Translate asterisks in ip addresses to mask format so people can enter things like 127.*.*.* in screened ip addresses form

app/models/screened_ip_address.rb

@@ -18,7 +18,22 @@ class ScreenedIpAddress < ActiveRecord::Base
   # In Rails 4.0.1, an exception is raised before validation happens, so we need this hack for
   # inet/cidr columns:
   def ip_address=(val)
+    if val.nil?
+      self.errors.add(:ip_address, :invalid)
+      return
+    end
+
+    num_wildcards = val.count('*')
+    if num_wildcards == 0
       write_attribute(:ip_address, val)
+    else
+      v = val.gsub(/\/.*/, '')
+      if v[v.index('*')..-1] =~ /[^\.\*]/
+        self.errors.add(:ip_address, :invalid)
+        return
+      end
+      write_attribute(:ip_address, "#{v.gsub('*', '0')}/#{32 - (num_wildcards * 8)}")
+    end
 
   # this gets even messier, Ruby 1.9.2 raised a different exception to Ruby 2.0.0
   # handle both exceptions

spec/models/screened_ip_address_spec.rb

@@ -47,6 +47,45 @@ describe ScreenedIpAddress do
     end
   end
 
+  describe "ip_address=" do
+    let(:record) { described_class.new }
+
+    def test_good_value(arg, expected)
+      record.ip_address = arg
+      record.ip_address_with_mask.should == expected
+    end
+
+    def test_bad_value(arg)
+      r = described_class.new
+      r.ip_address = arg
+      r.should_not be_valid
+      r.errors[:ip_address].should be_present
+    end
+
+    it "handles valid ip addresses" do
+      test_good_value("210.56.12.12", "210.56.12.12")
+      test_good_value("210.56.0.0/16", "210.56.0.0/16")
+      test_good_value("fc00::/7", "fc00::/7")
+    end
+
+    it "translates * characters" do
+      test_good_value("123.*.*.*",     "123.0.0.0/8")
+      test_good_value("123.12.*.*",    "123.12.0.0/16")
+      test_good_value("123.12.1.*",    "123.12.1.0/24")
+      test_good_value("123.12.*.*/16", "123.12.0.0/16")
+    end
+
+    it "handles bad input" do
+      test_bad_value(nil)
+      test_bad_value("123.123")
+      test_bad_value("my house")
+      test_bad_value("123.*.1.12")
+      test_bad_value("*.123.*.12")
+      test_bad_value("*.*.*.12")
+      test_bad_value("123.*.1.12/8")
+    end
+  end
+
   describe '#watch' do
     context 'ip_address is not being watched' do
       it 'should create a new record' do
@@ -122,8 +161,6 @@ describe ScreenedIpAddress do
     it "doesn't block fc00::/7 addresses (IPv6)" do
       described_class.watch('fd12:db8::ff00:42:8329').action_type.should == described_class.actions[:do_nothing]
     end
-
-
   end
 
   describe '#should_block?' do