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rails--rails/railties/lib/rails/configuration.rb
Genadi Samokovarov 40fc1651ad Delayed middleware delete does not allow move operations
While trying to fix #16433, we made the middleware deletions always
happen at the end. While this works for the case of deleting the
Rack::Runtime middleware, it makes operations like the following
misbehave.

```ruby
gem "bundler", "< 1.16"

begin
  require "bundler/inline"
rescue LoadError => e
  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
  raise e
end

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  gem "rails", github: "rails/rails"
end

require "action_controller/railtie"

class TestApp < Rails::Application
  config.root = __dir__
  secrets.secret_key_base = "secret_key_base"

  config.logger = Logger.new($stdout)
  Rails.logger  = config.logger

  middleware.insert_after ActionDispatch::Session::CookieStore, ::Rails::Rack::Logger, config.log_tags
  middleware.delete ::Rails::Rack::Logger
end

require "minitest/autorun"
require "rack/test"

class BugTest < Minitest::Test
  include Rack::Test::Methods

  def test_returns_success
    get "/"
    assert last_response.ok?
  end

  private
    def app
      Rails.application
    end
end
```

In the case ☝️  the ::Rails::Rack::Logger would be deleted instead of
moved, because the order of middleware stack building execution will be:

```ruby
[:insert, ActionDispatch::Session::CookieStore, [::Rails::Rack::Logger]]
[:delete, ::Rails::Rack::Logger, [config.log_tags]]
```

This is pretty surprising and hard to reason about behaviour, unless you
go spelunking into the Rails configuration code.

I have a few solutions in mind and all of them have their drawbacks.

1. Introduce a `Rails::Configuration::MiddlewareStackProxy#delete!` that
delays the deleted operations. This will make `#delete` to be executed
in order. The drawback here is backwards incompatible behavior and a new
public method.

2. Just revert to the old operations. This won't allow people to delete
the `Rack::Runtime` middleware.

3. Legitimize the middleware moving with the new `#move_after` and
`#move_before` methods. This does not breaks any backwards
compatibility, but includes 2 new methods to the middleware stack.

I have implemented `3.` in this pull request.

Happy holidays! 🎄
2020-01-08 11:30:02 +02:00

161 lines
5.2 KiB
Ruby

# frozen_string_literal: true
require "active_support/ordered_options"
require "active_support/core_ext/object"
require "rails/paths"
require "rails/rack"
module Rails
module Configuration
# MiddlewareStackProxy is a proxy for the Rails middleware stack that allows
# you to configure middlewares in your application. It works basically as a
# command recorder, saving each command to be applied after initialization
# over the default middleware stack, so you can add, swap, or remove any
# middleware in Rails.
#
# You can add your own middlewares by using the +config.middleware.use+ method:
#
# config.middleware.use Magical::Unicorns
#
# This will put the <tt>Magical::Unicorns</tt> middleware on the end of the stack.
# You can use +insert_before+ if you wish to add a middleware before another:
#
# config.middleware.insert_before Rack::Head, Magical::Unicorns
#
# There's also +insert_after+ which will insert a middleware after another:
#
# config.middleware.insert_after Rack::Head, Magical::Unicorns
#
# Middlewares can also be completely swapped out and replaced with others:
#
# config.middleware.swap ActionDispatch::Flash, Magical::Unicorns
#
# Middlewares can be moved from one place to another:
#
# config.middleware.move_before ActionDispatch::Flash, Magical::Unicorns
#
# This will move the <tt>Magical::Unicorns</tt> middleware before the
# <tt>ActionDispatch::Flash</tt>. You can also move it after:
#
# config.middleware.move_after ActionDispatch::Flash, Magical::Unicorns
#
# And finally they can also be removed from the stack completely:
#
# config.middleware.delete ActionDispatch::Flash
#
class MiddlewareStackProxy
def initialize(operations = [], delete_operations = [])
@operations = operations
@delete_operations = delete_operations
end
def insert_before(*args, &block)
@operations << -> middleware { middleware.send(__method__, *args, &block) }
end
ruby2_keywords(:insert_before) if respond_to?(:ruby2_keywords, true)
alias :insert :insert_before
def insert_after(*args, &block)
@operations << -> middleware { middleware.send(__method__, *args, &block) }
end
ruby2_keywords(:insert_after) if respond_to?(:ruby2_keywords, true)
def swap(*args, &block)
@operations << -> middleware { middleware.send(__method__, *args, &block) }
end
ruby2_keywords(:swap) if respond_to?(:ruby2_keywords, true)
def use(*args, &block)
@operations << -> middleware { middleware.send(__method__, *args, &block) }
end
ruby2_keywords(:use) if respond_to?(:ruby2_keywords, true)
def delete(*args, &block)
@delete_operations << -> middleware { middleware.send(__method__, *args, &block) }
end
def move_before(*args, &block)
@delete_operations << -> middleware { middleware.send(__method__, *args, &block) }
end
alias :move :move_before
def move_after(*args, &block)
@delete_operations << -> middleware { middleware.send(__method__, *args, &block) }
end
def unshift(*args, &block)
@operations << -> middleware { middleware.send(__method__, *args, &block) }
end
ruby2_keywords(:unshift) if respond_to?(:ruby2_keywords, true)
def merge_into(other) #:nodoc:
(@operations + @delete_operations).each do |operation|
operation.call(other)
end
other
end
def +(other) # :nodoc:
MiddlewareStackProxy.new(@operations + other.operations, @delete_operations + other.delete_operations)
end
protected
attr_reader :operations, :delete_operations
end
class Generators #:nodoc:
attr_accessor :aliases, :options, :templates, :fallbacks, :colorize_logging, :api_only
attr_reader :hidden_namespaces
def initialize
@aliases = Hash.new { |h, k| h[k] = {} }
@options = Hash.new { |h, k| h[k] = {} }
@fallbacks = {}
@templates = []
@colorize_logging = true
@api_only = false
@hidden_namespaces = []
end
def initialize_copy(source)
@aliases = @aliases.deep_dup
@options = @options.deep_dup
@fallbacks = @fallbacks.deep_dup
@templates = @templates.dup
end
def hide_namespace(namespace)
@hidden_namespaces << namespace
end
def method_missing(method, *args)
method = method.to_s.sub(/=$/, "").to_sym
if args.empty?
if method == :rails
return @options[method]
else
return @options[:rails][method]
end
end
if method == :rails || args.first.is_a?(Hash)
namespace, configuration = method, args.shift
else
namespace, configuration = args.shift, args.shift
namespace = namespace.to_sym if namespace.respond_to?(:to_sym)
@options[:rails][method] = namespace
end
if configuration
aliases = configuration.delete(:aliases)
@aliases[namespace].merge!(aliases) if aliases
@options[namespace].merge!(configuration)
end
end
end
end
end