Class: Rack::Builder

Rack::Builder implements a small DSL to iteratively construct Rack applications.

Example:

 app = Rack::Builder.new {
   use Rack::CommonLogger
   use Rack::ShowExceptions
   map "/lobster" do
     use Rack::Lint
     run Rack::Lobster.new
   end
 }

use adds a middleware to the stack, run dispatches to an application. You can use map to construct a Rack::URLMap in a convenient way.

Methods

call map new run to_app use

Public Class methods

new(&block)

[Source]

    # File lib/rack/builder.rb, line 20
20:     def initialize(&block)
21:       @ins = []
22:       instance_eval(&block)
23:     end

Public Instance methods

call(env)

[Source]

    # File lib/rack/builder.rb, line 48
48:     def call(env)
49:       to_app.call(env)
50:     end

map(path, &block)

[Source]

    # File lib/rack/builder.rb, line 33
33:     def map(path, &block)
34:       if @ins.last.kind_of? Hash
35:         @ins.last[path] = Rack::Builder.new(&block).to_app
36:       else
37:         @ins << {}
38:         map(path, &block)
39:       end
40:     end

run(app)

[Source]

    # File lib/rack/builder.rb, line 29
29:     def run(app)
30:       @ins << app #lambda { |nothing| app }
31:     end

to_app()

[Source]

    # File lib/rack/builder.rb, line 42
42:     def to_app
43:       @ins[-1] = Rack::URLMap.new(@ins.last)  if Hash === @ins.last
44:       inner_app = @ins.pop
45:       @ins.reverse.inject(inner_app) { |a, e| e.call(a) }
46:     end

use(middleware, *args)

[Source]

    # File lib/rack/builder.rb, line 25
25:     def use(middleware, *args)
26:       @ins << lambda { |app| middleware.new(app, *args) }
27:     end