rails middleware

app.middleware.insert(0, Rack::MiniProfiler)

   class FooMiddleware
        def initialize(app)
            puts "init foo"
            @app = app
        end

        def call(env)
            puts "foo"
            result = @app.call(env)
            puts "finish foo"
            return result
        end
    end

    class BarMiddleware
        def initialize(app)
            puts "init bar"
            @app = app
        end

        def call(env)
            puts "bar"
            result = @app.call(env)
            puts "finish bar"
            return result
        end
    end

    class BazMiddleware
        def initialize(app)
            puts "init baz"
            @app = app
        end

        def call(env)
            puts "baz"
            result = @app.call(env)
            puts "finish baz"
            return result
        end
    end

    config.middleware.use FooMiddleware

    config.middleware.use BarMiddleware

    config.middleware.use BazMiddleware

foo
bar
baz
finish baz
finish bar
finish foo