Allow multiple blanks for handles

.travis.yml

@@ -1,6 +1,14 @@
 language: ruby
 sudo: false
+script: bundle exec rspec
 rvm:
   - "2.0.0"
-  - "2.2.1"
-script: bundle exec rspec
+  - "2.2.2"
+  - "2.3.1"
+gemfile:
+  - Gemfile
+  - gemfiles/rails-4.2.gemfile
+matrix:
+  exclude:
+    - rvm: "2.0.0"
+      gemfile: Gemfile

gemfiles/rails-4.2.gemfile

@@ -0,0 +1,6 @@
+source "http://rubygems.org"
+
+gemspec path: '..'
+
+gem 'rails', '~> 4.2'
+gem 'rack', '< 2.0'

lib/concern.rb

@@ -13,13 +13,13 @@ def acts_as_permalink(options={})
           attr_readonly self.acts_as_permalink_config.to
         end
 
+        allow_blank = self.acts_as_permalink_config.allow_blank
         if self.acts_as_permalink_config.scope
-          validates self.acts_as_permalink_config.to, uniqueness: {scope: self.acts_as_permalink_config.scope}
+          validates self.acts_as_permalink_config.to, uniqueness: {scope: self.acts_as_permalink_config.scope, allow_blank: allow_blank}
         else
-          validates self.acts_as_permalink_config.to, uniqueness: true
+          validates self.acts_as_permalink_config.to, uniqueness: {allow_blank: allow_blank}
         end
 
-
         include Acts::Permalink::InstanceMethods
       end
     end
@@ -38,6 +38,7 @@ def build_permalink
         config = self.class.base_class.acts_as_permalink_config
 
         text = self.public_send(config.from)
+        return nil if text.blank? && config.allow_blank
         text = [self.class.base_class.to_s, rand(10000)].join(config.separator) if text.blank?
         text = Acts::Permalink::Conversion.convert(text, separator: config.separator, max_length: config.max_length)
 

lib/config.rb

@@ -1,7 +1,7 @@
 module Acts
   module Permalink
     class Config
-      attr_reader :to, :from, :separator, :max_length, :scope, :allow_update
+      attr_reader :to, :from, :separator, :max_length, :scope, :allow_update, :allow_blank
 
       def initialize(options={})
         @config = options.with_indifferent_access
@@ -14,6 +14,7 @@ def initialize(options={})
         @max_length = @config[:max_length].to_i rescue 0
         @max_length = 60 unless @max_length > 0
         @allow_update = !!@config[:allow_update]
+        @allow_blank = !!@config[:allow_blank]
       end
     end
   end

spec/lib/acts_as_permalink_spec.rb

@@ -83,6 +83,23 @@ class LongThing < ActiveRecord::Base
 
   end
 
+  describe "column that allows blank" do
+    class BlankThing < ActiveRecord::Base
+      acts_as_permalink max_length: 100, allow_blank: true
+    end
+
+    it "allows multiple blank titles" do
+      expect(BlankThing.create!(title: "").permalink).to be_nil
+      expect(BlankThing.create!(title: "").permalink).to be_nil
+    end
+
+    it "provides permalink" do
+      expect(BlankThing.create!(title: "").permalink).to be_nil
+      expect(BlankThing.create!(title: "My New Thing").permalink).to eq("my-new-think")
+    end
+
+  end
+
   describe "single table inheritance" do
     class Thing < ActiveRecord::Base
       acts_as_permalink

spec/lib/config_spec.rb

@@ -10,6 +10,7 @@
     expect(config.max_length).to eq(60)
     expect(config.scope).to be_nil
     expect(config.allow_update).to be_falsy
+    expect(config.allow_blank).to be_falsy
   end
 
   it "allows the underscore property" do