# frozen_string_literal: true require "resolv" require "forwardable" require "httpx/io" require "httpx/buffer" module HTTPX # The Connection can be watched for IO events. # # It contains the +io+ object to read/write from, and knows what to do when it can. # # It defers connecting until absolutely necessary. Connection should be triggered from # the IO selector (until then, any request will be queued). # # A connection boots up its parser after connection is established. All pending requests # will be redirected there after connection. # # A connection can be prevented from closing by the parser, that is, if there are pending # requests. This will signal that the connection was prematurely closed, due to a possible # number of conditions: # # * Remote peer closed the connection ("Connection: close"); # * Remote peer doesn't support pipelining; # # A connection may also route requests for a different host for which the +io+ was connected # to, provided that the IP is the same and the port and scheme as well. This will allow to # share the same socket to send HTTP/2 requests to different hosts. # class Connection extend Forwardable include Registry include Loggable include Callbacks using URIExtensions require "httpx/connection/http2" require "httpx/connection/http1" BUFFER_SIZE = 1 << 14 def_delegator :@io, :closed? def_delegator :@write_buffer, :empty? attr_reader :origin, :state, :pending, :options attr_writer :timers def initialize(type, uri, options) @type = type @origins = [uri.origin] @origin = Utils.to_uri(uri.origin) @options = Options.new(options) @window_size = @options.window_size @read_buffer = Buffer.new(BUFFER_SIZE) @write_buffer = Buffer.new(BUFFER_SIZE) @pending = [] on(:error, &method(:on_error)) if @options.io # if there's an already open IO, get its # peer address, and force-initiate the parser transition(:already_open) @io = IO.registry(@type).new(@origin, nil, @options) parser else transition(:idle) end @inflight = 0 @keep_alive_timeout = @options.timeout[:keep_alive_timeout] @keep_alive_timer = nil self.addresses = @options.addresses if @options.addresses end # this is a semi-private method, to be used by the resolver # to initiate the io object. def addresses=(addrs) @io ||= IO.registry(@type).new(@origin, addrs, @options) # rubocop:disable Naming/MemoizedInstanceVariableName end def addresses @io && @io.addresses end def match?(uri, options) return false if @state == :closing || @state == :closed return false if exhausted? ( ( @origins.include?(uri.origin) && # if there is more than one origin to match, it means that this connection # was the result of coalescing. To prevent blind trust in the case where the # origin came from an ORIGIN frame, we're going to verify the hostname with the # SSL certificate (@origins.size == 1 || @origin == uri.origin || (@io && @io.verify_hostname(uri.host))) ) || match_altsvcs?(uri) ) && @options == options end def mergeable?(connection) return false if @state == :closing || @state == :closed || !@io return false if exhausted? return false unless connection.addresses !(@io.addresses & connection.addresses).empty? && @options == connection.options end # coalescable connections need to be mergeable! # but internally, #mergeable? is called before #coalescable? def coalescable?(connection) if @io.protocol == "h2" && @origin.scheme == "https" && connection.origin.scheme == "https" @io.verify_hostname(connection.origin.host) else @origin == connection.origin end end def create_idle(options = {}) self.class.new(@type, @origin, @options.merge(options)) end def merge(connection) @origins |= connection.instance_variable_get(:@origins) connection.purge_pending do |req| send(req) end end def purge_pending(&block) pendings = [] if @parser @inflight -= @parser.pending.size pendings << @parser.pending end pendings << @pending pendings.each do |pending| pending.reject!(&block) end end # checks if this is connection is an alternative service of # +uri+ def match_altsvcs?(uri) @origins.any? { |origin| uri.altsvc_match?(origin) } || AltSvc.cached_altsvc(@origin).any? do |altsvc| origin = altsvc["origin"] origin.altsvc_match?(uri.origin) end end def connecting? @state == :idle end def inflight? @parser && !@parser.empty? && !@write_buffer.empty? end def interests # connecting if connecting? connect return @io.interests if connecting? end # if the write buffer is full, we drain it return :w unless @write_buffer.empty? return @parser.interests if @parser nil end def to_io @io.to_io end def call case @state when :closed return when :closing consume transition(:closed) emit(:close) when :open consume end nil end def close @parser.close if @parser return unless @keep_alive_timer @keep_alive_timer.cancel remove_instance_variable(:@keep_alive_timer) end def reset transition(:closing) transition(:closed) emit(:close) end def send(request) if @parser && !@write_buffer.full? request.headers["alt-used"] = @origin.authority if match_altsvcs?(request.uri) if @keep_alive_timer # when pushing a request into an existing connection, we have to check whether there # is the possibility that the connection might have extended the keep alive timeout. # for such cases, we want to ping for availability before deciding to shovel requests. if @keep_alive_timer.fires_in.negative? @pending << request parser.ping return end @keep_alive_timer.pause end @inflight += 1 parser.send(request) else @pending << request end end def timeout return @timeout if defined?(@timeout) return @options.timeout[:connect_timeout] if @state == :idle @options.timeout[:operation_timeout] end private def connect transition(:open) end def exhausted? @parser && parser.exhausted? end def consume return unless @io catch(:called) do epiped = false loop do parser.consume # we exit if there's no more requests to process # # this condition takes into account: # # * the number of inflight requests # * the number of pending requests # * whether the write buffer has bytes (i.e. for close handshake) if @pending.size.zero? && @inflight.zero? && @write_buffer.empty? log(level: 3) { "NO MORE REQUESTS..." } return end @timeout = @current_timeout read_drained = false write_drained = nil # # tight read loop. # # read as much of the socket as possible. # # this tight loop reads all the data it can from the socket and pipes it to # its parser. # loop do siz = @io.read(@window_size, @read_buffer) log(level: 3, color: :cyan) { "IO READ: #{siz} bytes..." } unless siz ex = EOFError.new("descriptor closed") ex.set_backtrace(caller) on_error(ex) return end # socket has been drained. mark and exit the read loop. if siz.zero? read_drained = @read_buffer.empty? epiped = false break end parser << @read_buffer.to_s # continue reading if possible. break if interests == :w && !epiped # exit the read loop if connection is preparing to be closed break if @state == :closing || @state == :closed # exit #consume altogether if all outstanding requests have been dealt with return if @pending.size.zero? && @inflight.zero? end unless ((ints = interests).nil? || ints == :w || @state == :closing) && !epiped # # tight write loop. # # flush as many bytes as the sockets allow. # loop do # buffer has been drainned, mark and exit the write loop. if @write_buffer.empty? # we only mark as drained on the first loop write_drained = write_drained.nil? && @inflight.positive? break end begin siz = @io.write(@write_buffer) rescue Errno::EPIPE # this can happen if we still have bytes in the buffer to send to the server, but # the server wants to respond immediately with some message, or an error. An example is # when one's uploading a big file to an unintended endpoint, and the server stops the # consumption, and responds immediately with an authorization of even method not allowed error. # at this point, we have to let the connection switch to read-mode. log(level: 2) { "pipe broken, could not flush buffer..." } epiped = true read_drained = false break end log(level: 3, color: :cyan) { "IO WRITE: #{siz} bytes..." } unless siz ex = EOFError.new("descriptor closed") ex.set_backtrace(caller) on_error(ex) return end # socket closed for writing. mark and exit the write loop. if siz.zero? write_drained = !@write_buffer.empty? break end # exit write loop if marked to consume from peer, or is closing. break if interests == :r || @state == :closing || @state == :closed write_drained = false end unless (ints = interests) == :r send_pending if @state == :open # return if socket is drained next unless (ints != :r || read_drained) && (ints != :w || write_drained) # gotta go back to the event loop. It happens when: # # * the socket is drained of bytes or it's not the interest of the conn to read; # * theres nothing more to write, or it's not in the interest of the conn to write; log(level: 3) { "(#{ints}): WAITING FOR EVENTS..." } return end end end def send_pending while !@write_buffer.full? && (request = @pending.shift) @inflight += 1 @keep_alive_timer.pause if @keep_alive_timer parser.send(request) end end def parser @parser ||= build_parser end def build_parser(protocol = @io.protocol) parser = registry(protocol).new(@write_buffer, @options) set_parser_callbacks(parser) parser end def set_parser_callbacks(parser) parser.on(:response) do |request, response| AltSvc.emit(request, response) do |alt_origin, origin, alt_params| emit(:altsvc, alt_origin, origin, alt_params) end handle_response request.emit(:response, response) end parser.on(:altsvc) do |alt_origin, origin, alt_params| emit(:altsvc, alt_origin, origin, alt_params) end parser.on(:pong, &method(:send_pending)) parser.on(:promise) do |request, stream| request.emit(:promise, parser, stream) end parser.on(:exhausted) do emit(:exhausted) end parser.on(:origin) do |origin| @origins |= [origin] end parser.on(:close) do |force| transition(:closing) if force transition(:closed) emit(:close) end end parser.on(:close_handshake) do consume end parser.on(:reset) do if parser.empty? reset else transition(:closing) transition(:closed) emit(:reset) @parser.reset if @parser transition(:idle) transition(:open) end end parser.on(:current_timeout) do @current_timeout = @timeout = parser.timeout end parser.on(:timeout) do |tout| @timeout = tout end parser.on(:error) do |request, ex| case ex when MisdirectedRequestError emit(:misdirected, request) else response = ErrorResponse.new(request, ex, @options) request.response = response request.emit(:response, response) end end end def transition(nextstate) case nextstate when :idle @timeout = @current_timeout = @options.timeout[:connect_timeout] when :open return if @state == :closed total_timeout @io.connect return unless @io.connected? send_pending @timeout = @current_timeout = parser.timeout emit(:open) when :closing return unless @state == :open when :closed return unless @state == :closing return unless @write_buffer.empty? if @total_timeout @total_timeout.cancel remove_instance_variable(:@total_timeout) end purge_after_closed when :already_open nextstate = :open send_pending end @state = nextstate rescue Errno::ECONNREFUSED, Errno::EADDRNOTAVAIL, Errno::EHOSTUNREACH, TLSError => e # connect errors, exit gracefully handle_error(e) @state = :closed emit(:close) end def purge_after_closed @io.close if @io @read_buffer.clear if @keep_alive_timer @keep_alive_timer.cancel remove_instance_variable(:@keep_alive_timer) end remove_instance_variable(:@timeout) if defined?(@timeout) end def handle_response @inflight -= 1 return unless @inflight.zero? if @keep_alive_timer @keep_alive_timer.resume @keep_alive_timer.reset else @keep_alive_timer = @timers.after(@keep_alive_timeout) do unless @inflight.zero? log { "(#{@origin}): keep alive timeout expired" } parser.ping end end end end def on_error(error) if error.instance_of?(TimeoutError) if @timeout @timeout -= error.timeout return unless @timeout <= 0 end if @total_timeout && @total_timeout.fires_in.negative? ex = TotalTimeoutError.new(@total_timeout.interval, "Timed out after #{@total_timeout.interval} seconds") ex.set_backtrace(error.backtrace) error = ex elsif connecting? error = error.to_connection_error end end handle_error(error) reset end def handle_error(error) parser.handle_error(error) if @parser && parser.respond_to?(:handle_error) while (request = @pending.shift) response = ErrorResponse.new(request, error, @options) request.response = response request.emit(:response, response) end end def total_timeout total = @options.timeout[:total_timeout] return unless total @total_timeout ||= @timers.after(total) do ex = TotalTimeoutError.new(total, "Timed out after #{total} seconds") ex.set_backtrace(caller) on_error(ex) @parser.close if @parser end end end end