Controllers

Route Filters

Before filters are evaluated before each request within the context of the request and can modify the request and response. Instance variables set in filters are accessible by routes and templates:

before do
  @note = 'Hi!'
end

After filters are evaluated after each request within the context of the request and can also modify the request and response. Instance variables set in before filters and routes are accessible by after filters:

after do
  puts @note
end

This is now standard in Sinatra, but Padrino adds support for filters being scoped by controller which means that unlike Sinatra in which a filter is global, in Padrino you can run different filters for each controller:

Demo::App.controllers :posts do
  before { @foo = "bar" }
  get("/posts") { render :haml, "Has access to @foo variable" }
end

Demo::App.controllers :accounts do
  before { @bar = "foo" }
  get("/accounts") { render :haml, "Has access to @bar variable" }
end

This allows for more fine-grained filters and prevents the need to have unnecessary filters running on every route. As of Padrino 0.10.0, there is also a much more powerful route selection system that has been setup:

Demo::App.controllers :example do
  # Based on a symbol
  before :index do
    # Code here to be executed
  end

  # Based on a symbol, regexp and string all in one
  before :index, /main/, '/example' do
    # Code here to be executed
  end

  # Also filter by excluding an action
  before :except => :index do
    # Code here to be executed
  end

  get :index do
    # ...
  end
end

This gives developers a lot more flexibility when running filters and enables much more selective execution in a convenient way.

last updated: 2022-02-22