Fixed the case-insensitive nature of ignored response headers

Author: rmm5t

lib/rack/cache/context.rb

@@ -272,7 +272,8 @@ def store(response)
 
     # Remove all ignored response headers before writing to the cache.
     def strip_ignore_headers(response)
-      record :ignore if response.headers.reject! { |name, value| ignore_headers.include? name }
+      stripped_values = ignore_headers.map { |name| response.headers.delete(name) }
+      record :ignore if stripped_values.any?
     end
 
     def log_error(exception)

test/context_test.rb

@@ -97,6 +97,18 @@
     response.headers['Set-Cookie'].should.be.nil
   end
 
+  it 'does remove all configured ignore_headers from a cacheable response' do
+    respond_with 200, 'Cache-Control' => 'public', 'ETag' => '"FOO"', 'SET-COOKIE' => 'TestCookie=OK', 'X-Strip-Me' => 'Secret'
+    get '/', 'rack-cache.ignore_headers' => ['set-cookie', 'x-strip-me']
+
+    app.should.be.called
+    response.should.be.ok
+    cache.trace.should.include :store
+    cache.trace.should.include :ignore
+    response.headers['Set-Cookie'].should.be.nil
+    response.headers['x-strip-me'].should.be.nil
+  end
+
   it 'does not remove Set-Cookie response header from a private response' do
     respond_with 200, 'Cache-Control' => 'private', 'Set-Cookie' => 'TestCookie=OK'
     get '/'