1 files changed, 47 insertions, 0 deletions
diff --git a/lib/puppet/parser/functions/is_domain_name.rb b/lib/puppet/parser/functions/is_domain_name.rb
new file mode 100644
index 0000000..5826dc0
--- /dev/null
+++ b/lib/puppet/parser/functions/is_domain_name.rb
@@ -0,0 +1,47 @@
+#
+# is_domain_name.rb
+#
+
+module Puppet::Parser::Functions
+  newfunction(:is_domain_name, :type => :rvalue, :doc => <<-EOS
+Returns true if the string passed to this function is a syntactically correct domain name.
+    EOS
+  ) do |arguments|
+
+    if (arguments.size != 1) then
+      raise(Puppet::ParseError, "is_domain_name(): Wrong number of arguments "+
+        "given #{arguments.size} for 1")
+    end
+
+    domain = arguments[0]
+
+    # Limits (rfc1035, 3.1)
+    domain_max_length=255
+    label_min_length=1
+    label_max_length=63
+
+    # Allow ".", it is the top level domain
+    return true if domain == '.'
+
+    # Remove the final dot, if present.
+    domain.chomp!('.')
+
+    # Check the whole domain
+    return false if domain.empty?
+    return false if domain.length > domain_max_length
+
+    # Check each label in the domain
+    labels = domain.split('.')
+    vlabels = labels.each do |label|
+      break if label.length < label_min_length
+      break if label.length > label_max_length
+      break if label[-1..-1] == '-'
+      break if label[0..0] == '-'
+      break unless /^[a-z\d-]+$/i.match(label)
+    end
+    return vlabels == labels
+
+  end
+end
+
+# vim: set ts=2 sw=2 et :