Merge pull request #8 from saveriomiroddi/native_json_data_type_support

Add native JSON data type support, through a new adapter

Author: 64kramsystem

.rubocop_todo.yml

@@ -1,22 +1,37 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2018-02-12 18:54:36 +0100 using RuboCop version 0.52.1.
+# on 2018-02-12 18:57:06 +0100 using RuboCop version 0.52.1.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 4
+# Offense count: 5
 Style/Documentation:
   Exclude:
     - 'spec/**/*'
     - 'test/**/*'
-    - 'lib/active_record/connection_adapters/schema_definitions.rb'
+    - 'lib/active_record/connection_adapters/abstract/json_schema_definitions.rb'
+    - 'lib/active_record/connection_adapters/mysql2_json_adapter.rb'
     - 'lib/active_record/type/json.rb'
-    - 'lib/json_on_rails.rb'
 
-# Offense count: 1
+# Offense count: 2
 # Configuration parameters: MinBodyLength.
 Style/GuardClause:
   Exclude:
+    - 'lib/active_record/connection_adapters/mysql2_json_adapter.rb'
     - 'lib/active_record/type/json.rb'
+
+# Offense count: 1
+# Cop supports --auto-correct.
+Style/IfUnlessModifier:
+  Exclude:
+    - 'lib/active_record/connection_adapters/mysql2_json_adapter.rb'
+
+# Offense count: 1
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle, AllowInnerSlashes.
+# SupportedStyles: slashes, percent_r, mixed
+Style/RegexpLiteral:
+  Exclude:
+    - 'lib/active_record/connection_adapters/mysql2_json_adapter.rb'

README.md

@@ -31,6 +31,13 @@ that's all!
 
 ## Usage/example
 
+Change the `mysql` connection adapter to `mysql2_json`, in `config/database.yml`:
+
+```yaml
+default: &default
+  adapter: mysql2_json
+```
+
 Create a table:
 
 ```
@@ -54,13 +61,10 @@ class CreateUsers < ActiveRecord::Migration
 end
 ```
 
-define the model:
+define the model (rails will automatically pick up the data type):
 
 ```
-class User < ActiveRecord::Base
-  attribute :extras, ActiveRecord::Type::Json.new
-end
-
+class User < ActiveRecord::Base; end
 ```
 
 then (ab)use the new attribute!:
@@ -71,6 +75,22 @@ User.create!(login: "saverio", extras: {"uses" => ["mysql", "json"]})
 User.last.extras.fetch("uses") # => ["mysql", "json"]
 ```
 
+The schema can be dumped as usual; json columns will be transparently included:
+
+```sh
+$ rake db:schema:dump
+$ cat db/schema.rb
+ActiveRecord::Schema.define(version: 0) do
+
+  create_table "users", force: :cascade do |t|
+    t.json   "extras"
+  end
+
+end
+```
+
+## Caveat/further documentation
+
 Don't forget that JSON doesn't support symbols, therefore, they can be set, but are accessed/loaded as strings.
 
 Users are encouraged to have a look at the test suite ([here](spec/json_on_rails/json_attributes_spec.rb) and [here](spec/json_on_rails/arel_methods_spec.rb)) for an exhaustive view of the functionality.

lib/active_record/connection_adapters/schema_definitions.rb renamed to lib/active_record/connection_adapters/abstract/json_schema_definitions.rb

@@ -1,3 +1,7 @@
+# frozen_string_literal: true
+
+require "active_record/connection_adapters/abstract/schema_definitions"
+
 module ActiveRecord
   # Unfortunately, the type shorthands are hardcoded, and the code itself is not encapsulated
   # in a method, so there's not much design freedom.

lib/active_record/connection_adapters/mysql2_json_adapter.rb

@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+require "active_record/connection_adapters/mysql2_adapter"
+require "active_record/type/json"
+
+# ActiveRecord resources:
+#
+#     lib/active_record/connection_adapters/mysql2_adapter.rb
+#     lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+#     lib/active_record/schema_dumper.rb
+#
+# and a few other files.
+#
+module ActiveRecord
+  module ConnectionHandling
+    def mysql2_json_connection(config)
+      config = config.symbolize_keys
+
+      config[:username] = "root" if config[:username].nil?
+
+      if Mysql2::Client.const_defined? :FOUND_ROWS
+        config[:flags] = Mysql2::Client::FOUND_ROWS
+      end
+
+      client = Mysql2::Client.new(config)
+      options = [config[:host], config[:username], config[:password], config[:database], config[:port], config[:socket], 0]
+      ConnectionAdapters::Mysql2JsonAdapter.new(client, logger, options, config)
+    rescue Mysql2::Error => error
+      if error.message.include?("Unknown database")
+        raise ActiveRecord::NoDatabaseError.new(error.message, error)
+      else
+        raise
+      end
+    end
+  end
+end
+
+module ActiveRecord
+  module ConnectionAdapters
+    class Mysql2JsonAdapter < Mysql2Adapter
+      ADAPTER_NAME = "Mysql2Json".freeze
+
+      def native_database_types
+        super.merge(json: {name: "json"})
+      end
+
+      protected
+
+      def initialize_type_map(m)
+        super
+
+        m.register_type %r{json}i, Type::Json.new
+      end
+    end
+  end
+end

lib/active_record/type/json.rb

@@ -1,10 +1,10 @@
 # frozen_string_literal: true
 
-# Resources:
+# ActiveRecord resources:
 #
-#     gems/activerecord-4.<version>/lib/active_record/attributes.rb
-#     gems/activerecord-4.<version>/lib/active_record/type/value.rb
-#     gems/activerecord-4.<version>/lib/active_record/type/mutable.rb
+#     lib/active_record/attributes.rb
+#     lib/active_record/type/value.rb
+#     lib/active_record/type/mutable.rb
 #
 module ActiveRecord
   module Type

lib/json_on_rails.rb

@@ -1,6 +1,4 @@
 # frozen_string_literal: true
 
-require_relative "active_record/type/json"
-require_relative "active_record/connection_adapters/schema_definitions"
-
-module JsonOnRails; end
+require_relative "active_record/connection_adapters/abstract/json_schema_definitions"
+require_relative "active_record/connection_adapters/mysql2_json_adapter"

spec/json_on_rails/arel_methods_spec.rb

@@ -19,8 +19,8 @@
       expect(found_user).to eql(user)
     end
 
-    # WATCH OUT! The semantic of passing an Array/Hash in Rails is not what one would think it
-    # would for a JSON data type. This is independent of this gem.
+    # WATCH OUT! AREL finders are (appropriately) not overloaded. In order to perform JSON-specific
+    # comparisons, use the MySQL operators (see above).
     #
     context "passing collection objects" do
       it "should not find the instance, when searching an empty hash instance" do
@@ -29,12 +29,10 @@
         expect(found_user).to be(nil)
       end
 
-      it "should not find the instance, when searching an array instance" do
-        user.update_attributes!(extras: [1, 2, 3])
+      it "should raise an error, when searching an array instance" do
+        error_message = "Invalid data type for JSON serialization: #{1.class} (only Hash/Array/nil supported)"
 
-        found_user = User.find_by(extras: [1, 2, 3])
-
-        expect(found_user).to be(nil)
+        expect { User.find_by(extras: [1, 2, 3]) }.to raise_error(ArgumentError, error_message)
       end
     end
   end

spec/json_on_rails/schema_dump_spec.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+describe "Schema dump" do
+  it "should support the json data type" do
+    output = ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, StringIO.new)
+
+    expect(output.string).to match(/t.json "extras"/)
+  end
+end

spec/setup/config/database.yml

@@ -1,4 +1,4 @@
-adapter: mysql2
+adapter: mysql2_json
 encoding: utf8
 database: json_on_rails_test
 socket: <%= ENV.fetch("MYSQL_SOCKET", "/var/run/mysqld/mysqld.sock") %>

spec/setup/models/user.rb

@@ -1,5 +1,3 @@
 # frozen_string_literal: true
 
-class User < ActiveRecord::Base
-  attribute :extras, ActiveRecord::Type::Json.new
-end
+class User < ActiveRecord::Base; end