Merge branch 'master' of git://github.com/rails/rails

1 files changed, 60 insertions, 0 deletions

diff --git a/activemodel/lib/active_model/serializer.rb b/activemodel/lib/active_model/serializer.rb
new file mode 100644
index 0000000000..5b603bdbd7
--- /dev/null
+++ b/activemodel/lib/active_model/serializer.rb
@@ -0,0 +1,60 @@
+require 'active_support/core_ext/hash/except'
+require 'active_support/core_ext/hash/slice'
+
+module ActiveModel
+  class Serializer
+    attr_reader :options
+
+    def initialize(serializable, options = nil)
+      @serializable = serializable
+      @options = options ? options.dup : {}
+
+      @options[:only] = Array.wrap(@options[:only]).map { |n| n.to_s }
+      @options[:except] = Array.wrap(@options[:except]).map { |n| n.to_s }
+    end
+
+    def serialize
+      raise NotImplemented
+    end
+
+    def to_s(&block)
+      serialize(&block)
+    end
+
+    # To replicate the behavior in ActiveRecord#attributes,
+    # <tt>:except</tt> takes precedence over <tt>:only</tt>.  If <tt>:only</tt> is not set
+    # for a N level model but is set for the N+1 level models,
+    # then because <tt>:except</tt> is set to a default value, the second
+    # level model can have both <tt>:except</tt> and <tt>:only</tt> set.  So if
+    # <tt>:only</tt> is set, always delete <tt>:except</tt>.
+    def serializable_attribute_names
+      attribute_names = @serializable.attributes.keys.sort
+
+      if options[:only].any?
+        attribute_names &= options[:only]
+      elsif options[:except].any?
+        attribute_names -= options[:except]
+      end
+
+      attribute_names
+    end
+
+    def serializable_method_names
+      Array.wrap(options[:methods]).inject([]) do |methods, name|
+        methods << name if @serializable.respond_to?(name.to_s)
+        methods
+      end
+    end
+
+    def serializable_names
+      serializable_attribute_names + serializable_method_names
+    end
+
+    def serializable_hash
+      serializable_names.inject({}) { |hash, name|
+        hash[name] = @serializable.send(name)
+        hash
+      }
+    end
+  end
+end