Support persistent connection, even in single thread mode (i.e concurrency=none).

Warning: as there is no concurrent request handling in single threaded mode,
            it is recommended to either set the keep_alive_timeout to a small value,
            or disable persistent connection by setting max_keep_alive_requests to 0.
Change the default keep_alive_timeout from 15 to 5 seconds.
Accept -1 as value of max_keep_alive_requests to have unlimited number of request in the same persistent connection.

library/server/httpd/concurrency/none/httpd_request_handler.e

@@ -8,19 +8,9 @@ deferred class
 
 inherit
 	HTTPD_REQUEST_HANDLER_I
-		redefine
-			is_persistent_connection_supported
-		end
-
-feature -- Status report	
-
-	is_persistent_connection_supported: BOOLEAN = False
-			-- <Precursor>
-			-- When there is no concurrency support, do not try to support
-			-- persistent connection!	
 
 note
-	copyright: "2011-2015, Jocelyn Fiat, Javier Velilla, Eiffel Software and others"
+	copyright: "2011-2017, Jocelyn Fiat, Javier Velilla, Eiffel Software and others"
 	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
 	source: "[
 			Eiffel Software

library/server/httpd/configuration/httpd_constants.e

@@ -25,7 +25,7 @@ feature -- Default timeout settings
 
 feature -- Default persistent connection settings
 
-	default_keep_alive_timeout: INTEGER = 15 -- seconds
+	default_keep_alive_timeout: INTEGER = 5 -- seconds
 	default_max_keep_alive_requests: INTEGER = 100
 
 note

library/server/httpd/httpd_request_handler_i.e

@@ -140,7 +140,8 @@ feature -- Settings
 	is_persistent_connection_supported: BOOLEAN
 			-- Is persistent connection supported?
 		do
-			Result := {HTTPD_SERVER}.is_persistent_connection_supported and then max_keep_alive_requests > 0
+			Result := {HTTPD_SERVER}.is_persistent_connection_supported and then 
+					max_keep_alive_requests /= 0 --| `-1` no limit			
 		end
 
 	is_next_persistent_connection_supported: BOOLEAN
@@ -247,7 +248,8 @@ feature -- Execution
 				l_exit
 			loop
 				n := n + 1
-				if n >= m then
+					-- If `m` is `-1`, no limit for the number of keep_alive requests.
+				if m >= 0 and n >= m then
 					is_next_persistent_connection_supported := False
 				elseif n > 1 and is_verbose then
 					log ("Reuse connection (" + n.out + ")", information_level)

library/server/wsf/connector/standalone/wsf_standalone_service_options.e

@@ -104,11 +104,26 @@ feature -- Access: persistent connection
 			-- Maximum number of requests allowed per persistent connection.
 			-- Recommended a high setting.
 			-- To disable KeepAlive, set `max_keep_alive_requests' to 0.
+			-- To have no limit, set `max_keep_alive_requests' to -1.
 			-- By default: {HTTPD_CONFIGURATION_I}.default_max_keep_alive_requests .	
 		do
 			Result := option_integer_value ("max_keep_alive_requests", 0)
 		end
 
+	persistent_connection_disabled: BOOLEAN
+			-- Persistent connection disabled?
+			-- (or Keep-Alive disabled).
+		do
+			Result := max_keep_alive_requests = 0
+		end
+
+	has_unlimited_keep_alive_requests: BOOLEAN
+			-- Has unlimited count of keep alive requests.
+			-- i.e no limit of number of requests allowed per persistent connection.
+		do
+			Result := max_keep_alive_requests < 0
+		end
+
 feature -- Access: SSL	
 
 	is_secure: BOOLEAN assign set_is_secure
@@ -205,6 +220,16 @@ feature -- Element change
 			set_numeric_option ("max_keep_alive_requests", nb)
 		end
 
+	set_unlimited_keep_alive_requests
+		do
+			set_max_keep_alive_requests (-1)
+		end
+
+	disable_persistent_connection
+		do
+			set_max_keep_alive_requests (0)
+		end
+
 	set_is_secure (b: BOOLEAN)
 			-- Set secured connection enabled to `b'.
 			-- i.e if connection is using SSL/TLS.