Restore MultiJson and add custom option modules. Fix #303

In order to support JRuby it'd be better not force installing Oj since
it cannot be used in JRuby if C extensions are not enabled, and they are
not supported by default.

So, we add MultiJson again to the project. This will create more
different scenarios but since it could be the best option according to
previous paragraph.

We've added in this change support for custom options depending on the
loaded adapter in MultiJson. We can add more adapter options modules in
this way:

module Rollbar
  module JSON
    module AnyMultiJsonAdapterName
      def self.options
        { # here comes the options we need for that adapter }
      end
    end
  end
end

We have, for now, just the Oj module that will return the options we had
before this commit.

The specs run with Oj by default and it's the recommended adapter to use
with Rollbar.

lib/rollbar.rb

@@ -740,17 +740,12 @@ def configure
 
       yield(configuration)
 
-      configure_json_backend
       require_hooks
       require_core_extensions
 
       reset_notifier!
     end
 
-    def configure_json_backend
-      Rollbar::JSON.setup
-    end
-
     def reconfigure
       @configuration = Configuration.new
       @configuration.enabled = true

lib/rollbar/json.rb

@@ -1,37 +1,47 @@
+require 'rollbar/json/oj'
+require 'rollbar/json/default'
+
 module Rollbar
   module JSON
     extend self
 
-    attr_accessor :backend_name
-    attr_accessor :dump_method
-    attr_accessor :load_method
-
-    def load_oj
-      require 'oj'
+    attr_writer :adapter_module
 
-      options = { :mode=> :compat,
-                  :use_to_json => false,
-                  :symbol_keys => false,
-                  :circular => false
-                }
+    def dump(object)
+      MultiJson.dump(object, adapter_options)
+    end
 
-      self.dump_method = proc { |obj| Oj.dump(obj, options) }
-      self.load_method = proc { |obj| Oj.load(obj, options) }
-      self.backend_name = :oj
+    def load(string)
+      MultiJson.load(string, adapter_options)
+    end
 
-      true
+    def adapter_options
+      adapter_module.options
     end
 
-    def dump(object)
-      dump_method.call(object)
+    def adapter_module
+      @adapter_module ||= find_adapter_module
     end
 
-    def load(string)
-      load_method.call(string)
+    def find_adapter_module
+      module_name = multi_json_adapter_module
+
+      begin
+        const_get(module_name)
+      rescue NameError
+        Default
+      end
     end
 
-    def setup
-      load_oj
+    # MultiJson adapters have this name structure:
+    # "MultiJson::Adapters::{AdapterModule}"
+    #
+    # Ex: MultiJson::Adapters::Oj
+    # Ex: MultiJson::Adapters::JsonGem
+    #
+    # In this method we just get the last module name.
+    def multi_json_adapter_module
+      MultiJson.current_adapter.name[/^MultiJson::Adapters::(.*)$/, 1]
     end
   end
 end

lib/rollbar/json/default.rb

@@ -0,0 +1,11 @@
+module Rollbar
+  module JSON
+    module Default
+      extend self
+
+      def options
+        {}
+      end
+    end
+  end
+end

lib/rollbar/json/oj.rb

@@ -0,0 +1,15 @@
+module Rollbar
+  module JSON
+    module Oj
+      extend self
+
+      def options
+        { :mode=> :compat,
+          :use_to_json => false,
+          :symbol_keys => false,
+          :circular => false
+        }
+      end
+    end
+  end
+end

rollbar.gemspec

@@ -28,5 +28,6 @@ Gem::Specification.new do |gem|
   gem.add_development_dependency 'delayed_job'
   gem.add_development_dependency 'rake', '>= 0.9.0'
   gem.add_development_dependency 'redis'
-  gem.add_runtime_dependency     'oj', '~> 2.12.14'
+  gem.add_runtime_dependency     'multi_json'
+  gem.add_development_dependency 'oj', '~> 2.12.14'
 end

spec/delayed/backend/test.rb

@@ -38,7 +38,7 @@ def initialize(hash = {})
           self.attempts = 0
           self.priority = 0
           self.id = (self.class.id += 1)
-          hash.each { |k, v| send(:"#{k}=", v) }
+          hash.each { |k, v| send("#{k}=", v) }
         end
 
         def self.all

spec/rollbar/json/oj_spec.rb

@@ -0,0 +1,18 @@
+require 'spec_helper'
+
+require 'rollbar/json/oj'
+
+describe Rollbar::JSON::Oj do
+  let(:options) do
+    {
+      :mode => :compat,
+      :use_to_json => false,
+      :symbol_keys => false,
+      :circular => false
+    }
+  end
+
+  it 'returns correct options' do
+    expect(described_class.options).to be_eql(options)
+  end
+end

spec/rollbar/json_spec.rb

@@ -1,43 +1,89 @@
 require 'spec_helper'
+
+require 'multi_json'
 require 'rollbar/json'
 require 'rollbar/configuration'
 
-describe Rollbar::JSON do
-  before do
-    Rollbar::JSON.setup
+class Rollbar::JSON::MockAdapter
+  def self.options
+    { 'mock' => 'adapter' }
   end
+end
 
-  let(:payload) do
-    { :foo => :bar }
+module MultiJson
+  module Adapters
+    module MockAdapter
+    end
   end
+end
 
-  let(:options) do
-    {
-      :mode => :compat,
-      :use_to_json => false,
-      :symbol_keys => false,
-      :circular => false
-    }
+module MultiJson
+  module Adapters
+    module MissingCustomOptions
+    end
+  end
+end
+
+
+describe Rollbar::JSON do
+  let(:payload) do
+    { :foo => :bar }
   end
+  let(:adapter_options) { { 'option' => 'value' } }
 
   describe '.dump' do
-    it 'has JSON as backend' do
-      expect(Rollbar::JSON.backend_name).to be_eql(:oj)
+    before do
+      allow(described_class).to receive(:adapter_options).and_return(adapter_options)
     end
 
+    it 'calls MultiJson.dump' do
+      expect(::MultiJson).to receive(:dump).once.with(payload, adapter_options)
 
-    it 'calls JSON.generate' do
-      expect(::Oj).to receive(:dump).once.with(payload, options)
-
-      Rollbar::JSON.dump(payload)
+      described_class.dump(payload)
     end
   end
 
   describe '.load' do
+    before do
+      allow(described_class).to receive(:adapter_options).and_return(adapter_options)
+    end
+
     it 'calls MultiJson.load' do
-      expect(::Oj).to receive(:load).once.with(payload, options)
+      expect(::MultiJson).to receive(:load).once.with(payload, adapter_options)
+
+      described_class.load(payload)
+    end
+  end
+
+  describe '.adapter_options' do
+    it 'calls .options in adapter module' do
+      expect(described_class.adapter_module).to receive(:options)
+
+      described_class.adapter_options
+    end
+  end
+
+  describe '.adapter_module' do
+    before { described_class.adapter_module = nil }
+
+    context 'with a defined rollbar adapter' do
+      let(:expected_adapter) { Rollbar::JSON::MockAdapter }
+
+      it 'returns the correct options' do
+        MultiJson.with_adapter(MultiJson::Adapters::MockAdapter) do
+          expect(described_class.adapter_module).to be(expected_adapter)
+        end
+      end
+    end
+
+    context 'without a defined rollbar adapter' do
+      let(:expected_adapter) { Rollbar::JSON::Default }
 
-      Rollbar::JSON.load(payload)
+      it 'returns the correct options' do
+        MultiJson.with_adapter(MultiJson::Adapters::MissingCustomOptions) do
+          expect(described_class.adapter_module).to be(expected_adapter)
+        end
+      end
     end
   end
 end

spec/spec_helper.rb

@@ -5,6 +5,10 @@
 require 'rspec/rails'
 require 'database_cleaner'
 require 'genspec'
+require 'multi_json'
+require 'oj'
+
+MultiJson.use(:oj)
 
 namespace :dummy do
   load 'spec/dummyapp/Rakefile'