views: convert 'ip' (bigint) -> 'ip_address' (inet)

This fixes all known issues when connecting to discourse over IPv6.

This table has no primary key, so the migration is done with update_all,
for each ip address in the views table. Since this table can potentially
grow quite large, this process might take a long time. I don't know any
way around this, though.

This migration uses a SQL command to populate the new field from the old
one, so as not to rely on the View model class, which should keep the
migration from failing if that class is modified in the future.

app/models/view.rb

@@ -3,7 +3,7 @@ require 'ipaddr'
 class View < ActiveRecord::Base
   belongs_to :parent, polymorphic: true
   belongs_to :user
-  validates_presence_of :parent_type, :parent_id, :ip, :viewed_at
+  validates_presence_of :parent_type, :parent_id, :ip_address, :viewed_at
 
   # TODO: This could happen asyncronously
   def self.create_for(parent, ip, user=nil)
@@ -20,7 +20,7 @@ class View < ActiveRecord::Base
       $redis.expire(redis_key, 1.day.to_i)
 
       View.transaction do
-        View.create(parent: parent, ip: IPAddr.new(ip).to_i, viewed_at: Date.today, user: user)
+        View.create(parent: parent, ip_address: ip, viewed_at: Date.today, user: user)
 
         # Update the views count in the parent, if it exists.
         if parent.respond_to?(:views)
@@ -37,9 +37,9 @@ end
 #
 #  parent_id   :integer          not null
 #  parent_type :string(50)       not null
-#  ip          :integer          not null
 #  viewed_at   :date             not null
 #  user_id     :integer
+#  ip_address  :string           not null
 #
 # Indexes
 #

db/migrate/20130625022454_change_ip_to_inet_in_views.rb

@@ -0,0 +1,22 @@
+require 'ipaddr'
+
+class ChangeIpToInetInViews < ActiveRecord::Migration
+  def up
+    table = :views
+    add_column table, :ip_address, :inet
+
+    execute "UPDATE views SET ip_address = inet(
+      (ip >> 24 & 255) || '.' ||
+      (ip >> 16 & 255) || '.' ||
+      (ip >>  8 & 255) || '.' ||
+      (ip >>  0 & 255)
+    );"
+
+    change_column table, :ip_address, :inet, { :null => false }
+    remove_column table, :ip
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end

spec/models/view_spec.rb

@@ -6,7 +6,7 @@ describe View do
   it { should belong_to :user }
   it { should validate_presence_of :parent_type }
   it { should validate_presence_of :parent_id }
-  it { should validate_presence_of :ip }
+  it { should validate_presence_of :ip_address }
   it { should validate_presence_of :viewed_at }