aboutsummaryrefslogtreecommitdiffstats
path: root/actionpack/lib/action_controller/polymorphic_routes.rb
blob: 7c30bf077849317da72e557b852546d04253176a (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
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
module ActionController
  # Polymorphic URL helpers are methods for smart resolution to a named route call when
  # given an Active Record model instance. They are to be used in combination with
  # ActionController::Resources.
  #
  # These methods are useful when you want to generate correct URL or path to a RESTful
  # resource without having to know the exact type of the record in question.
  #
  # Nested resources and/or namespaces are also supported, as illustrated in the example:
  #
  #   polymorphic_url([:admin, @article, @comment])
  #
  # results in:
  #   
  #   admin_article_comment_url(@article, @comment)
  #
  # == Usage within the framework
  #
  # Polymorphic URL helpers are used in a number of places throughout the Rails framework:
  #
  # * <tt>url_for</tt>, so you can use it with a record as the argument, e.g.
  #   <tt>url_for(@article)</tt>;
  # * ActionView::Helpers::FormHelper uses <tt>polymorphic_path</tt>, so you can write
  #   <tt>form_for(@article)</tt> without having to specify <tt>:url</tt> parameter for the form
  #   action;
  # * <tt>redirect_to</tt> (which, in fact, uses <tt>url_for</tt>) so you can write
  #   <tt>redirect_to(post)</tt> in your controllers;
  # * ActionView::Helpers::AtomFeedHelper, so you don't have to explicitly specify URLs
  #   for feed entries.
  #
  # == Prefixed polymorphic helpers
  #
  # In addition to <tt>polymorphic_url</tt> and <tt>polymorphic_path</tt> methods, a
  # number of prefixed helpers are available as a shorthand to <tt>:action => "..."</tt>
  # in options. Those are:
  #
  # * <tt>edit_polymorphic_url</tt>, <tt>edit_polymorphic_path</tt>
  # * <tt>new_polymorphic_url</tt>, <tt>new_polymorphic_path</tt>
  # * <tt>formatted_polymorphic_url</tt>, <tt>formatted_polymorphic_path</tt>
  #
  # Example usage:
  #
  #   edit_polymorphic_path(@post)              # => "/posts/1/edit"
  #   formatted_polymorphic_path([@post, :pdf]) # => "/posts/1.pdf"
  module PolymorphicRoutes
    # Constructs a call to a named RESTful route for the given record and returns the
    # resulting URL string. For example:
    #
    #   # calls post_url(post)
    #   polymorphic_url(post) # => "http://example.com/posts/1"
    #   polymorphic_url([blog, post]) # => "http://example.com/blogs/1/posts/1"
    #   polymorphic_url([:admin, blog, post]) # => "http://example.com/admin/blogs/1/posts/1"
    #   polymorphic_url([user, :blog, post]) # => "http://example.com/users/1/blog/posts/1"
    #
    # ==== Options
    #
    # * <tt>:action</tt> - Specifies the action prefix for the named route:
    #   <tt>:new</tt>, <tt>:edit</tt>, or <tt>:formatted</tt>. Default is no prefix.
    # * <tt>:routing_type</tt> - Allowed values are <tt>:path</tt> or <tt>:url</tt>.
    #   Default is <tt>:url</tt>.
    #
    # ==== Examples
    #
    #   # an Article record
    #   polymorphic_url(record)  # same as article_url(record)
    #
    #   # a Comment record
    #   polymorphic_url(record)  # same as comment_url(record)
    #
    #   # it recognizes new records and maps to the collection
    #   record = Comment.new
    #   polymorphic_url(record)  # same as comments_url()
    #
    def polymorphic_url(record_or_hash_or_array, options = {})
      if record_or_hash_or_array.kind_of?(Array)
        record_or_hash_or_array = record_or_hash_or_array.dup
      end

      record    = extract_record(record_or_hash_or_array)
      format    = extract_format(record_or_hash_or_array, options)
      namespace = extract_namespace(record_or_hash_or_array)
      
      args = case record_or_hash_or_array
        when Hash;  [ record_or_hash_or_array ]
        when Array; record_or_hash_or_array.dup
        else        [ record_or_hash_or_array ]
      end

      inflection =
        case
        when options[:action].to_s == "new"
          args.pop
          :singular
        when record.respond_to?(:new_record?) && record.new_record?
          args.pop
          :plural
        else
          :singular
        end

      args.delete_if {|arg| arg.is_a?(Symbol) || arg.is_a?(String)}
      args << format if format
      
      named_route = build_named_route_call(record_or_hash_or_array, namespace, inflection, options)
      send!(named_route, *args)
    end

    # Returns the path component of a URL for the given record. It uses
    # <tt>polymorphic_url</tt> with <tt>:routing_type => :path</tt>.
    def polymorphic_path(record_or_hash_or_array, options = {})
      options[:routing_type] = :path
      polymorphic_url(record_or_hash_or_array, options)
    end

    %w(edit new formatted).each do |action|
      module_eval <<-EOT, __FILE__, __LINE__
        def #{action}_polymorphic_url(record_or_hash)
          polymorphic_url(record_or_hash, :action => "#{action}")
        end

        def #{action}_polymorphic_path(record_or_hash)
          polymorphic_url(record_or_hash, :action => "#{action}", :routing_type => :path)
        end
      EOT
    end

    private
      def action_prefix(options)
        options[:action] ? "#{options[:action]}_" : ""
      end

      def routing_type(options)
        options[:routing_type] || :url
      end

      def build_named_route_call(records, namespace, inflection, options = {})
        unless records.is_a?(Array)
          record = extract_record(records)
          route  = ''
        else
          record = records.pop
          route = records.inject("") do |string, parent|
            if parent.is_a?(Symbol) || parent.is_a?(String)
              string << "#{parent}_"
            else
              string << "#{RecordIdentifier.send!("singular_class_name", parent)}_"
            end
          end
        end

        if record.is_a?(Symbol) || record.is_a?(String)
          route << "#{record}_"
        else
          route << "#{RecordIdentifier.send!("#{inflection}_class_name", record)}_"
        end

        action_prefix(options) + namespace + route + routing_type(options).to_s
      end

      def extract_record(record_or_hash_or_array)
        case record_or_hash_or_array
          when Array; record_or_hash_or_array.last
          when Hash;  record_or_hash_or_array[:id]
          else        record_or_hash_or_array
        end
      end
      
      def extract_format(record_or_hash_or_array, options)
        if options[:action].to_s == "formatted" && record_or_hash_or_array.is_a?(Array)
          record_or_hash_or_array.pop
        elsif options[:format]
          options[:format]
        else
          nil
        end
      end
      
      # Remove the first symbols from the array and return the url prefix
      # implied by those symbols.
      def extract_namespace(record_or_hash_or_array)
        return "" unless record_or_hash_or_array.is_a?(Array)

        namespace_keys = []
        while (key = record_or_hash_or_array.first) && key.is_a?(String) || key.is_a?(Symbol)
          namespace_keys << record_or_hash_or_array.shift
        end

        namespace_keys.map {|k| "#{k}_"}.join
      end
  end
end