setup spec for new headers

Author: David Roy

.rspec

@@ -0,0 +1,2 @@
+--color
+--format documentation

README.md

@@ -18,6 +18,12 @@ require 'grape/cache_control'
 # Cache-Control:public,max-age=900
 cache_control :public, max_age: 900
 
+# Cache-Control:public,max-age=900,stale-while-revalidate=1600
+cache_control :public, max_age: 900, stale_while_revalidate: 1600
+
+# Cache-Control:public,max-age=900,stale-while-error=1600
+cache_control :public, max_age: 900, stale_while_error: 1600
+
 # Cache-Control:public,no-store,max-age=900,s-maxage=86400
 cache_control :public, :no_store, max_age: 900, s_maxage:86400
 

lib/grape/cache_control.rb

@@ -10,7 +10,9 @@ module CacheControl
     EXPIRES               = 'Expires'.freeze
     TRUE                  = 'true'.freeze
     SETTABLE_DIRECTIVES   = [:max_age, :s_maxage].freeze
-    TRUTHY_DIRECTIVES     = [:public, :private, :no_cache, :no_store, :no_transform, :must_revalidate, :proxy_revalidate].freeze
+    TRUTHY_DIRECTIVES     = [:public, :private, :no_cache, :no_store, :no_transform,
+                             :must_revalidate, :proxy_revalidate, :stale_while_revalidate,
+                             :stale_while_error].freeze
     ALL_DIRECTIVES        = (TRUTHY_DIRECTIVES | SETTABLE_DIRECTIVES).freeze
 
     ALL_DIRECTIVES.each do |d|

spec/unit/grape/cache_control_spec.rb

@@ -66,6 +66,23 @@ def app
         expect(last_response.headers['Cache-Control'].split(', ')).to include('public', 'max-age=60')
       end
 
+      it 'supports stale-while-revalidate' do
+        subject.get('/stale_blueberries') do
+          cache_control :public, stale_while_revalidate: 120
+        end
+
+        get 'stale_blueberries'
+        expect(last_response.headers['Cache-Control'].split(', ')).to include('public', 'stale-while-revalidate=120')
+      end
+
+      it 'supports stale-while-error' do
+        subject.get('/error_blueberries') do
+          cache_control :public, stale_while_error: 120
+        end
+
+        get 'error_blueberries'
+        expect(last_response.headers['Cache-Control'].split(', ')).to include('public', 'stale-while-error=120')
+      end
     end
 
     describe 'expires' do