Middleware

Middleware

Middleware are implemented as classes. Middleware class inherits from Base::Middleware (or, just type Middleware if you prefer require amethyst/all), and should have the call method, and return an Amethyst::Http::Response. (usually, by calling next midleware in MiddlewareStack with @app.call(request))

def call(request)
  # do something
  response = @app.call(request) # here response came from 'upper' middleware
  # do something
  response # return response down to the stack
end

Here is an example of middleware that calculates time elapsed between request and response.

class TimeLogger < Middleware::Base

  # This one will be called when app gets request. It accepts Http::Request
  def call(request)
    t_req    = Time.now
    response = @app.call(request) # sends request to next middleware
    t_res    = Time.now
    elapsed  = (t_res - t_req).to_f*1000
    string   = "%.4f ms" % elapsed
    response.body += "<hr>"+string
    response
  end
end