working through 14.4

cookbook/014/04-list-a-to-z-domain-addrs-concurrent.rb

@@ -0,0 +1,29 @@
+require 'resolv'
+require 'resolv-replace'
+
+
+def multiple_lookup(*names)
+    dns = Resolv::DNS.new
+    results = {}
+    threads = []
+    names.each do |name|
+        threads << Thread.new(name) do |name|
+            begin
+                dns.each_address(name) { |a| (results[name] ||= []) << a }
+            rescue Resolv::ResolvError
+                results[name] = nil
+            end
+        end
+    end
+    threads.each { |t| t.join }
+    return results
+end
+
+
+domains = ("a".."z").collect { |l| l + '.com' }
+multiple_lookup(*domains).sort.each do |name, addresses|
+    if addresses
+        puts "#{name}: #{addresses.size} " + \
+             "address#{addresses.size == 1 ? "" : "es"}"
+    end
+end

cookbook/014/04-list-oreilly-mx-ns.rb

@@ -0,0 +1,11 @@
+require 'resolv'
+
+dns = Resolv::DNS.new
+domain = "oreilly.com"
+dns.each_resource(domain, Resolv::DNS::Resource::IN::MX) do |mail_server|
+    puts mail_server.exchange
+end
+
+dns.each_resource(domain, Resolv::DNS::Resource::IN::NS) do |nameserver|
+    puts nameserver.name
+end

cookbook/014/04.rb

@@ -0,0 +1,3 @@
+require 'resolv'
+
+Resolv::DNS.new.each_address('oreilly.com') { |addr| puts addr }