Class: HTTP2::Stream

Inherits:
Object
  • Object
show all
Includes:
Emitter, Error, FlowBuffer
Defined in:
lib/http/2/stream.rb,
sig/stream.rbs

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.

                    +--------+
               PP   |        |   PP
           ,--------|  idle  |--------.
          /         |        |         \
         v          +--------+          v
  +----------+          |           +----------+
  |          |          | H         |          |
,---|:reserved |          |           |:reserved |---.
|   | (local)  |          v           | (remote) |   |
|   +----------+      +--------+      +----------+   |
|      | :active      |        |      :active |      |
|      |      ,-------|:active |-------.      |      |
|      | H   /   ES   |        |   ES   \   H |      |
|      v    v         +--------+         v    v      |
|   +-----------+          |          +-----------+  |
|   |:half_close|          |          |:half_close|  |
|   |  (remote) |          |          |  (local)  |  |
|   +-----------+          |          +-----------+  |
|        |                 v                |        |
|        |    ES/R    +--------+    ES/R    |        |
|        `----------->|        |<-----------'        |
| R                   | :close |                   R |
`-------------------->|        |<--------------------'
                    +--------+

Constant Summary collapse

STREAM_OPEN_STATES =

Returns:

  • (Array[Symbol]) 
%i[open half_closed_local half_closing closing].freeze

Constants included from FlowBuffer

FlowBuffer::MAX_WINDOW_SIZE

Instance Attribute Summary collapse

Attributes included from FlowBuffer

#send_buffer

Instance Method Summary collapse

Methods included from Error

#self?.types

Methods included from Emitter

#emit, #on, #once

Methods included from FlowBuffer

#buffered_amount, #calculate_window_update, #flush, #process_window_update, #send_data, #send_frame, #update_local_window

Constructor Details

#initialize(connection:, id:, weight: 16, dependency: 0, exclusive: false, parent: nil, state: :idle) ⇒ Stream

Initializes new stream.

Note that you should never have to call this directly. To create a new client initiated stream, use Connection#new_stream. Similarly, Connection will emit new stream objects, when new stream frames are received.

Parameters:

  • id (Integer)
  • weight (Integer) (defaults to: 16)
  • dependency (Integer) (defaults to: 0)
  • exclusive (Boolean) (defaults to: false)
  • window (Integer)
  • parent (Stream) (defaults to: nil)
  • state (Symbol) (defaults to: :idle) 


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# File 'lib/http/2/stream.rb', line 78

def initialize(connection:, id:, weight: 16, dependency: 0, exclusive: false, parent: nil, state: :idle)
  stream_error(:protocol_error, msg: "stream can't depend on itself") if id == dependency

  @connection = connection
  @id = id
  @weight = weight
  @dependency = dependency

  # from mixins
  @listeners = Hash.new { |hash, key| hash[key] = [] }
  @send_buffer = FrameBuffer.new

  process_priority(weight: weight, dependency: dependency, exclusive: exclusive)
  @local_window_max_size = connection.local_settings[:settings_initial_window_size]
  @local_window = connection.local_settings[:settings_initial_window_size]
  @remote_window = connection.remote_settings[:settings_initial_window_size]
  @parent = parent
  @state  = state
  @error  = false
  @closed = false
  @_method = @_content_length = @_status_code = @_trailers = nil
  @_waiting_on_trailers = false
  @received_data = false
  @activated = false

  on(:window) { |v| @remote_window = v }
  on(:local_window) { |v| @local_window_max_size = @local_window = v }
end

Instance Attribute Details

#closed ⇒ Symbol? (readonly)

Reason why connection was closed.

Returns:

  • (Symbol, nil) 


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# File 'lib/http/2/stream.rb', line 63

def closed
  @closed
end

#dependency ⇒ Integer (readonly)

Returns the value of attribute dependency.

Returns:

  • (Integer) 


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# File 'lib/http/2/stream.rb', line 56

def dependency
  @dependency
end

#id ⇒ Integer (readonly)

Stream ID (odd for client initiated streams, even otherwise).

Returns:

  • (Integer) 


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# File 'lib/http/2/stream.rb', line 46

def id
  @id
end

#local_window ⇒ Integer (readonly) Also known as: window

Size of current stream flow control window.

Returns:

  • (Integer) 


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# File 'lib/http/2/stream.rb', line 59

def local_window
  @local_window
end

#parent ⇒ Stream? (readonly)

Request parent stream of push stream.

Returns:



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# File 'lib/http/2/stream.rb', line 52

def parent
  @parent
end

#remote_window ⇒ Integer (readonly)

Returns the value of attribute remote_window.

Returns:

  • (Integer) 


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# File 'lib/http/2/stream.rb', line 56

def remote_window
  @remote_window
end

#state ⇒ Symbol (readonly)

Stream state as defined by HTTP 2.0.

Returns:

  • (Symbol) 


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# File 'lib/http/2/stream.rb', line 49

def state
  @state
end

#weight ⇒ Integer (readonly)

Stream priority as set by initiator.

Returns:

  • (Integer) 


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# File 'lib/http/2/stream.rb', line 55

def weight
  @weight
end

Instance Method Details

#activate_stream_in_conn ⇒ void

This method returns an undefined value.

Streams that are in the "open" state, or either of the "half closed" states count toward the maximum number of streams that an endpoint is permitted to open.



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# File 'lib/http/2/stream.rb', line 631

def activate_stream_in_conn
  @connection.active_stream_count += 1
  @activated = true
  emit(:active)
end

#calculate_content_length(data_length) ⇒ void

This method returns an undefined value.

Parameters:

  • (Integer, nil) 


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# File 'lib/http/2/stream.rb', line 189

def calculate_content_length(data_length)
  return unless @_content_length && data_length

  @_content_length -= data_length
  return if @_content_length >= 0

  stream_error(:protocol_error, msg: "received more data than what was defined in content-length")
end

#cancel ⇒ void

This method returns an undefined value.

Sends a RST_STREAM indicating that the stream is no longer needed.



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# File 'lib/http/2/stream.rb', line 293

def cancel
  send(type: :rst_stream, error: :cancel)
end

#chunk_data(payload, max_size) {|arg0| ... } ⇒ String

Chunk data into max_size, yield each chunk, then return final chunk

Parameters:

  • payload (String)
  • max_size (Integer)

Yields:

Yield Parameters:

  • arg0 (String)

Yield Returns:

  • (void)

Returns:

  • (String) 


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# File 'lib/http/2/stream.rb', line 274

def chunk_data(payload, max_size)
  total = payload.bytesize
  cursor = 0
  while (total - cursor) > max_size
    yield payload.byteslice(cursor, max_size)
    cursor += max_size
  end
  payload.byteslice(cursor, total - cursor)
end

#close(error) ⇒ void #close ⇒ void

Sends a RST_STREAM frame which closes current stream - this does not close the underlying connection.

Overloads:

  • #close(error) ⇒ void

    This method returns an undefined value.

    Parameters:

    • error (Symbol)
  • #close ⇒ void

    This method returns an undefined value.

Parameters:

  • error (:Symbol) (defaults to: :stream_closed) —

    optional reason why stream was closed



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# File 'lib/http/2/stream.rb', line 288

def close(error = :stream_closed)
  send(type: :rst_stream, error: error)
end

#close_stream_in_conn(*args) ⇒ void

This method returns an undefined value.

Parameters:

  • (Object) 


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# File 'lib/http/2/stream.rb', line 637

def close_stream_in_conn(*args)
  @connection.active_stream_count -= 1 if @activated
  emit(:close, *args)
end

#closed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/http/2/stream.rb', line 107

def closed?
  @state == :closed
end

#complete_transition(frame) ⇒ void

This method returns an undefined value.

Parameters:

  • (frame) 


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# File 'lib/http/2/stream.rb', line 642

def complete_transition(frame)
  case @state
  when :closing
    @state = :closed
    close_stream_in_conn(frame[:error])
  when :half_closing
    @state = @closed
    emit(:half_close)
  end
end

#data(payload, end_stream: true) ⇒ void

This method returns an undefined value.

Sends DATA frame containing response payload.

Parameters:

  • payload (String)
  • end_stream (Boolean) (defaults to: true) —

    indicates last response DATA frame

  • end_stream: (Boolean) (defaults to: true) 


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# File 'lib/http/2/stream.rb', line 256

def data(payload, end_stream: true)
  # Split data according to each frame is smaller enough
  # TODO: consider padding?
  max_size = @connection.remote_settings[:settings_max_frame_size]

  if payload.bytesize > max_size
    payload = chunk_data(payload, max_size) do |chunk|
      send(type: :data, flags: 0, payload: chunk)
    end
  end

  flags = 0
  flags |= END_STREAM if end_stream
  send(type: :data, flags: flags, payload: payload)
end

#end_stream?(frame) ⇒ Boolean

Parameters:

  • frame (stream_frame_props)

Returns:

  • (Boolean) 


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# File 'lib/http/2/stream.rb', line 669

def end_stream?(frame)
  case frame[:type]
  when :data, :headers, :continuation
    # @type var frame: data_frame | headers_frame | continuation_frame
    frame[:flags] && frame[:flags].anybits?(END_STREAM)
  else false
  end
end

#event(newstate) ⇒ void

This method returns an undefined value.

Parameters:

  • newstate (Symbol) 


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# File 'lib/http/2/stream.rb', line 605

def event(newstate)
  case newstate
  when :open
    @state = newstate
    activate_stream_in_conn

  when :reserved_local, :reserved_remote
    @state = newstate
    emit(:reserved)

  when :half_closed_local, :half_closed_remote
    @closed = newstate
    activate_stream_in_conn unless @state == :open
    @state = :half_closing

  when :local_closed, :remote_closed, :local_rst, :remote_rst
    @closed = newstate
    @state  = :closing
  end

  @state
end

#headers(headers, end_headers: true, end_stream: false) ⇒ void

This method returns an undefined value.

Sends a HEADERS frame containing HTTP response headers. All pseudo-header fields MUST appear in the header block before regular header fields.

Parameters:

  • headers (Array or Hash) —

    Array of key-value pairs or Hash

  • end_headers (Boolean) (defaults to: true) —

    indicates that no more headers will be sent

  • end_stream (Boolean) (defaults to: false) —

    indicates that no payload will be sent

  • end_headers: (Boolean) (defaults to: true)
  • end_stream: (Boolean) (defaults to: false) 


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# File 'lib/http/2/stream.rb', line 228

def headers(headers, end_headers: true, end_stream: false)
  flags = end_headers ? END_HEADERS : 0
  flags |= END_STREAM  if end_stream || @_method == "HEAD"

  send(type: :headers, flags: flags, payload: headers)
end

#manage_state(frame) { ... } ⇒ void

This method returns an undefined value.

Parameters:

  • frame (stream_frame_props)

Yields:

Yield Returns:

  • (void) 


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# File 'lib/http/2/stream.rb', line 688

def manage_state(frame)
  transition(frame, true)
  frame[:stream] ||= @id
  yield
  complete_transition(frame)
end

#process_priority(frame) ⇒ void

This method returns an undefined value.

Parameters:

  • frame (priority_frame_inner_props) 


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# File 'lib/http/2/stream.rb', line 653

def process_priority(frame)
  @weight = frame[:weight]
  @dependency = frame[:dependency]
  emit(
    :priority,
    weight: frame[:weight],
    dependency: frame[:dependency],
    exclusive: frame[:exclusive]
  )
  # TODO: implement dependency tree housekeeping
  #   Latest draft defines a fairly complex priority control.
  #   See https://tools.ietf.org/html/draft-ietf-httpbis-http2-16#section-5.3
  #   We currently have no prioritization among streams.
  #   We should add code here.
end

#promise(headers, end_headers: true) {|arg0| ... } ⇒ void

This method returns an undefined value.

Parameters:

  • headers (Enumerable[header_pair])
  • end_headers: (Boolean) (defaults to: true)

Yields:

Yield Parameters:

Yield Returns:

  • (void)

Raises:

  • (ArgumentError) 


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# File 'lib/http/2/stream.rb', line 235

def promise(headers, end_headers: true, &block)
  raise ArgumentError, "must provide callback" unless block

  flags = end_headers ? END_HEADERS : 0
  emit(:promise, self, headers, flags, &block)
end

#receive(frame) ⇒ void Also known as: <<

This method returns an undefined value.

Processes incoming HTTP 2.0 frames. The frames must be decoded upstream.

Parameters:

  • frame (Hash) 


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# File 'lib/http/2/stream.rb', line 114

def receive(frame)
  transition(frame, false)

  frame_type = frame[:type] #: Symbol
  case frame_type
  when :data
    # @type var frame: data_frame
    # 6.1. DATA
    # 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 (Section 5.4.2) of type STREAM_CLOSED.
    stream_error(:stream_closed) unless STREAM_OPEN_STATES.include?(@state) ||
                                        (@state == :closed && @closed == :local_rst)
    @received_data = true
    calculate_content_length(frame[:length])
    update_local_window(frame)
    # Emit DATA frame
    emit(:data, frame[:payload]) unless frame[:ignore]
    calculate_window_update(@local_window_max_size)
  when :headers
    # @type var frame: headers_frame
    stream_error(:stream_closed) if (@state == :closed && @closed != :local_rst) ||
                                    @state == :remote_closed
    @_method ||= frame[:method]
    @_status_code ||= frame[:status]
    @_content_length ||= frame[:content_length]
    @_trailers ||= frame[:trailer]
    if @_waiting_on_trailers ||
       (@received_data &&
           (!@_status_code || @_status_code >= 200))

      # An endpoint that receives a HEADERS frame without the END_STREAM flag set after receiving a final
      # (non-informational) status code MUST treat the corresponding request or response as malformed.
      verify_trailers(frame)
    end
    emit(:headers, frame[:payload]) unless frame[:ignore]
    @_waiting_on_trailers = !@_trailers.nil?
  when :push_promise
    emit(:promise_headers, frame[:payload]) unless frame[:ignore]
  when :continuation
    stream_error(:stream_closed) if (@state == :closed && @closed != :local_rst) || @state == :remote_closed
    stream_error(:protocol_error) if @received_data
  when :priority
    # @type var frame: priority_frame
    process_priority(frame)
  when :window_update
    # @type var frame: window_update_frame
    process_window_update(frame: frame)
  when :altsvc
    # @type var frame: origin_frame
    # 4.  The ALTSVC HTTP/2 Frame
    # An ALTSVC frame on a
    # stream other than stream 0 containing non-empty "Origin" information
    # is invalid and MUST be ignored.
    emit(frame_type, frame) if !frame[:origin] || frame[:origin].empty?
  end

  complete_transition(frame)
end

#refuse ⇒ void

This method returns an undefined value.

Sends a RST_STREAM indicating that the stream has been refused prior to performing any application processing.



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# File 'lib/http/2/stream.rb', line 299

def refuse
  send(type: :rst_stream, error: :refused_stream)
end

#reprioritize(weight: 16, dependency: 0, exclusive: false) ⇒ void

This method returns an undefined value.

Sends a PRIORITY frame with new stream priority value (can only be performed by the client).

Parameters:

  • weight (Integer) (defaults to: 16) —

    new stream weight value

  • dependency (Integer) (defaults to: 0) —

    new stream dependency stream

  • weight: (Integer) (defaults to: 16)
  • dependency: (Integer) (defaults to: 0)
  • exclusive: (Boolean) (defaults to: false) 


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# File 'lib/http/2/stream.rb', line 247

def reprioritize(weight: 16, dependency: 0, exclusive: false)
  stream_error if @id.even?
  send(type: :priority, weight: weight, dependency: dependency, exclusive: exclusive)
end

#send(frame) ⇒ void

This method returns an undefined value.

Processes outgoing HTTP 2.0 frames. Data frames may be automatically split and buffered based on maximum frame size and current stream flow control window size.

Parameters:

  • frame (Hash) 


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# File 'lib/http/2/stream.rb', line 203

def send(frame)
  case frame[:type]
  when :data
    # @type var frame: data_frame
    # stream state management is maintained in send_data
    return send_data(frame)
  when :window_update
    # @type var frame: window_update_frame
    @local_window += frame[:increment]
  when :priority
    # @type var frame: priority_frame
    process_priority(frame)
  end

  manage_state(frame) do
    emit(:frame, frame)
  end
end

#stream_error(error = :internal_error, msg: nil) ⇒ void Also known as: error

This method returns an undefined value.

Parameters:

  • error (Symbol) (defaults to: :internal_error)
  • msg: (String, nil) (defaults to: nil)

Raises:

  • () 


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# File 'lib/http/2/stream.rb', line 678

def stream_error(error = :internal_error, msg: nil)
  # if the stream already broke with an error, ignore subsequent

  @error = error
  close(error) if @state != :closed

  raise Error.types[error], msg
end

#transition(frame, sending) ⇒ void

This method returns an undefined value.

HTTP 2.0 Stream States

,-----| 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 | ---------------------->| |<----------------------' --------

Parameters:

  • frame (stream_frame_props)
  • sending (Boolean) 


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# File 'lib/http/2/stream.rb', line 347

def transition(frame, sending)
  case @state

  # All streams start in the "idle" state.  In this state, no frames
  # have been exchanged.
  # The following transitions are valid from this state:
  # *  Sending or receiving a HEADERS frame causes the stream to
  #    become "open".  The stream identifier is selected as described
  #    in Section 5.1.1.  The same HEADERS frame can also cause a
  #    stream to immediately become "half closed".
  # *  Sending a PUSH_PROMISE frame reserves an idle stream for later
  #    use.  The stream state for the reserved stream transitions to
  #    "reserved (local)".
  # *  Receiving a PUSH_PROMISE frame reserves an idle stream for
  #    later use.  The stream state for the reserved stream
  #    transitions to "reserved (remote)".
  # Receiving any frames other than HEADERS, PUSH_PROMISE or PRIORITY
  # on a stream in this state MUST be treated as a connection error
  # (Section 5.4.1) of type PROTOCOL_ERROR.

  when :idle
    if sending
      case frame[:type]
      when :push_promise then event(:reserved_local)
      when :headers
        if end_stream?(frame)
          event(:half_closed_local)
        else
          event(:open)
        end
      when :rst_stream then event(:local_rst)
      when :priority then process_priority(frame)
      else stream_error
      end
    else
      case frame[:type]
      when :push_promise then event(:reserved_remote)
      when :headers
        if end_stream?(frame)
          event(:half_closed_remote)
        else
          event(:open)
        end
      when :priority
      else stream_error(:protocol_error)
      end
    end

  # A stream in the "reserved (local)" state is one that has been
  # promised by sending a PUSH_PROMISE frame.  A PUSH_PROMISE frame
  # reserves an idle stream by associating the stream with an open
  # stream that was initiated by the remote peer (see Section 8.2).
  # In this state, only the following transitions are possible:
  # *  The endpoint can send a HEADERS frame.  This causes the stream
  #    to open in a "half closed (remote)" state.
  # *  Either endpoint can send a RST_STREAM frame to cause the stream
  #    to become "closed".  This releases the stream reservation.
  # An endpoint MUST NOT send any type of frame other than HEADERS,
  # RST_STREAM, or PRIORITY in this state.
  # A PRIORITY or WINDOW_UPDATE frame MAY be received in this state.
  # Receiving any type of frame other than RST_STREAM, PRIORITY or
  # WINDOW_UPDATE on a stream in this state MUST be treated as a
  # connection error (Section 5.4.1) of type PROTOCOL_ERROR.
  when :reserved_local
    if sending
      case frame[:type]
      when :headers     then event(:half_closed_remote)
      when :rst_stream  then event(:local_rst)
      when :priority
      else stream_error
      end
    else
      case frame[:type]
      when :rst_stream then event(:remote_rst)
      when :priority, :window_update
      else stream_error
      end
    end

  # A stream in the "reserved (remote)" state has been reserved by a
  # remote peer.
  # In this state, only the following transitions are possible:
  # *  Receiving a HEADERS frame causes the stream to transition to
  #    "half closed (local)".
  # *  Either endpoint can send a RST_STREAM frame to cause the stream
  #    to become "closed".  This releases the stream reservation.
  # An endpoint MAY send a PRIORITY frame in this state to
  # reprioritize the reserved stream.  An endpoint MUST NOT send any
  # type of frame other than RST_STREAM, WINDOW_UPDATE, or PRIORITY in
  # this state.
  # Receiving any type of frame other than HEADERS, RST_STREAM or
  # PRIORITY on a stream in this state MUST be treated as a connection
  # error (Section 5.4.1) of type PROTOCOL_ERROR.
  when :reserved_remote
    if sending
      case frame[:type]
      when :rst_stream then event(:local_rst)
      when :priority, :window_update
      else stream_error
      end
    else
      case frame[:type]
      when :headers then event(:half_closed_local)
      when :rst_stream then event(:remote_rst)
      when :priority
      else stream_error
      end
    end

  # A stream in the "open" state may be used by both peers to send
  # frames of any type.  In this state, sending peers observe
  # advertised stream level flow control limits (Section 5.2).
  # From this state either endpoint can send a frame with an
  # END_STREAM flag set, which causes the stream to transition into
  # one of the "half closed" states: an endpoint sending an END_STREAM
  # flag causes the stream state to become "half closed (local)"; an
  # endpoint receiving an END_STREAM flag causes the stream state to
  # become "half closed (remote)".
  # Either endpoint can send a RST_STREAM frame from this state,
  # causing it to transition immediately to "closed".
  when :open
    if sending
      case frame[:type]
      when :data, :headers, :continuation
        event(:half_closed_local) if end_stream?(frame)
      when :rst_stream then event(:local_rst)
      when :priority
      end
    else
      case frame[:type]
      when :data, :headers, :continuation
        event(:half_closed_remote) if end_stream?(frame)
      when :rst_stream then event(:remote_rst)
      when :priority
      end
    end

  # A stream that is in the "half closed (local)" state cannot be used
  # for sending frames.  Only WINDOW_UPDATE, PRIORITY and RST_STREAM
  # frames can be sent in this state.
  # A stream transitions from this state to "closed" when a frame that
  # contains an END_STREAM flag is received, or when either peer sends
  # a RST_STREAM frame.
  # A receiver can ignore WINDOW_UPDATE frames in this state, which
  # might arrive for a short period after a frame bearing the
  # END_STREAM flag is sent.
  # PRIORITY frames received in this state are used to reprioritize
  # streams that depend on the current stream.
  when :half_closed_local
    if sending
      case frame[:type]
      when :rst_stream
        event(:local_rst)
      when :priority, :window_update
      else
        stream_error
      end
    else
      case frame[:type]
      when :data, :headers, :continuation
        event(:remote_closed) if end_stream?(frame)
      when :rst_stream then event(:remote_rst)
      when :priority, :window_update
      end
    end

  # A stream that is "half closed (remote)" is no longer being used by
  # the peer to send frames.  In this state, an endpoint is no longer
  # obligated to maintain a receiver flow control window if it
  # performs flow control.
  # If an endpoint receives additional frames for a stream that is in
  # this state, other than WINDOW_UPDATE, PRIORITY or RST_STREAM, it
  # MUST respond with a stream error (Section 5.4.2) of type
  # STREAM_CLOSED.
  # A stream that is "half closed (remote)" can be used by the
  # endpoint to send frames of any type.  In this state, the endpoint
  # continues to observe advertised stream level flow control limits
  # (Section 5.2).
  # A stream can transition from this state to "closed" by sending a
  # frame that contains an END_STREAM flag, or when either peer sends
  # a RST_STREAM frame.
  when :half_closed_remote
    if sending
      case frame[:type]
      when :data, :headers, :continuation
        event(:local_closed) if end_stream?(frame)
      when :rst_stream then event(:local_rst)
      end
    else
      case frame[:type]
      when :rst_stream then event(:remote_rst)
      when :priority, :window_update
        # nop
      else
        stream_error(:stream_closed)
      end
    end

  # The "closed" state is the terminal state.
  # An endpoint MUST NOT send frames other than PRIORITY on a closed
  # stream.  An endpoint that receives any frame other than PRIORITY
  # after receiving a RST_STREAM MUST treat that as a stream error
  # (Section 5.4.2) of type STREAM_CLOSED.  Similarly, an endpoint
  # that receives any frames after receiving a frame with the
  # END_STREAM flag set MUST treat that as a connection error
  # (Section 5.4.1) of type STREAM_CLOSED, unless the frame is
  # permitted as described below.
  # WINDOW_UPDATE or RST_STREAM frames can be received in this state
  # for a short period after a DATA or HEADERS frame containing an
  # END_STREAM flag is sent.  Until the remote peer receives and
  # processes RST_STREAM or the frame bearing the END_STREAM flag, it
  # might send frames of these types.  Endpoints MUST ignore
  # WINDOW_UPDATE or RST_STREAM frames received in this state, though
  # endpoints MAY choose to treat frames that arrive a significant
  # time after sending END_STREAM as a connection error
  # (Section 5.4.1) of type PROTOCOL_ERROR.
  # PRIORITY frames can be sent on closed streams to prioritize
  # streams that are dependent on the closed stream.  Endpoints SHOULD
  # process PRIORITY frames, though they can be ignored if the stream
  # has been removed from the dependency tree (see Section 5.3.4).
  # If this state is reached as a result of sending a RST_STREAM
  # frame, the peer that receives the RST_STREAM might have already
  # sent - or enqueued for sending - frames on the stream that cannot
  # be withdrawn.  An endpoint MUST ignore frames that it receives on
  # closed streams after it has sent a RST_STREAM frame.  An endpoint
  # MAY choose to limit the period over which it ignores frames and
  # treat frames that arrive after this time as being in error.
  # Flow controlled frames (i.e., DATA) received after sending
  # RST_STREAM are counted toward the connection flow control window.
  # Even though these frames might be ignored, because they are sent
  # before the sender receives the RST_STREAM, the sender will
  # consider the frames to count against the flow control window.
  # An endpoint might receive a PUSH_PROMISE frame after it sends
  # RST_STREAM.  PUSH_PROMISE causes a stream to become "reserved"
  # even if the associated stream has been reset.  Therefore, a
  # RST_STREAM is needed to close an unwanted promised stream.
  when :closed
    if sending
      case frame[:type]
      when :rst_stream, :priority
      else
        stream_error(:stream_closed) unless frame[:type] == :rst_stream
      end
    else
      case @closed
      when :remote_rst, :remote_closed
        case frame[:type]
        when :priority, :rst_stream, :window_update # nop here
        else
          stream_error(:stream_closed)
        end
      when :local_rst, :local_closed
        frame[:ignore] = true if frame[:type] != :window_update
      end
    end
  end
end

#verify_trailers(frame) ⇒ void

This method returns an undefined value.

Parameters:

  • frame (headers_frame) 


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# File 'lib/http/2/stream.rb', line 175

def verify_trailers(frame)
  stream_error(:protocol_error, msg: "trailer headers frame must close the stream") unless end_stream?(frame)
  return unless @_trailers

  trailers = frame[:payload]
  return unless trailers.respond_to?(:each)

  trailers.each do |field, _| # rubocop:disable Style/HashEachMethods
    @_trailers.delete(field)
    break if @_trailers.empty?
  end
  stream_error(:protocol_error, msg: "didn't receive all expected trailer headers") unless @_trailers.empty?
end

#window_update(increment) ⇒ void

This method returns an undefined value.

Sends a WINDOW_UPDATE frame to the peer.

Parameters:

  • increment (Integer) 


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# File 'lib/http/2/stream.rb', line 306

def window_update(increment)
  # emit stream-level WINDOW_UPDATE unless stream is closed
  return if @state == :closed || @state == :remote_closed

  send(type: :window_update, increment: increment)
end