DNS resolution blocking

test-dns-resolution.rb

@@ -0,0 +1,74 @@
+require 'eventmachine'
+require 'em/resolver'
+require 'em-http-request'
+require 'em-resolv-replace'
+
+puts "Using #{EventMachine::DNS::Resolver::Port}"
+
+class Request < EventMachine::Connection
+  def post_init
+    puts "Sending GET request"
+    send_data "GET /\n\n"
+  end
+
+  def receive_data(data)
+    puts "Reponse:\n#{data}"
+    EventMachine.stop
+  end
+end
+
+def connect_and_stop(host, port)
+  puts "#{Time.now}: Starting socket test for #{host}:#{port}"
+  EventMachine.run do
+    EventMachine::PeriodicTimer.new(0.2) { puts "#{Time.now}: ...tick socket... #{host}:#{port}" }
+    EventMachine::Timer.new(5) { puts "#{Time.now}: Socket timed out for #{host}:#{port}"; EventMachine.stop }
+    EventMachine::connect host, port, Request
+  end
+end
+
+def http_request(host, port)
+  puts "#{Time.now}: Starting EM-HTTP test for #{host}:#{port}"
+  EventMachine.run do
+    EventMachine::PeriodicTimer.new(0.2) { puts "#{Time.now}: ...tick http... #{host}:#{port}" }
+    EventMachine::Timer.new(5) { puts "#{Time.now}: HTTP timed out for #{host}:#{port}"; EventMachine.stop }
+    http = EventMachine::HttpRequest.new("http://#{host}:#{port}/").get
+    http.errback do
+      puts "#{Time.now}: Error - HTTP request failed #{host}:#{port}"
+      EventMachine.stop
+    end
+    http.callback do |result|
+      puts "#{Time.now}: HTTP request successful http://#{host}:#{port}/"
+      EventMachine.stop
+    end
+  end
+end
+
+def resolve_dns(host)
+  puts "#{Time.now}: Resolving DNS for #{host}"
+  EventMachine.run do
+    EventMachine::PeriodicTimer.new(0.2) { puts "#{Time.now}: ...tick DNS resolving for #{host}..." }
+    EventMachine::Timer.new(5) { puts "#{Time.now}: Timed out resolving host #{host}"; EventMachine.stop }
+    dns = EventMachine::DNS::Resolver.resolve host
+    dns.errback do
+      puts "#{Time.now}: Error - could not resolve DNS #{host}"
+      EventMachine.stop
+    end
+    dns.callback do |result|
+      puts "#{Time.now}: Resolved #{host} to #{result}"
+      EventMachine.stop
+    end
+  end
+end
+
+# valid_host = "www.google.com"
+# resolve_dns valid_host
+# connect_and_stop valid_host, 80
+# connect_and_stop valid_host, 14441
+# http_request valid_host, 80
+
+invalid_host = "this.host.does.not.exist"
+require 'pry'; binding.pry
+# resolve_dns invalid_host
+
+# http_request invalid_host, 80
+connect_and_stop invalid_host, 80