Class: Protocol::HTTP2::Stream
- Inherits:
-
Object
- Object
- Protocol::HTTP2::Stream
show all
- Includes:
- FlowControl
- 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
Instance Attribute Summary collapse
Instance Method Summary
collapse
#available_frame_size, #consume_local_window, #receive_window_update, #send_window_update, #window_updated
Constructor Details
#initialize(connection, id = connection.next_stream_id) ⇒ Stream
Returns a new instance of Stream.
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# File 'lib/protocol/http2/stream.rb', line 76
def initialize(connection, id = connection.next_stream_id)
@connection = connection
@id = id
@connection.streams[@id] = self
@state = :idle
@priority = nil
@local_window = Window.new(connection.local_settings.initial_window_size)
@remote_window = Window.new(connection.remote_settings.initial_window_size)
@headers = nil
@data = nil
end
|
Instance Attribute Details
#data ⇒ Object
Returns the value of attribute data.
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# File 'lib/protocol/http2/stream.rb', line 99
def data
@data
end
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Returns the value of attribute headers.
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# File 'lib/protocol/http2/stream.rb', line 98
def
@headers
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 93
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 101
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 102
def remote_window
@remote_window
end
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#state ⇒ Object
Stream state as defined by HTTP 2.0.
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# File 'lib/protocol/http2/stream.rb', line 96
def state
@state
end
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Instance Method Details
#close!(state = :closed) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 211
def close!(state = :closed)
@state = state
@connection.streams.delete(@id)
end
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#closed? ⇒ Boolean
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# File 'lib/protocol/http2/stream.rb', line 112
def closed?
@state == :closed or @state == :reset
end
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#consume_remote_window(frame) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 175
def consume_remote_window(frame)
super
@connection.consume_remote_window(frame)
end
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#create_promise_stream(headers, stream_id) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 342
def create_promise_stream(, stream_id)
@connection.create_stream(stream_id)
end
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#maximum_frame_size ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 104
def maximum_frame_size
@connection.available_frame_size
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 274
def receive_data(frame)
if @state == :open
consume_local_window(frame)
if frame.end_stream?
@state = :half_closed_remote
end
@data = frame.unpack
elsif @state == :half_closed_local
consume_local_window(frame)
if frame.end_stream?
close!
end
@data = frame.unpack
elsif @state == :reset
else
raise ProtocolError, "Cannot receive data in state: #{@state}"
end
end
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# File 'lib/protocol/http2/stream.rb', line 241
def (frame)
if @state == :idle
if frame.end_stream?
@state = :half_closed_remote
else
@state = :open
end
@headers = (frame)
elsif @state == :reserved_remote
@state = :half_closed_local
@headers = (frame)
elsif @state == :open
if frame.end_stream?
@state = :half_closed_remote
end
@headers = (frame)
elsif @state == :half_closed_local
if frame.end_stream?
close!
end
@headers = (frame)
elsif @state == :reset
else
raise ProtocolError, "Cannot receive headers in state: #{@state}"
end
end
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#receive_priority(frame) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 298
def receive_priority(frame)
@priority = frame.unpack
end
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#receive_push_promise(frame) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 361
def receive_push_promise(frame)
promised_stream_id, data = frame.unpack
= @connection.(data)
stream = self.create_promise_stream(, promised_stream_id)
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 302
def receive_reset_stream(frame)
if @state != :idle and @state != :closed
close!
return frame.unpack
else
raise ProtocolError, "Cannot reset stream in state: #{@state}"
end
end
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#reserved_local! ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 326
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 334
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(*args) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 193
def send_data(*args)
if @state == :open
frame = write_data(*args)
if frame.end_stream?
@state = :half_closed_local
end
elsif @state == :half_closed_remote
frame = write_data(*args)
if frame.end_stream?
close!
end
else
raise ProtocolError, "Cannot send data in state: #{@state}"
end
end
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#send_failure(status, reason) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 120
def send_failure(status, reason)
if
(nil, [
[':status', status.to_s],
['reason', reason]
], END_STREAM)
else
send_reset_stream(PROTOCOL_ERROR)
end
return nil
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 145
def (*args)
if @state == :idle
frame = (*args)
if frame.end_stream?
@state = :half_closed_local
else
@state = :open
end
elsif @state == :reserved_local
frame = (*args)
@state = :half_closed_remote
elsif @state == :open
frame = (*args)
if frame.end_stream?
@state = :half_closed_local
end
elsif @state == :half_closed_remote
frame = (*args)
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 116
def
@state == :idle or @state == :reserved_local or @state == :open or @state == :half_closed_remote
end
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#send_push_promise(headers, stream_id = @connection.next_stream_id) ⇒ 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 348
def send_push_promise(, stream_id = @connection.next_stream_id)
if @state == :open or @state == :half_closed_remote
promised_stream = self.create_promise_stream(, stream_id)
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 217
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!(:reset)
else
raise ProtocolError, "Cannot reset stream in state: #{@state}"
end
end
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#write_frame(frame) ⇒ Object
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# File 'lib/protocol/http2/stream.rb', line 108
def write_frame(frame)
@connection.write_frame(frame)
end
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