Introduce `Headers#add`. Move `Response#add_header` upstream.

* Introduce `ActionDispatch::Http::Headers#add` to add a value to
  a multivalued header.
* Move `Response#add_header` upstream: https://github.com/rack/rack/pull/957
* Match upstream `Response#have_header?` -> `#has_header?` name change.

3 files changed, 8 insertions, 23 deletions

diff --git a/actionpack/lib/action_dispatch/http/cache.rb b/actionpack/lib/action_dispatch/http/cache.rb
index 1d0a6b6eb3..6b25ee9a70 100644
--- a/actionpack/lib/action_dispatch/http/cache.rb
+++ b/actionpack/lib/action_dispatch/http/cache.rb
@@ -59,7 +59,7 @@ module ActionDispatch
         end
 
         def last_modified?
-          have_header? LAST_MODIFIED
+          has_header? LAST_MODIFIED
         end
 
         def last_modified=(utc_time)
@@ -73,7 +73,7 @@ module ActionDispatch
         end
 
         def date?
-          have_header? DATE
+          has_header? DATE
         end
 
         def date=(utc_time)
diff --git a/actionpack/lib/action_dispatch/http/headers.rb b/actionpack/lib/action_dispatch/http/headers.rb
index 9a3aaca3f0..12f81dc1a5 100644
--- a/actionpack/lib/action_dispatch/http/headers.rb
+++ b/actionpack/lib/action_dispatch/http/headers.rb
@@ -49,6 +49,11 @@ module ActionDispatch
         @req.set_header env_name(key), value
       end
 
+      # Add a value to a multivalued header like Vary or Accept-Encoding.
+      def add(key, value)
+        @req.add_header env_name(key), value
+      end
+
       def key?(key)
         @req.has_header? env_name(key)
       end
diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
index f6f63f1f32..a27ff67114 100644
--- a/actionpack/lib/action_dispatch/http/response.rb
+++ b/actionpack/lib/action_dispatch/http/response.rb
@@ -156,31 +156,11 @@ module ActionDispatch # :nodoc:
       yield self if block_given?
     end
 
-    def have_header?(key);  headers.key? key;   end
+    def has_header?(key);   headers.key? key;   end
     def get_header(key);    headers[key];       end
     def set_header(key, v); headers[key] = v;   end
     def delete_header(key); headers.delete key; end
 
-    # Add a header that may have multiple values.
-    #
-    # Example:
-    #   response.add_header 'Vary', 'Accept'
-    #   response.add_header 'Vary', 'Accept-Encoding'
-    #   response.add_header 'Vary', 'Cookie'
-    #
-    #   assert_equal 'Accept,Accept-Encoding,Cookie', response.get_header 'Vary'
-    #
-    # http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2
-    def add_header(key, v)
-      if v.nil?
-        get_header key
-      elsif have_header? key
-        set_header key, "#{get_header key},#{v}"
-      else
-        set_header key, v
-      end
-    end
-
     def await_commit
       synchronize do
         @cv.wait_until { @committed }