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 Magical::Unicorns 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

And finally they can also be removed from the stack completely:

config.middleware.delete ActionDispatch::Flash
Methods
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Attributes
[R] delete_operations
[R] operations
Class Public methods
new(operations = [], delete_operations = [])
# File railties/lib/rails/configuration.rb, line 38
def initialize(operations = [], delete_operations = [])
  @operations = operations
  @delete_operations = delete_operations
end
Instance Public methods
delete(*args, &block)
# File railties/lib/rails/configuration.rb, line 65
def delete(*args, &block)
  @delete_operations << -> middleware { middleware.send(__method__, *args, &block) }
end
insert(*args, &block)
Alias for: insert_before
insert_after(*args, &block)
# File railties/lib/rails/configuration.rb, line 50
def insert_after(*args, &block)
  @operations << -> middleware { middleware.send(__method__, *args, &block) }
end
insert_before(*args, &block)
Also aliased as: insert
# File railties/lib/rails/configuration.rb, line 43
def insert_before(*args, &block)
  @operations << -> middleware { middleware.send(__method__, *args, &block) }
end
swap(*args, &block)
# File railties/lib/rails/configuration.rb, line 55
def swap(*args, &block)
  @operations << -> middleware { middleware.send(__method__, *args, &block) }
end
unshift(*args, &block)
# File railties/lib/rails/configuration.rb, line 69
def unshift(*args, &block)
  @operations << -> middleware { middleware.send(__method__, *args, &block) }
end
use(*args, &block)
# File railties/lib/rails/configuration.rb, line 60
def use(*args, &block)
  @operations << -> middleware { middleware.send(__method__, *args, &block) }
end