diff --git a/library/network/protocol/http/src/http_header.e b/library/network/protocol/http/src/http_header.e
index 91c8a201..a9cee805 100644
--- a/library/network/protocol/http/src/http_header.e
+++ b/library/network/protocol/http/src/http_header.e
@@ -69,23 +69,9 @@ feature {NONE} -- Initialization
 
 	make_from_raw_header_data (h: READABLE_STRING_8)
 			-- Create Current from raw header data
-        local
-        	line : detachable STRING
-			lines: LIST [READABLE_STRING_8]
         do
-            lines := h.split ('%N')
-            make_with_count (lines.count)
-            across
-            	lines as c
-            loop
-            	line := c.item
-            	if not line.is_empty then
-            		if line [line.count] = '%R' then
-						line.remove_tail (1)
-            		end
-					add_header (line)
-            	end
-			end
+			make
+			append_raw_header_data (h)
 		end
 
 feature -- Recycle
@@ -171,7 +157,28 @@ feature -- Access
 			Result := headers.new_cursor
 		end
 
-feature -- Header: filling
+feature -- Header: adding
+
+	append_raw_header_data (h: READABLE_STRING_8)
+			-- Append raw header data `h' to Current
+        local
+        	line : detachable STRING
+			lines: LIST [READABLE_STRING_8]
+        do
+            lines := h.split ('%N')
+			headers.grow (headers.count + lines.count)
+            across
+            	lines as c
+            loop
+            	line := c.item
+            	if not line.is_empty then
+            		if line [line.count] = '%R' then
+						line.remove_tail (1)
+            		end
+					add_header (line)
+            	end
+			end
+		end
 
 	append_array (a_headers: ARRAY [TUPLE [key: READABLE_STRING_8; value: READABLE_STRING_8]])
 			-- Append array of key,value headers
@@ -180,7 +187,7 @@ feature -- Header: filling
 			across
 				a_headers as c
 			loop
-				put_header_key_value (c.item.key, c.item.value)
+				add_header_key_value (c.item.key, c.item.value)
 			end
 		end
 
@@ -195,6 +202,54 @@ feature -- Header: filling
 			end
 		end
 
+feature -- Header: merging
+
+	put_raw_header_data (h: READABLE_STRING_8)
+			-- Append raw header data `h' to Current
+			-- Overwrite existing header with same name
+        local
+        	line : detachable STRING
+			lines: LIST [READABLE_STRING_8]
+        do
+            lines := h.split ('%N')
+			headers.grow (headers.count + lines.count)
+            across
+            	lines as c
+            loop
+            	line := c.item
+            	if not line.is_empty then
+            		if line [line.count] = '%R' then
+						line.remove_tail (1)
+            		end
+					put_header (line)
+            	end
+			end
+		end
+
+	put_array (a_headers: ARRAY [TUPLE [key: READABLE_STRING_8; value: READABLE_STRING_8]])
+			-- Append array of key,value headers
+			-- Overwrite existing header with same name
+		do
+			headers.grow (headers.count + a_headers.count)
+			across
+				a_headers as c
+			loop
+				put_header_key_value (c.item.key, c.item.value)
+			end
+		end
+
+	put_header_object (h: HTTP_HEADER)
+			-- Append headers from `h'
+			-- Overwrite existing header with same name
+		do
+			headers.grow (headers.count + h.headers.count)
+			across
+				h.headers as c
+			loop
+				put_header (c.item.string)
+			end
+		end
+
 feature -- Header change: general
 
 	add_header (h: READABLE_STRING_8)
diff --git a/library/server/ewsgi/connectors/cgi/src/wgi_cgi_connector.e b/library/server/ewsgi/connectors/cgi/src/wgi_cgi_connector.e
index dc98f64f..56718745 100644
--- a/library/server/ewsgi/connectors/cgi/src/wgi_cgi_connector.e
+++ b/library/server/ewsgi/connectors/cgi/src/wgi_cgi_connector.e
@@ -44,6 +44,7 @@ feature -- Execution
 				create req.make ((create {EXECUTION_ENVIRONMENT}).starting_environment_variables, create {WGI_CGI_INPUT_STREAM}.make, Current)
 				create res.make (create {WGI_CGI_OUTPUT_STREAM}.make, create {WGI_CGI_ERROR_STREAM}.make)
 				service.execute (req, res)
+				res.push
 			else
 				if attached (create {EXCEPTION_MANAGER}).last_exception as e and then attached e.exception_trace as l_trace then
 					if res /= Void then
@@ -53,6 +54,7 @@ feature -- Execution
 						if res.message_writable then
 							res.put_string ("<pre>" + l_trace + "</pre>")
 						end
+						res.push
 					end
 				end
 			end
diff --git a/library/server/ewsgi/connectors/libfcgi/src/wgi_libfcgi_connector.e b/library/server/ewsgi/connectors/libfcgi/src/wgi_libfcgi_connector.e
index 08efc4a4..32f54566 100644
--- a/library/server/ewsgi/connectors/libfcgi/src/wgi_libfcgi_connector.e
+++ b/library/server/ewsgi/connectors/libfcgi/src/wgi_libfcgi_connector.e
@@ -65,6 +65,7 @@ feature -- Execution
 				create req.make (vars, a_input, Current)
 				create res.make (a_output, a_output)
 				service.execute (req, res)
+				res.push
 			else
 				if attached (create {EXCEPTION_MANAGER}).last_exception as e and then attached e.exception_trace as l_trace then
 					if res /= Void then
@@ -74,6 +75,7 @@ feature -- Execution
 						if res.message_writable then
 							res.put_string ("<pre>" + l_trace + "</pre>")
 						end
+						res.push
 					end
 				end
 			end
diff --git a/library/server/ewsgi/connectors/nino/src/wgi_nino_connector.e b/library/server/ewsgi/connectors/nino/src/wgi_nino_connector.e
index e66ebbd5..45f0a401 100644
--- a/library/server/ewsgi/connectors/nino/src/wgi_nino_connector.e
+++ b/library/server/ewsgi/connectors/nino/src/wgi_nino_connector.e
@@ -133,10 +133,10 @@ feature -- Server
 			res: detachable WGI_NINO_RESPONSE_STREAM
 		do
 			create req.make (env, create {WGI_NINO_INPUT_STREAM}.make (a_socket), Current)
-			create res.make (create {WGI_NINO_OUTPUT_STREAM}.make (a_socket), Void)
+			create res.make (create {WGI_NINO_OUTPUT_STREAM}.make (a_socket), create {WGI_NINO_ERROR_STREAM}.make_stderr (a_socket.descriptor.out))
 			req.set_meta_string_variable ("RAW_HEADER_DATA", a_headers_text)
 			service.execute (req, res)
-			res.commit
+			res.push
 		end
 
 note
diff --git a/library/server/ewsgi/connectors/nino/src/wgi_nino_error_stream.e b/library/server/ewsgi/connectors/nino/src/wgi_nino_error_stream.e
new file mode 100644
index 00000000..facbfb66
--- /dev/null
+++ b/library/server/ewsgi/connectors/nino/src/wgi_nino_error_stream.e
@@ -0,0 +1,70 @@
+note
+	description: "Summary description for WGI_CGI_ERROR_STREAM."
+	legal: "See notice at end of class."
+	status: "See notice at end of class."
+	date: "$Date$"
+	revision: "$Revision$"
+
+class
+	WGI_NINO_ERROR_STREAM
+
+inherit
+	WGI_ERROR_STREAM
+
+create
+	make,
+	make_stderr,
+	make_stdout
+
+feature {NONE} -- Initialization
+
+	make (a_identifier: READABLE_STRING_8; a_file: PLAIN_TEXT_FILE)
+		do
+			identifier := a_identifier
+			output := a_file
+		end
+
+	make_stderr (a_identifier: READABLE_STRING_8)
+		do
+			make (a_identifier, io.error)
+		end
+
+	make_stdout (a_identifier: READABLE_STRING_8)
+		do
+			make (a_identifier, io.error)
+		end
+
+feature -- Access
+
+	identifier: READABLE_STRING_8
+
+	output: FILE
+
+feature -- Error
+
+	put_error (a_message: READABLE_STRING_8)
+		local
+			s: STRING
+		do
+			create s.make (a_message.count + identifier.count + 4)
+			s.append_character ('[')
+			s.append (identifier)
+			s.append_character (']')
+			s.append_character (' ')
+			s.append (a_message)
+			s.append_character ('%N')
+				-- Display it at once.
+			output.put_string (s)
+		end
+
+note
+	copyright: "2011-2011, Eiffel Software and others"
+	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
+	source: "[
+			Eiffel Software
+			5949 Hollister Ave., Goleta, CA 93117 USA
+			Telephone 805-685-1006, Fax 805-685-6869
+			Website http://www.eiffel.com
+			Customer support http://support.eiffel.com
+		]"
+end
diff --git a/library/server/ewsgi/specification/response/wgi_filter_response.e b/library/server/ewsgi/specification/response/wgi_filter_response.e
index 5a1ce391..ec7235a2 100644
--- a/library/server/ewsgi/specification/response/wgi_filter_response.e
+++ b/library/server/ewsgi/specification/response/wgi_filter_response.e
@@ -17,6 +17,7 @@ feature {NONE} -- Initialization
 	make_with_response (res: WGI_RESPONSE)
 		do
 			wgi_response := res
+			res.set_post_commit_action (agent commit)
 		end
 
 	wgi_response: WGI_RESPONSE
@@ -26,7 +27,7 @@ feature {WGI_CONNECTOR, WGI_SERVICE} -- Commit
 	commit
 			-- Commit the current response
 		do
-			-- do nothing, this will be done internal on the original `wgi_response' object
+			wgi_response.set_post_commit_action (Void)
 		end
 
 feature -- Status report
@@ -129,7 +130,7 @@ feature -- Error reporting
 		end
 
 note
-	copyright: "2011-2012, Jocelyn Fiat, Javier Velilla, Eiffel Software and others"
+	copyright: "2011-2013, Jocelyn Fiat, Javier Velilla, Eiffel Software and others"
 	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
 	source: "[
 			Eiffel Software
diff --git a/library/server/ewsgi/specification/response/wgi_response.e b/library/server/ewsgi/specification/response/wgi_response.e
index 25a570a4..11db233e 100644
--- a/library/server/ewsgi/specification/response/wgi_response.e
+++ b/library/server/ewsgi/specification/response/wgi_response.e
@@ -8,6 +8,15 @@ deferred class
 
 feature {WGI_CONNECTOR, WGI_SERVICE} -- Commit
 
+	push
+			-- Commit and push response
+		do
+			commit
+			if attached post_commit_action as act then
+				act.call (Void)
+			end
+		end
+
 	commit
 			-- Commit the current response
 		deferred
@@ -17,6 +26,21 @@ feature {WGI_CONNECTOR, WGI_SERVICE} -- Commit
 			message_committed: message_committed
 		end
 
+feature -- Access: commit
+
+	post_commit_action: detachable PROCEDURE [ANY, TUPLE]
+			-- Action associated with the final `commit' execution
+			-- Note: useful to trigger action just after the
+			--       response is transfered to the client.
+
+feature -- Change: commit
+
+	set_post_commit_action (act: like post_commit_action)
+			-- Assign `act' to `post_commit_action'
+		do
+			post_commit_action := act
+		end
+
 feature -- Status report
 
 	status_committed: BOOLEAN
@@ -131,7 +155,7 @@ feature -- Error reporting
 		end
 
 note
-	copyright: "2011-2012, Jocelyn Fiat, Javier Velilla, Eiffel Software and others"
+	copyright: "2011-2013, Jocelyn Fiat, Javier Velilla, Eiffel Software and others"
 	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
 	source: "[
 			Eiffel Software
diff --git a/library/server/wsf/src/implementation/wsf_wgi_delayed_header_response.e b/library/server/wsf/src/implementation/wsf_wgi_delayed_header_response.e
new file mode 100644
index 00000000..006b67ff
--- /dev/null
+++ b/library/server/wsf/src/implementation/wsf_wgi_delayed_header_response.e
@@ -0,0 +1,108 @@
+note
+	description: "Summary description for {WGI_DELAYED_HEADER_RESPONSE}."
+	date: "$Date$"
+	revision: "$Revision$"
+
+class
+	WSF_WGI_DELAYED_HEADER_RESPONSE
+
+inherit
+	WGI_FILTER_RESPONSE
+		redefine
+			commit,
+			put_character,
+			put_string,
+			put_substring,
+			flush,
+			message_writable
+		end
+
+	WSF_RESPONSE_EXPORTER
+
+create
+	make
+
+feature {NONE} -- Initialization
+
+	make (r: WGI_RESPONSE; res: WSF_RESPONSE)
+		do
+			wsf_response := res
+			make_with_response (r)
+		end
+
+feature {NONE} -- Implementation		
+
+	wsf_response: WSF_RESPONSE
+
+	commit
+		do
+			Precursor
+			if not header_committed then
+				process_header
+			end
+		end
+
+	process_header
+		require
+			header_not_committed: not header_committed
+		do
+				-- If no content is sent, the final `{WGI_REPONSE}.push' will call `process_header'
+				-- via `{WGI_RESPONSE}.post_commit_action'
+			wgi_response.set_post_commit_action (Void)
+
+				-- commit status code and reason phrase
+				-- commit header text
+			wsf_response.process_header
+
+				-- update wgi_response on wsf_response to send content directly
+			wsf_response.set_wgi_response (wgi_response)
+		ensure
+			header_committed: header_committed
+		end
+
+feature -- Status report	
+
+	message_writable: BOOLEAN = True
+			-- Can message be written?
+
+feature -- Output operation
+
+	put_character (c: CHARACTER_8)
+			-- Send the character `c'
+		do
+			process_header
+			Precursor (c)
+		end
+
+	put_string (s: READABLE_STRING_8)
+			-- Send the string `s'
+		do
+			process_header
+			Precursor (s)
+		end
+
+	put_substring (s: READABLE_STRING_8; a_begin_index, a_end_index: INTEGER)
+			-- Send the substring `s[a_begin_index:a_end_index]'
+		do
+			process_header
+			Precursor (s, a_begin_index, a_end_index)
+		end
+
+	flush
+			-- Flush if it makes sense
+		do
+			process_header
+			Precursor
+		end
+
+note
+	copyright: "2011-2013, Jocelyn Fiat, Javier Velilla, Olivier Ligot, Eiffel Software and others"
+	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
+	source: "[
+			Eiffel Software
+			5949 Hollister Ave., Goleta, CA 93117 USA
+			Telephone 805-685-1006, Fax 805-685-6869
+			Website http://www.eiffel.com
+			Customer support http://support.eiffel.com
+		]"
+end
diff --git a/library/server/wsf/src/wsf_response.e b/library/server/wsf/src/wsf_response.e
index edd69fed..c70c1da3 100644
--- a/library/server/wsf/src/wsf_response.e
+++ b/library/server/wsf/src/wsf_response.e
@@ -28,15 +28,32 @@ convert
 feature {NONE} -- Initialization
 
 	make_from_wgi (r: WGI_RESPONSE)
+		local
+			wres: detachable WSF_WGI_DELAYED_HEADER_RESPONSE
 		do
 			transfered_content_length := 0
+			create header.make
 			wgi_response := r
+			create wres.make (r, Current)
+			wgi_response := wres
+			set_status_code ({HTTP_STATUS_CODE}.ok) -- Default value
 		end
 
 feature {WSF_RESPONSE_EXPORTER} -- Properties		
 
 	wgi_response: WGI_RESPONSE
-			-- Associated WGI_RESPONSE
+			-- Associated WGI_RESPONSE.
+
+	header: WSF_HEADER
+			-- Associated response header.	
+
+feature {WSF_RESPONSE_EXPORTER} -- Change		
+
+	set_wgi_response (res: WGI_RESPONSE)
+			-- Set associated WGI_RESPONSE
+		do
+			wgi_response := res
+		end
 
 feature -- Status report
 
@@ -76,6 +93,7 @@ feature -- Status setting
 			-- Set response status code
 			-- Should be done before sending any data back to the client
 			--| note: the status is really sent when the header are set
+			--| Default value might be set to 200 {HTTP_HEADER}.ok.
 		require
 			a_code_valid: a_code > 0
 			status_not_set: not status_committed
@@ -112,61 +130,146 @@ feature -- Status setting
 	status_reason_phrase: detachable READABLE_STRING_8
 			-- Custom status reason phrase (optional)
 
+feature {WSF_RESPONSE_EXPORTER} -- Header output operation
+
+	process_header
+		require
+			header_not_committed: not header_committed
+		do
+			if not header_committed then
+					-- commit status code and reason phrase
+				wgi_response.set_status_code (status_code, status_reason_phrase)
+					-- commit header text
+				wgi_response.put_header_text (header.string)
+			end
+		ensure
+			status_committed: status_committed
+			header_committed: header_committed
+		end
+
+	report_content_already_sent_and_header_ignored
+		do
+			put_error ("Content already sent, new header text ignored!")
+		end
+
 feature -- Header output operation
 
-	put_header_text (a_text: READABLE_STRING_8)
-			-- Sent `a_text' and just before send the status code
+	put_header_line (h: READABLE_STRING_8)
+			-- Put header `h'
+			-- Replace any existing value
+		require
+			header_not_committed: not header_committed
+		do
+			if header_committed then
+				report_content_already_sent_and_header_ignored
+			else
+				header.put_header (h)
+			end
+		end
+
+	add_header_line (h: READABLE_STRING_8)
+			-- Add header `h'
+			-- This can lead to duplicated header entries
+		require
+			header_not_committed: not header_committed
+		do
+			if header_committed then
+				report_content_already_sent_and_header_ignored
+			else
+				header.add_header (h)
+			end
+		end
+
+	put_header_text (a_text: READABLE_STRING_8)
+			-- Put the multiline header `a_text'
+			-- Overwite potential existing header
 		require
-			status_set: status_is_set
 			header_not_committed: not header_committed
 			a_text_ends_with_single_crlf: a_text.count > 2 implies not a_text.substring (a_text.count - 2, a_text.count).same_string ("%R%N")
 			a_text_does_not_end_with_double_crlf: a_text.count > 4 implies not a_text.substring (a_text.count - 4, a_text.count).same_string ("%R%N%R%N")
 		do
-			wgi_response.set_status_code (status_code, status_reason_phrase)
-			wgi_response.put_header_text (a_text)
+			if header_committed then
+				report_content_already_sent_and_header_ignored
+			else
+				header.append_raw_header_data (a_text)
+			end
 		ensure
-			status_set: status_is_set
-			status_committed: status_committed
-			header_committed: header_committed
 			message_writable: message_writable
 		end
 
+	add_header_text (a_text: READABLE_STRING_8)
+			-- Add the multiline header `a_text'
+			-- Does not replace existing header with same name
+			-- This could leads to multiple header with the same name
+		require
+			header_not_committed: not header_committed
+			a_text_ends_with_single_crlf: a_text.count > 2 implies not a_text.substring (a_text.count - 2, a_text.count).same_string ("%R%N")
+			a_text_does_not_end_with_double_crlf: a_text.count > 4 implies not a_text.substring (a_text.count - 4, a_text.count).same_string ("%R%N%R%N")
+		do
+			if header_committed then
+				report_content_already_sent_and_header_ignored
+			else
+				header.append_raw_header_data (a_text)
+			end
+		ensure
+			status_set: status_is_set
+			message_writable: message_writable
+		end
+
+feature -- Header output operation: helpers
+
 	put_header (a_status_code: INTEGER; a_headers: detachable ARRAY [TUPLE [name: READABLE_STRING_8; value: READABLE_STRING_8]])
-			-- Send headers with status `a_status', and headers from `a_headers'
+			-- Put headers with status `a_status', and headers from `a_headers'
 		require
 			status_not_committed: not status_committed
 			header_not_committed: not header_committed
 		local
 			h: HTTP_HEADER
 		do
-			set_status_code (a_status_code)
 			if a_headers /= Void then
 				create h.make_from_array (a_headers)
 				put_header_text (h.string)
 			end
 		ensure
 			status_set: status_is_set
-			header_committed: header_committed
+			message_writable: message_writable
+		end
+
+	add_header (a_status_code: INTEGER; a_headers: detachable ARRAY [TUPLE [name: READABLE_STRING_8; value: READABLE_STRING_8]])
+			-- Put headers with status `a_status', and headers from `a_headers'
+		require
+			status_not_committed: not status_committed
+			header_not_committed: not header_committed
+		local
+			h: HTTP_HEADER
+		do
+			if a_headers /= Void then
+				create h.make_from_array (a_headers)
+				add_header_text (h.string)
+			end
+		ensure
+			status_set: status_is_set
 			message_writable: message_writable
 		end
 
 	put_header_lines (a_lines: ITERABLE [TUPLE [name: READABLE_STRING_8; value: READABLE_STRING_8]])
-			-- Send headers from `a_lines'
-		local
-			h: STRING_8
+			-- Put headers from `a_lines'
+		require
+			header_not_committed: not header_committed
 		do
-			create h.make (256)
-			across
-				a_lines as c
-			loop
-				h.append (c.item.name)
-				h.append_character (':')
-				h.append_character (' ')
-				h.append (c.item.value)
-				h.append_character ('%R')
-				h.append_character ('%N')
+			across a_lines as c loop
+				put_header_line (c.item.name + ": " + c.item.value)
+			end
+		end
+
+	add_header_lines (a_lines: ITERABLE [TUPLE [name: READABLE_STRING_8; value: READABLE_STRING_8]])
+			-- Add headers from `a_lines'
+		require
+			header_not_committed: not header_committed
+		do
+			across a_lines as c loop
+				add_header_line (c.item.name + ": " + c.item.value)
 			end
-			put_header_text (h)
 		end
 
 feature -- Output report
@@ -376,7 +479,7 @@ feature -- Error reporting
 		end
 
 note
-	copyright: "2011-2012, Jocelyn Fiat, Javier Velilla, Olivier Ligot, Eiffel Software and others"
+	copyright: "2011-2013, Jocelyn Fiat, Javier Velilla, Olivier Ligot, Eiffel Software and others"
 	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
 	source: "[
 			Eiffel Software