Working implementation

README.md

@@ -41,6 +41,14 @@ ActiveRecord::Schema.define(version: 20161122225732) do
 end
 ```
 
+Define it in your model
+
+```
+class Worker < ActiveRecord::Base
+  attribute :job_uuid, :uuid
+end
+```
+
 Then use as regular string column, except that it will be stored in a 16 bytes binary column.
 
 ## Development

activerecord-mysql-uuid-column.gemspec

@@ -26,6 +26,6 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "rspec", "~> 3.0"
   spec.add_development_dependency "byebug", '~> 0'
   spec.add_development_dependency "looksee", '~> 0'
-  spec.add_dependency "activerecord", ">= 4.2.5", "< 6"
-  spec.add_dependency "mysql2", "~> 0.4.0"
+  spec.add_dependency "activerecord", ">= 5", "< 6"
+  spec.add_dependency "mysql2", "~> 0.4.4"
 end

lib/active_record-mysql-uuid_column.rb

@@ -1,28 +1,8 @@
-require "active_record-mysql-uuid_column/version"
 require 'active_record'
+require 'active_record/connection_adapters/mysql2_adapter'
+require 'active_record-mysql-uuid_column/version'
+require 'active_record-mysql-uuid_column/migration_column.rb'
+require 'active_record-mysql-uuid_column/type_class.rb'
+require 'active_record-mysql-uuid_column/mysql2_adapter_monkey_patch.rb'
 
-module ActiveModel
-  module Type
-    class Uuid
-      def method_missing(name)
-        debugger
-        puts "whatever"
-      end
-    end
-  end
-end
-module ActiveRecord
-  module ConnectionAdapters
-    module MySQL
-      module ColumnMethods
-        def uuid(*args, **options)
-          # http://dba.stackexchange.com/questions/904/mysql-data-type-for-128-bit-integers
-          # http://dev.mysql.com/doc/refman/5.7/en/binary-varbinary.html
-          args.each { |name| column(name, :binary, options.merge(limit: 16)) }
-        end
-      end
-    end
-
-  end
-end
-
+ActiveRecord::Type.register(:uuid, ActiveRecord::Type::Uuid, adapter: :mysql2)

lib/active_record-mysql-uuid_column/migration_column.rb

@@ -0,0 +1,13 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module MySQL
+      module ColumnMethods
+        def uuid(*args, **options)
+          # http://dba.stackexchange.com/questions/904/mysql-data-type-for-128-bit-integers
+          # http://dev.mysql.com/doc/refman/5.7/en/binary-varbinary.html
+          args.each { |name| column(name, :binary, options.merge(limit: 16)) }
+        end
+      end
+    end
+  end
+end

lib/active_record-mysql-uuid_column/mysql2_adapter_monkey_patch.rb

@@ -0,0 +1,15 @@
+module ActiveRecord
+  module ConnectionAdapters
+    class Mysql2Adapter
+      private
+
+      def _quote(value)
+        if value.is_a?(Type::Uuid::Data) or value.is_a?(Type::Binary::Data)
+          "x'#{value.hex}'"
+        else
+          super
+        end
+      end
+    end
+  end
+end

lib/active_record-mysql-uuid_column/type_class.rb

@@ -0,0 +1,78 @@
+module ActiveRecord
+  module Type
+    class Uuid < ActiveRecord::Type::Binary
+      def type
+        :uuid
+      end
+
+      # from database binary(16) to string
+      def deserialize(value)
+        return nil if value.nil?
+        Data.from_database(value)
+      end
+
+      # from user input (string) to database
+      def cast(value)
+        if value.is_a?(Data)
+          value
+        elsif value.is_a?(ActiveSupport::ToJsonWithActiveSupportEncoder) or value.is_a?(String)
+          Data.from_uuid_string(super)
+        else
+          raise ArgumentError,
+            "Unsupported input data of class type #{value.class}"
+        end
+      end
+
+      def serialize(value)
+        value
+      end
+
+      def assert_valid_value(value)
+        case value.class
+        when String, ActiveSupport::ToJsonWithActiveSupportEncoder
+          if value.downcase.gsub(/[^a-f0-9]/, '').size == 32
+            value
+          else
+            raise SerializationTypeMismatch,
+              "Invalid String uuid #{value}."
+          end
+        else
+          raise SerializationTypeMismatch,
+            "Unsupported value object of type #{value.class}."
+        end
+      end
+
+      class Data
+        def initialize(display_format, storage_format)
+          @display_format, @storage_format = display_format, storage_format
+        end
+
+        def self.from_uuid_string(uuid)
+          new(uuid, uuid.downcase.gsub(/[^a-f0-9]/, ''))
+        end
+
+        def self.from_database(value)
+          storage_format = value.unpack('H*').first.rjust(32, '0')
+          new(
+            storage_format.gsub(/^(.{8})(.{4})(.{4})(.{4})(.{12})$/, '\1-\2-\3-\4-\5'),
+            storage_format
+          )
+        end
+
+        def to_s
+          @display_format
+        end
+        alias_method :to_str, :to_s
+
+        def hex
+          @storage_format
+        end
+
+        def ==(other)
+          other == to_s || super
+        end
+      end
+
+    end
+  end
+end

spec/mysql_uuid_column_spec.rb

@@ -1,8 +1,7 @@
 require "spec_helper"
-require 'byebug'
-require 'looksee'
 
 class TestUuid < ActiveRecord::Base
+  attribute :uuid, :uuid
 end
 
 describe ActiveRecord::Mysql::UuidColumn do