From 83a69012c70678c0f10af1d92cc7a71e5eaeec37 Mon Sep 17 00:00:00 2001
From: Gavin Joyce <gavinjoyce@gmail.com>
Date: Tue, 31 May 2016 14:34:36 +0100
Subject: [PATCH] add support for @context[:attribute_whitelist] and
 @context[:attribute_blacklist]

---
 lib/restpack_serializer/serializable.rb | 36 +++++++++++++++++++++++
 spec/serializable/serializer_spec.rb    | 38 +++++++++++++++++++++++++
 2 files changed, 74 insertions(+)

diff --git a/lib/restpack_serializer/serializable.rb b/lib/restpack_serializer/serializable.rb
index 3f66f02..5822e53 100644
--- a/lib/restpack_serializer/serializable.rb
+++ b/lib/restpack_serializer/serializable.rb
@@ -37,6 +37,7 @@ def as_json(model, context = {})
         return model.map { |item| as_json(item, context) }
       end
 
+      apply_whitelist_and_blacklist(context)
       @model, @context = model, context
 
       data = {}
@@ -72,6 +73,41 @@ def add_custom_attributes(data)
       data.merge!(custom) if custom
     end
 
+    def apply_whitelist_and_blacklist(context)
+      blacklist = context[:attribute_blacklist]
+      whitelist = context[:attribute_whitelist]
+
+      if blacklist.present? && whitelist.present?
+        raise ArgumentError.new "the context can't define both an `attribute_whitelist` and an `attribute_blacklist`"
+      end
+
+      if blacklist.present?
+        blacklist = csv_to_symbol_array(blacklist)
+        self.class.serializable_attributes.each do |key, value|
+          if blacklist.include? key
+            context[value[:include_method_name]] = false
+          end
+        end
+      end
+
+      if whitelist.present?
+        whitelist = csv_to_symbol_array(whitelist)
+        self.class.serializable_attributes.each do |key, value|
+          unless whitelist.include? key
+            context[value[:include_method_name]] = false
+          end
+        end
+      end
+    end
+
+    def csv_to_symbol_array(maybe_csv)
+      if maybe_csv.is_a? String
+        maybe_csv.split(',').map {|a| a.strip.to_sym}
+      else
+        maybe_csv
+      end
+    end
+
     def add_links(model, data)
       self.class.associations.each do |association|
         data[:links] ||= {}
diff --git a/spec/serializable/serializer_spec.rb b/spec/serializable/serializer_spec.rb
index f667b26..747d2ab 100644
--- a/spec/serializable/serializer_spec.rb
+++ b/spec/serializable/serializer_spec.rb
@@ -198,6 +198,44 @@ def custom_attributes
           ]
         }
       end
+
+      it "excludes a blacklist of attributes if specified as an array" do
+        serializer.as_json(person, { attribute_blacklist: [:name, :description] }).should == {
+          id: '123',
+          href: '/people/123',
+          custom_key: 'custom value for model id 123'
+        }
+      end
+
+      it "excludes a blacklist of attributes if specified as a string" do
+        serializer.as_json(person, { attribute_blacklist: 'name, description' }).should == {
+          id: '123',
+          href: '/people/123',
+          custom_key: 'custom value for model id 123'
+        }
+      end
+
+      it "includes a whitelist of attributes if specified as an array" do
+        serializer.as_json(person, { attribute_whitelist: [:name, :description] }).should == {
+          name: 'Gavin',
+          description: 'This is person #123',
+          custom_key: 'custom value for model id 123'
+        }
+      end
+
+      it "includes a whitelist of attributes if specified as a string" do
+        serializer.as_json(person, { attribute_whitelist: 'name, description' }).should == {
+          name: 'Gavin',
+          description: 'This is person #123',
+          custom_key: 'custom value for model id 123'
+        }
+      end
+
+      it "raises an exception if both the whitelist and blacklist are provided" do
+        expect do
+          serializer.as_json(person, { attribute_whitelist: [:name], attribute_blacklist: [:id] })
+        end.to raise_error(ArgumentError, "the context can't define both an `attribute_whitelist` and an `attribute_blacklist`")
+      end
     end
 
     context "links" do