删除 Rails 3中的 ActiveRecord

既然 Rails 3测试版已经发布了，我想我应该重写一下我刚开始编写的 Rails 3测试版的应用程序，这样既可以感受一下，又可以提前一些。该应用程序的所有模型都使用 MongoDB 和 MongoMapper，因此不需要 ActiveRecord。在前一个版本中，我通过以下方式卸载 activerrecord:

config.frameworks -= [ :active_record ]    # inside environment.rb

在最新版本中，这种方法不起作用——它只是抛出一个错误:

/Library/Ruby/Gems/1.8/gems/railties-3.0.0.beta/lib/rails/configuration.rb:126:in
`frameworks': config.frameworks in no longer supported. See the generated
config/boot.rb for steps on how to limit the frameworks that will be loaded
(RuntimeError)
from *snip*

当然，我已经按照建议查看了 boot.rb，但就我所知，这里没有关于如何卸载 AR 的线索。我需要这样做的原因不仅是因为装载我不想要的东西是愚蠢的，而且它抱怨它无法建立一个 DB 连接，即使我尝试为控制器运行一个生成器。这是因为我清除了 database.yml，并将其替换为 MongoDB 的连接详细信息，以便使用 这个要点来使用 datase.yml 来处理 MongoDB 的连接详细信息。不知道为什么它需要能够启动一个 DB 连接，只是为了生成一个控制器..。

有人知道正确的 Rails 3做这件事的方法吗？

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最佳答案

I'm going by this from reading the source, so let me know if it actually worked. :)

The rails command that generates the application template now has an option -O, which tells it to skip ActiveRecord.

If you don't feel like rerunning rails, you should check the following in your existing app:

  • Check that your config/application.rb doesn't have require 'rails/all' or require "active_record/railtie". Instead, for a standard Rails setup without ActiveRecord, it should have only the following requires:

    require File.expand_path('../boot', __FILE__)


require "action_controller/railtie"
require "action_mailer/railtie"
require "active_resource/railtie"
require "rails/test_unit/railtie"
require "sprockets/railtie"


# Auto-require default libraries and those for the current Rails environment.
Bundler.require :default, Rails.env

  • If, in config/application.rb, you are using the config.generators section, make sure it doesn't have the line g.orm :active_record. You can set this explicitly to nil, if you want, but this should be the default when g.orm is completely omitted.

  • Optional, but in your Gemfile, remove the gem line that loads the module for your database. This could be the line gem "mysql" for example.

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All of the above are true. The one more thing which I had to do in rails 3.1 is to comment out 

config.active_record.identity_map = true

in config/application.rb.

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For a new rails app, you can have it exclude active record by specifying the --skip-active-record parameter. Eg:

rails new appname --skip-active-record
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If you generated a new project using Rails 3.2, you will also need to comment out:

config.active_record.mass_assignment_sanitizer = :strict

and

config.active_record.auto_explain_threshold_in_seconds = 0.5

in your development.rb file.

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Also comment out

# config/application.rb
config.active_record.whitelist_attributes = true

(noted on rails 3.2.13)

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If you're running rspec, you also need to remove (in spec_helper):

  # Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
config.fixture_path = "#{::Rails.root}/spec/fixtures"

and remove

  # If you're not using ActiveRecord, or you'd prefer not to run each of your
# examples within a transaction, remove the following line or assign false
# instead of true.
config.use_transactional_fixtures = true
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Rails 4

I was looking for how to disable it in rails 4 and only found this answer which no longer works in rails 4. So this is how you can do it in rails 4 (tested in RC1).

In a new project

rails new YourProject --skip-active-record

In an existing project

  • In your Gemfile, remove the database driver gem, e.g. gem 'sqlite3' or gem 'pg'.

  • In config/application.rb, replace require 'rails/all' with 

    require "action_controller/railtie"
require "action_mailer/railtie"
require "sprockets/railtie"
require "rails/test_unit/railtie"

  • In config/environments/development.rb, remove or comment out config.active_record.migration_error = :page_load

  • Potentially you have to remove active_record helpers from the spec_helper (via VenoM in the comments)

  • Potentially you have to remove the ConnectionManagement middleware (seems to be the case with unicorn): config.app_middleware.delete "ActiveRecord::ConnectionAdapters::ConnectionManagement" (via https://stackoverflow.com/a/18087332/764342)

I hope this helps others looking for how to disable ActiveRecord in Rails 4.


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