Class: Protocol::HTTP2::Connection

Inherits:
Object
  • Object
show all
Includes:
FlowControl
Defined in:
lib/protocol/http2/connection.rb

Direct Known Subclasses

Client, Server

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from FlowControl

#available_frame_size, #consume_local_window, #consume_remote_window, #send_window_update

Constructor Details

#initialize(framer, local_stream_id) ⇒ Connection

Returns a new instance of Connection.



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# File 'lib/protocol/http2/connection.rb', line 31

def initialize(framer, local_stream_id)
	@state = :new
	@streams = {}
	
	@framer = framer
	@local_stream_id = local_stream_id
	@remote_stream_id = 0
	
	@local_settings = PendingSettings.new
	@remote_settings = Settings.new
	
	@decoder = HPACK::Context.new
	@encoder = HPACK::Context.new
	
	@local_window = Window.new(@local_settings.initial_window_size)
	@remote_window = Window.new(@remote_settings.initial_window_size)
end

Instance Attribute Details

#framer ⇒ Object (readonly)

Returns the value of attribute framer.



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# File 'lib/protocol/http2/connection.rb', line 62

def framer
  @framer
end

#local_settings ⇒ Object

Current settings value for local and peer



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# File 'lib/protocol/http2/connection.rb', line 68

def local_settings
  @local_settings
end

#local_window ⇒ Object (readonly)

Our window for receiving data. When we receive data, it reduces this window. If the window gets too small, we must send a window update.



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# File 'lib/protocol/http2/connection.rb', line 73

def local_window
  @local_window
end

#remote_settings ⇒ Object

Returns the value of attribute remote_settings.



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# File 'lib/protocol/http2/connection.rb', line 69

def remote_settings
  @remote_settings
end

#remote_stream_id ⇒ Object (readonly)

The highest stream_id that has been successfully accepted by this connection.



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# File 'lib/protocol/http2/connection.rb', line 79

def remote_stream_id
  @remote_stream_id
end

#remote_window ⇒ Object (readonly)

Our window for sending data. When we send data, it reduces this window.



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# File 'lib/protocol/http2/connection.rb', line 76

def remote_window
  @remote_window
end

#state ⇒ Object

Connection state (:new, :open, :closed).



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# File 'lib/protocol/http2/connection.rb', line 65

def state
  @state
end

#streams ⇒ Object (readonly)

Returns the value of attribute streams.



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# File 'lib/protocol/http2/connection.rb', line 115

def streams
  @streams
end

Instance Method Details

#accept_push_promise_stream(stream_id, &block) ⇒ Object

Accept an incoming push promise from the other side of the connection. On the client side, we accept push promise streams. On the server side, existing streams create push promise streams.



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# File 'lib/protocol/http2/connection.rb', line 322

def accept_push_promise_stream(stream_id, &block)
	accept_stream(stream_id, &block)
end

#accept_stream(stream_id, &block) ⇒ Object

Accept an incoming stream from the other side of the connnection. On the server side, we accept requests.



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# File 'lib/protocol/http2/connection.rb', line 305

def accept_stream(stream_id, &block)
	unless valid_remote_stream_id?(stream_id)
		raise ProtocolError, "Invalid remote stream id: #{stream_id}"
	end
	
	if stream_id <= @remote_stream_id
		raise ProtocolError, "Invalid stream id: #{stream_id} <= #{@remote_stream_id}!"
	end
	
	@remote_stream_id = stream_id
	
	create_stream(stream_id, &block)
end

#active_streams ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 85

def active_streams
	@streams.each_value.select(&:active?)
end

#close(error = nil) ⇒ Object

Close the underlying framer and all streams.



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# File 'lib/protocol/http2/connection.rb', line 90

def close(error = nil)
	@framer.close
	
	@streams.each_value{|stream| stream.close(error)}
end

#close! ⇒ Object

Transition the connection into the closed state.



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# File 'lib/protocol/http2/connection.rb', line 170

def close!
	@state = :closed
	
	return self
end

#closed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/protocol/http2/connection.rb', line 81

def closed?
	@state == :closed
end

#create_push_promise_stream(&block) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 343

def create_push_promise_stream(&block)
	create_stream(&block)
end

#create_stream(stream_id = next_stream_id, &block) ⇒ Stream

Create a stream, defaults to an outgoing stream. On the client side, we create requests.

Returns:

  • (Stream) —

    the created stream.



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# File 'lib/protocol/http2/connection.rb', line 329

def create_stream(stream_id = next_stream_id, &block)
	if block_given?
		yield(stream_id)
	else
		return Stream.new(self, stream_id)
	end
	
	if stream = @streams[stream_id]
		return stream
	else
		raise ProtocolError, "Stream creation failed!"
	end
end

#decode_headers(data) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 102

def decode_headers(data)
	HPACK::Decompressor.new(data, @decoder).decode
end

#encode_headers(headers, buffer = String.new.b) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 96

def encode_headers(headers, buffer = String.new.b)
	HPACK::Compressor.new(buffer, @encoder).encode(headers)
	
	return buffer
end

#id ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 49

def id
	0
end

#ignore_frame?(frame) ⇒ Boolean

6.8. GOAWAY There is an inherent race condition between an endpoint starting new streams and the remote sending a GOAWAY frame. To deal with this case, the GOAWAY contains the stream identifier of the last peer-initiated stream that was or might be processed on the sending endpoint in this connection. For instance, if the server sends a GOAWAY frame, the identified stream is the highest-numbered stream initiated by the client. Once sent, the sender will ignore frames sent on streams initiated by the receiver if the stream has an identifier higher than the included last stream identifier. Receivers of a GOAWAY frame MUST NOT open additional streams on the connection, although a new connection can be established for new streams.

Returns:

  • (Boolean) 


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# File 'lib/protocol/http2/connection.rb', line 120

def ignore_frame?(frame)
	if self.closed?
		puts "ignore_frame? #{frame.stream_id} -> #{valid_remote_stream_id?(frame.stream_id)} > #{@remote_stream_id}"
		if valid_remote_stream_id?(frame.stream_id)
			return frame.stream_id > @remote_stream_id
		end
	end
end

#maximum_concurrent_streams ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 58

def maximum_concurrent_streams
	[@local_settings.maximum_concurrent_streams, @remote_settings.maximum_concurrent_streams].min
end

#maximum_frame_size ⇒ Object

The size of a frame payload is limited by the maximum size that a receiver advertises in the SETTINGS_MAX_FRAME_SIZE setting.



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# File 'lib/protocol/http2/connection.rb', line 54

def maximum_frame_size
	@remote_settings.maximum_frame_size
end

#next_stream_id ⇒ Object

Streams are identified with an unsigned 31-bit integer. Streams initiated by a client MUST use odd-numbered stream identifiers; those initiated by the server MUST use even-numbered stream identifiers. A stream identifier of zero (0x0) is used for connection control messages; the stream identifier of zero cannot be used to establish a new stream.



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# File 'lib/protocol/http2/connection.rb', line 107

def next_stream_id
	id = @local_stream_id
	
	@local_stream_id += 2
	
	return id
end

#open! ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 256

def open!
	@state = :open
	
	return self
end

#process_settings(frame) ⇒ Boolean

In addition to changing the flow-control window for streams that are not yet active, a SETTINGS frame can alter the initial flow-control window size for streams with active flow-control windows (that is, streams in the “open” or “half-closed (remote)” state). When the value of SETTINGS_INITIAL_WINDOW_SIZE changes, a receiver MUST adjust the size of all stream flow-control windows that it maintains by the difference between the new value and the old value.

Returns:

  • (Boolean) —

    whether the frame was an acknowledgement



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# File 'lib/protocol/http2/connection.rb', line 233

def process_settings(frame)
	if frame.acknowledgement?
		# The remote end has confirmed the settings have been received:
		changes = @local_settings.acknowledge
		
		update_local_settings(changes)
		
		return true
	else
		# The remote end is updating the settings, we reply with acknowledgement:
		reply = frame.acknowledge
		
		write_frame(reply)
		
		changes = frame.unpack
		@remote_settings.update(changes)
		
		update_remote_settings(changes)
		
		return false
	end
end

#read_frame ⇒ Object

Reads one frame from the network and processes. Processing the frame updates the state of the connection and related streams. If the frame triggers an error, e.g. a protocol error, the connection will typically emit a goaway frame and re-raise the exception. You should continue processing frames until the underlying connection is closed.



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# File 'lib/protocol/http2/connection.rb', line 130

def read_frame
	frame = @framer.read_frame(@local_settings.maximum_frame_size)
	# puts "#{self.class} #{@state} read_frame: class=#{frame.class} stream_id=#{frame.stream_id} flags=#{frame.flags} length=#{frame.length} (remote_stream_id=#{@remote_stream_id})"
	# puts "Windows: local_window=#{@local_window.inspect}; remote_window=#{@remote_window.inspect}"
	
	return if ignore_frame?(frame)
	
	yield frame if block_given?
	frame.apply(self)
	
	return frame
rescue GoawayError => error
	# Go directly to jail. Do not pass go, do not collect $200.
	self.close(error)
	
	raise
rescue ProtocolError => error
	send_goaway(error.code || PROTOCOL_ERROR, error.message)
	
	raise
rescue HPACK::CompressionError => error
	send_goaway(COMPRESSION_ERROR, error.message)
	
	raise
rescue
	send_goaway(PROTOCOL_ERROR, $!.message)
	
	raise
end

#receive_continuation(frame) ⇒ Object

Raises:



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# File 'lib/protocol/http2/connection.rb', line 409

def receive_continuation(frame)
	raise ProtocolError, "Received unexpected continuation: #{frame.class}"
end

#receive_data(frame) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 289

def receive_data(frame)
	consume_local_window(frame)
	
	if stream = @streams[frame.stream_id]
		stream.receive_data(frame)
	else
		raise ProtocolError, "Cannot receive data for idle stream #{frame.stream_id}"
	end
end

#receive_frame(frame) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 413

def receive_frame(frame)
	# ignore.
end

#receive_goaway(frame) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 186

def receive_goaway(frame)
	# We capture the last stream that was processed.
	@remote_stream_id, error_code, message = frame.unpack
	
	self.close!
	
	if error_code != 0
		# Shut down immediately.
		raise GoawayError.new(message, error_code)
	end
end

#receive_headers(frame) ⇒ Object

On the server side, starts a new request.



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# File 'lib/protocol/http2/connection.rb', line 348

def receive_headers(frame)
	if frame.stream_id == 0
		raise ProtocolError, "Cannot receive headers for stream 0!"
	end
	
	if stream = @streams[frame.stream_id]
		stream.receive_headers(frame)
	else
		if self.active_streams.count < self.maximum_concurrent_streams
			stream = accept_stream(frame.stream_id)
			stream.receive_headers(frame)
		else
			raise ProtocolError, "Exceeded maximum concurrent streams"
		end
	end
end

#receive_ping(frame) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 273

def receive_ping(frame)
	if @state != :closed
		if frame.stream_id != 0
			raise ProtocolError, "Ping received for non-zero stream!"
		end
		
		unless frame.acknowledgement?
			reply = frame.acknowledge
			
			write_frame(reply)
		end
	else
		raise ProtocolError, "Cannot receive ping in state #{@state}"
	end
end

#receive_priority(frame) ⇒ Object

On the client and server side, sets the priority for an incoming stream.



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# File 'lib/protocol/http2/connection.rb', line 366

def receive_priority(frame)
	if stream = @streams[frame.stream_id]
		stream.receive_priority(frame)
	else
		stream = accept_stream(frame.stream_id)
		stream.receive_priority(frame)
	end
end

#receive_push_promise(frame) ⇒ Object

Raises:



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# File 'lib/protocol/http2/connection.rb', line 375

def receive_push_promise(frame)
	raise ProtocolError, "Unable to receive push promise!"
end

#receive_reset_stream(frame) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 379

def receive_reset_stream(frame)
	if stream = @streams[frame.stream_id]
		stream.receive_reset_stream(frame)
	else
		raise StreamClosed, "Cannot reset stream #{frame.stream_id}"
	end
end

#receive_settings(frame) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 262

def receive_settings(frame)
	if @state == :new
		# We transition to :open when we receive acknowledgement of first settings frame:
		open! if process_settings(frame)
	elsif @state != :closed
		process_settings(frame)
	else
		raise ProtocolError, "Cannot receive settings in state #{@state}"
	end
end

#receive_window_update(frame) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 387

def receive_window_update(frame)
	if frame.connection?
		super
	elsif stream = @streams[frame.stream_id]
		begin
			stream.receive_window_update(frame)
		rescue ProtocolError => error
			stream.send_reset_stream(error.code)
		end
	else
		# Receiving any frame other than HEADERS or PRIORITY on a stream in this state MUST be treated as a connection error of type PROTOCOL_ERROR.
		raise ProtocolError, "Cannot update window of idle stream #{frame.stream_id}"
	end
end

#send_goaway(error_code = 0, message = "") ⇒ Object

Tell the remote end that the connection is being shut down. If the ‘error_code` is 0, this is a graceful shutdown. The other end of the connection should not make any new streams, but existing streams may be completed.



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# File 'lib/protocol/http2/connection.rb', line 177

def send_goaway(error_code = 0, message = "")
	frame = GoawayFrame.new
	frame.pack @remote_stream_id, error_code, message
	
	write_frame(frame)
	
	self.close!
end

#send_ping(data) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 203

def send_ping(data)
	if @state != :closed
		frame = PingFrame.new
		frame.pack data
		
		write_frame(frame)
	else
		raise ProtocolError, "Cannot send ping in state #{@state}"
	end
end

#send_settings(changes) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 160

def send_settings(changes)
	@local_settings.append(changes)
	
	frame = SettingsFrame.new
	frame.pack(changes)
	
	write_frame(frame)
end

#update_local_settings(changes) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 214

def update_local_settings(changes)
	capacity = @local_settings.initial_window_size
	
	@streams.each_value do |stream|
		stream.local_window.capacity = capacity
	end
end

#update_remote_settings(changes) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 222

def update_remote_settings(changes)
	capacity = @remote_settings.initial_window_size
	
	@streams.each_value do |stream|
		stream.remote_window.capacity = capacity
	end
end

#valid_remote_stream_id? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/protocol/http2/connection.rb', line 299

def valid_remote_stream_id?
	false
end

#window_updated ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 402

def window_updated
	# This is very inefficient, but workable.
	@streams.each_value do |stream|
		stream.window_updated unless stream.closed?
	end
end

#write_frame(frame) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 198

def write_frame(frame)
	# puts "#{self.class} #{@state} write_frame: class=#{frame.class} flags=#{frame.flags} length=#{frame.length}"
	@framer.write_frame(frame)
end