ Object
Returns the value of attribute dependency.
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# File 'lib/protocol/http2/stream.rb', line 106
def dependency
@dependency
end
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#id ⇒ Object
Stream ID (odd for client initiated streams, even otherwise).
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# File 'lib/protocol/http2/stream.rb', line 101
def id
@id
end
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#local_window ⇒ Object
Returns the value of attribute local_window.
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# File 'lib/protocol/http2/stream.rb', line 108
def local_window
@local_window
end
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#remote_window ⇒ Object
Returns the value of attribute remote_window.
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# File 'lib/protocol/http2/stream.rb', line 109
def remote_window
@remote_window
end
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#state ⇒ Object
Stream state, e.g. ‘idle`, `closed`.
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# File 'lib/protocol/http2/stream.rb', line 104
def state
@state
end
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Class Method Details
.create(connection, id) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 77
def self.create(connection, id)
stream = self.new(connection, id)
connection.streams[id] = stream
return stream
end
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Instance Method Details
#accept_push_promise_stream(stream_id, headers) ⇒ Object
Override this function to implement your own push promise logic.
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# File 'lib/protocol/http2/stream.rb', line 418
def accept_push_promise_stream(stream_id, )
@connection.accept_push_promise_stream(stream_id)
end
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#active? ⇒ Boolean
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# File 'lib/protocol/http2/stream.rb', line 139
def active?
@state != :closed && @state != :idle
end
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#close(error = nil) ⇒ Object
The stream is being closed because the connection is being closed.
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# File 'lib/protocol/http2/stream.rb', line 128
def close(error = nil)
end
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#close!(error_code = nil) ⇒ Object
Transition the stream into the closed state.
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# File 'lib/protocol/http2/stream.rb', line 243
def close!(error_code = nil)
@state = :closed
@connection.delete(@id)
if error_code
error = StreamError.new("Stream closed!", error_code)
end
self.close(error)
return self
end
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#closed? ⇒ Boolean
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# File 'lib/protocol/http2/stream.rb', line 143
def closed?
@state == :closed
end
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#consume_remote_window(frame) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 196
def consume_remote_window(frame)
super
@connection.consume_remote_window(frame)
end
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#create_push_promise_stream(headers) ⇒ Object
Override this function to implement your own push promise logic.
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# File 'lib/protocol/http2/stream.rb', line 398
def create_push_promise_stream()
@connection.create_push_promise_stream
end
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#ignore_data(frame) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 321
def ignore_data(frame)
end
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#inspect ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 433
def inspect
"\#<#{self.class} id=#{@id} state=#{@state}>"
end
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#maximum_frame_size ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 131
def maximum_frame_size
@connection.available_frame_size
end
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#open! ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 231
def open!
if @state == :idle
@state = :open
else
raise ProtocolError, "Cannot open stream in state: #{@state}"
end
return self
end
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#parent=(stream) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 123
def parent=(stream)
@dependency.parent = stream.dependency
end
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#priority ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 115
def priority
@dependency.priority
end
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#priority=(priority) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 119
def priority= priority
@dependency.priority = priority
end
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#process_data(frame) ⇒ String
Returns the data that was received.
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# File 'lib/protocol/http2/stream.rb', line 317
def process_data(frame)
frame.unpack
end
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# File 'lib/protocol/http2/stream.rb', line 269
def (frame)
priority, data = frame.unpack
if priority
@dependency.process_priority(priority)
end
@connection.(data)
end
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#receive_data(frame) ⇒ Object
DATA frames are subject to flow control and can only be sent when a stream is in the “open” or “half-closed (remote)” state. The entire DATA frame payload is included in flow control, including the Pad Length and Padding fields if present. If a DATA frame is received whose stream is not in “open” or “half-closed (local)” state, the recipient MUST respond with a stream error of type STREAM_CLOSED.
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# File 'lib/protocol/http2/stream.rb', line 326
def receive_data(frame)
if @state == :open
update_local_window(frame)
if frame.end_stream?
@state = :half_closed_remote
end
process_data(frame)
elsif @state == :half_closed_local
update_local_window(frame)
process_data(frame)
if frame.end_stream?
close!
end
elsif self.closed?
ignore_data(frame)
else
self.send_reset_stream(Error::STREAM_CLOSED)
end
end
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# File 'lib/protocol/http2/stream.rb', line 284
def (frame)
if @state == :idle
if frame.end_stream?
@state = :half_closed_remote
else
open!
end
(frame)
elsif @state == :reserved_remote
(frame)
@state = :half_closed_local
elsif @state == :open
(frame)
if frame.end_stream?
@state = :half_closed_remote
end
elsif @state == :half_closed_local
(frame)
if frame.end_stream?
close!
end
elsif self.closed?
(frame)
else
self.send_reset_stream(Error::STREAM_CLOSED)
end
end
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#receive_push_promise(frame) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 422
def receive_push_promise(frame)
promised_stream_id, data = frame.unpack
= @connection.(data)
stream = self.accept_push_promise_stream(promised_stream_id, )
stream.parent = self
stream.reserved_remote!
return stream,
end
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#receive_reset_stream(frame) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 351
def receive_reset_stream(frame)
if @state == :idle
raise ProtocolError, "Cannot receive reset stream in state: #{@state}!"
else
error_code = frame.unpack
close!(error_code)
return error_code
end
end
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#reserved_local! ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 381
def reserved_local!
if @state == :idle
@state = :reserved_local
else
raise ProtocolError, "Cannot reserve stream in state: #{@state}"
end
end
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#reserved_remote! ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 389
def reserved_remote!
if @state == :idle
@state = :reserved_remote
else
raise ProtocolError, "Cannot reserve stream in state: #{@state}"
end
end
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#send_data(*arguments, **options) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 213
def send_data(*arguments, **options)
if @state == :open
frame = write_data(*arguments, **options)
if frame.end_stream?
@state = :half_closed_local
end
elsif @state == :half_closed_remote
frame = write_data(*arguments, **options)
if frame.end_stream?
close!
end
else
raise ProtocolError, "Cannot send data in state: #{@state}"
end
end
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The HEADERS frame is used to open a stream, and additionally carries a header block fragment. HEADERS frames can be sent on a stream in the “idle”, “reserved (local)”, “open”, or “half-closed (remote)” state.
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# File 'lib/protocol/http2/stream.rb', line 166
def (*arguments)
if @state == :idle
frame = (*arguments)
if frame.end_stream?
@state = :half_closed_local
else
open!
end
elsif @state == :reserved_local
frame = (*arguments)
@state = :half_closed_remote
elsif @state == :open
frame = (*arguments)
if frame.end_stream?
@state = :half_closed_local
end
elsif @state == :half_closed_remote
frame = (*arguments)
if frame.end_stream?
close!
end
else
raise ProtocolError, "Cannot send headers in state: #{@state}"
end
end
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# File 'lib/protocol/http2/stream.rb', line 147
def
@state == :idle or @state == :reserved_local or @state == :open or @state == :half_closed_remote
end
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#send_push_promise(headers) ⇒ Object
Server push is semantically equivalent to a server responding to a request; however, in this case, that request is also sent by the server, as a PUSH_PROMISE frame.
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# File 'lib/protocol/http2/stream.rb', line 404
def send_push_promise()
if @state == :open or @state == :half_closed_remote
promised_stream = self.create_push_promise_stream()
promised_stream.reserved_local!
write_push_promise(promised_stream.id, )
return promised_stream
else
raise ProtocolError, "Cannot send push promise in state: #{@state}"
end
end
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#send_reset_stream(error_code = 0) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 256
def send_reset_stream(error_code = 0)
if @state != :idle and @state != :closed
frame = ResetStreamFrame.new(@id)
frame.pack(error_code)
write_frame(frame)
close!
else
raise ProtocolError, "Cannot send reset stream (#{error_code}) in state: #{@state}"
end
end
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#to_s ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 437
def to_s
inspect
end
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#weight ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 111
def weight
@dependency.weight
end
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#write_frame(frame) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 135
def write_frame(frame)
@connection.write_frame(frame)
end
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