Mandrake

Mandrake loads middlewares conditionally, and it provides two options and DSL for setting conditions. If you use Mandrake, you can avoid executing unnecessary middlewares by setting conditions.

Add this line to your application's Gemfile:

gem 'mandrake'

And then execute:

$ bundle

Or install it yourself as:

$ gem install mandrake

Mandrake provides :if and :unless options which are available on #use method. These options can be used to set the condition to enable the middleware at runtime.

Mandrake::Builder.new do
  use Rack::Deflate, if:     request.path_info.start_with?("/deflater")
  use Rack::ETag,    unless: request.path_info.end_with?("etag")
  run ->(env){ [200, {'Content-Type' => 'text/plain'}, ["Hello World"]] }
end

Mandrake provides env and request methods for building the conditional expression. They can be used in the block.

Mandrake::Builder.new do
  request.path_info.start_with?("/public") #=> 'request.path_info.start_with?("/public")'
  env["PATH_INFO"] == "/public" #=> 'env["PATH_INFO"] == "/public"'
end

If you want to use these without the block executed on initialization, you must pass the proc to the conditional options.

builder = Mandrake::Builder.new
builder.use Rack::Deflater, if: proc{ request.path_info.start_with?("/public") }

The arguments of these options allow to pass the lambda, but its behavior is different from proc. lambda is defined as the validation method by define_method. Therefore the validation method will be slow.

Mandrake::Builder.new do
  use Rack::Deflate, if: proc{ request.path_info.start_with?("/deflater") }
  run ->(env){ [200, {'Content-Type' => 'text/plain'}, ["Hello World"]] }
end

In the end, Mandrake::Builder inherits Rack::Builder, so you can use this like Rack::Builder basically. Of course, it does not break the compatibility.

This class is for incorporating mandrake into your application easily. You can use as well as the Rack Middleware.

use Mandrake::Middleware do
  use Rack::Deflate, if:     request.path_info.start_with?("/deflater")
  use Rack::ETag,    unless: request.path_info.end_with?("etag")
end

1. Fork it ( https://github.com/namusyaka/mandrake/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request