Working example of BasicSocket#readable?.

examples/http1/client.rb

@@ -11,19 +11,70 @@
 require 'async/http/endpoint'
 require 'protocol/http1/connection'
 
-Async do
-	endpoint = Async::HTTP::Endpoint.parse("http://localhost:8080")
-
-	peer = endpoint.connect
+# class IO
+# 	def readable?
+# 		if self.wait_readable(0).nil?
+# 			# timeout means it is not eof
+# 			return true
+# 		else
+# 			!self.eof?
+# 		end
+# 	rescue Errno::EPIPE, Errno::ECONNRESET
+# 		false
+# 	end
+# end
+
+class IO
+	def readable?
+		!self.closed?
+	end
+end
+
+class BasicSocket
+	# Is it likely that the socket is still connected?
+	# May return false positive, but won't return false negative.
+	def readable?
+		return false unless super
+
+		# If we can wait for the socket to become readable, we know that the socket may still be open.
+		result = self.recv_nonblock(1, Socket::MSG_PEEK, exception: false)
+
+		# No data was available - newer Ruby can return nil instead of empty string:
+		return false if result.nil?
+
+		# Either there was some data available, or we can wait to see if there is data avaialble.
+		return !result.empty? || result == :wait_readable
+
+	rescue Errno::ECONNRESET
+		# This might be thrown by recv_nonblock.
+		return false
+	end
+end
+
+def connect(endpoint)
+	peer = endpoint.connect.to_io
 
 	puts "Connected to #{peer} #{peer.remote_address.inspect}"
 
-	# IO Buffering...
-	stream = Async::IO::Stream.new(peer)
-	client = Protocol::HTTP1::Connection.new(stream)
+	return Protocol::HTTP1::Connection.new(peer)
+end
+
+Async do
+	endpoint = Async::HTTP::Endpoint.parse("http://localhost:8080")
+
+	client = connect(endpoint)
 
-	puts "Writing request..."
-	3.times do
+	10.times do
+		puts "Writing request..."
+		# How do we know here whether the client is still good?
+		unless client.stream.readable?
+			puts "Client is not readable, closing..."
+			client.close
+
+			puts "Reconnecting..."
+			client = connect(endpoint)
+		end
+
 		client.write_request("localhost", "GET", "/", "HTTP/1.1", [["Accept", "*/*"]])
 		client.write_body("HTTP/1.1", nil)
 
@@ -33,6 +84,11 @@
 
 		puts "Got response: #{response.inspect}"
 		puts body&.read
+	rescue Errno::ECONNRESET, Errno::EPIPE, EOFError
+		puts "Connection reset by peer."
+
+		# Reconnect and try again:
+		client = connect(endpoint)
 	end
 
 	puts "Closing client..."

examples/http1/server.rb

@@ -25,7 +25,12 @@
 			connection.write_response(version, 200, [["Content-Type", "text/plain"]])
 			connection.write_body(version, Protocol::HTTP::Body::Buffered.wrap(["Hello World"]))
 
+			# Simulate random disconnects:
+			break if rand < 0.5
+
 			break unless connection.persistent
 		end
+	ensure
+		client&.close
 	end
 end