aboutsummaryrefslogtreecommitdiffstats
path: root/actionpack/lib/action_dispatch/middleware/stack.rb
blob: bbf734f103566444202f33f26fa5100918788342 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
require "active_support/inflector/methods"
require "active_support/dependencies"

module ActionDispatch
  class MiddlewareStack
    class Middleware
      attr_reader :args, :block, :name, :classcache

      def initialize(klass_or_name, *args, &block)
        @klass = nil

        if klass_or_name.respond_to?(:name)
          @klass = klass_or_name
          @name  = @klass.name
        else
          @name  = klass_or_name.to_s
        end

        @classcache = ActiveSupport::Dependencies::Reference
        @args, @block = args, block
      end

      def klass
        @klass || classcache[@name]
      end

      def ==(middleware)
        case middleware
        when Middleware
          klass == middleware.klass
        when Class
          klass == middleware
        else
          normalize(@name) == normalize(middleware)
        end
      end

      def inspect
        klass.to_s
      end

      def build(app)
        klass.new(app, *args, &block)
      end

    private

      def normalize(object)
        object.to_s.strip.sub(/^::/, '')
      end
    end

    include Enumerable

    attr_accessor :middlewares

    def initialize(*args)
      @middlewares = []
      yield(self) if block_given?
    end

    def each
      @middlewares.each { |x| yield x }
    end

    def size
      middlewares.size
    end

    def last
      middlewares.last
    end

    def [](i)
      middlewares[i]
    end

    def unshift(*args, &block)
      middleware = self.class::Middleware.new(*args, &block)
      middlewares.unshift(middleware)
    end

    def initialize_copy(other)
      self.middlewares = other.middlewares.dup
    end

    def insert(index, *args, &block)
      index = assert_index(index, :before)
      middleware = self.class::Middleware.new(*args, &block)
      middlewares.insert(index, middleware)
    end

    alias_method :insert_before, :insert

    def insert_after(index, *args, &block)
      index = assert_index(index, :after)
      insert(index + 1, *args, &block)
    end

    def swap(target, *args, &block)
      index = assert_index(target, :before)
      insert(index, *args, &block)
      middlewares.delete_at(index + 1)
    end

    def delete(target)
      middlewares.delete target
    end

    def use(*args, &block)
      middleware = self.class::Middleware.new(*args, &block)
      middlewares.push(middleware)
    end

    def build(app = nil, &block)
      app ||= block
      raise "MiddlewareStack#build requires an app" unless app
      middlewares.freeze.reverse.inject(app) { |a, e| e.build(a) }
    end

  protected

    def assert_index(index, where)
      i = index.is_a?(Integer) ? index : middlewares.index(index)
      raise "No such middleware to insert #{where}: #{index.inspect}" unless i
      i
    end
  end
end