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, #available_size, #consume_local_window, #consume_remote_window, #consume_window, #send_window_update, #window_updated

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)
	super()
	
	@state = :new
	@streams = {}
	@children = {}
	
	@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

#children ⇒ Object (readonly)

Returns the value of attribute children.



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# File 'lib/protocol/http2/connection.rb', line 132

def children
  @children
end

#framer ⇒ Object (readonly)

Returns the value of attribute framer.



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# File 'lib/protocol/http2/connection.rb', line 77

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 83

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 88

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 84

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 94

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 91

def remote_window
  @remote_window
end

#state ⇒ Object

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



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# File 'lib/protocol/http2/connection.rb', line 80

def state
  @state
end

#streams ⇒ Object (readonly)

Returns the value of attribute streams.



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# File 'lib/protocol/http2/connection.rb', line 131

def streams
  @streams
end

Instance Method Details

#[](id) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 60

def [] id
	if id.zero?
		self
	else
		@streams[id]
	end
end

#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 351

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 340

def accept_stream(stream_id, &block)
	unless valid_remote_stream_id?(stream_id)
		raise ProtocolError, "Invalid stream id: #{stream_id}"
	end
	
	create_stream(stream_id, &block)
end

#active_streams ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 100

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

#add_child(stream) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 134

def add_child(stream)
	@children[stream.id] = stream
end

#close(error = nil) ⇒ Object

Close the underlying framer and all streams.



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# File 'lib/protocol/http2/connection.rb', line 106

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 201

def close!
	@state = :closed
	
	return self
end

#closed? ⇒ Boolean

Returns:

  • (Boolean) 


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

def closed?
	@state == :closed
end

#create_push_promise_stream(&block) ⇒ Object 



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

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

#create_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 358

def create_stream(id = next_stream_id, &block)
	if block_given?
		return yield(self, id)
	else
		return Stream.create(self, id)
	end
end

#decode_headers(data) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 118

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

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



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# File 'lib/protocol/http2/connection.rb', line 112

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

#exclusive_child(stream) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 142

def exclusive_child(stream)
	stream.children = @children
	
	@children.each do |child|
		child.dependent_id = stream.id
	end
	
	@children = {stream.id => stream}
	
	stream.dependent_id = 0
end

#id ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 52

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 157

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 73

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 69

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 123

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 291

def open!
	@state = :open
	
	return self
end

#parent ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 56

def parent
	nil
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 268

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 167

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.
	raise
rescue ProtocolError => error
	send_goaway(error.code || PROTOCOL_ERROR, error.message)
	
	raise
rescue HPACK::CompressionError => error
	send_goaway(COMPRESSION_ERROR, error.message)
	
	raise
end

#receive_continuation(frame) ⇒ Object

Raises:



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# File 'lib/protocol/http2/connection.rb', line 436

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 324

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 440

def receive_frame(frame)
	# ignore.
end

#receive_goaway(frame) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 217

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 371

def receive_headers(frame)
	stream_id = frame.stream_id
	
	if stream_id.zero?
		raise ProtocolError, "Cannot receive headers for stream 0!"
	end
	
	if stream = @streams[stream_id]
		stream.receive_headers(frame)
	else
		if stream_id <= @remote_stream_id
			raise ProtocolError, "Invalid stream id: #{stream_id} <= #{@remote_stream_id}!"
		end
		
		if self.active_streams.count < self.maximum_concurrent_streams
			stream = accept_stream(stream_id)
			@remote_stream_id = 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 308

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 397

def receive_priority(frame)
	if stream = @streams[frame.stream_id]
		stream.receive_priority(frame)
	else
		# Stream doesn't exist yet.
		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 407

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 411

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 297

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 419

def receive_window_update(frame)
	if frame.connection?
		super
		
		self.consume_window
	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

#remove_child(stream) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 138

def remove_child(stream)
	@children.delete(stream.id)
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 208

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

#send_ping(data) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 234

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 191

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 245

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

#update_remote_settings(changes) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 255

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

#valid_remote_stream_id? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/protocol/http2/connection.rb', line 334

def valid_remote_stream_id?
	false
end

#write_frame(frame) ⇒ Object 



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# File 'lib/protocol/http2/connection.rb', line 229

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