Further use of constants for execution variables

examples/restbucksCRUD/src/resource/order_handler.e

@@ -28,6 +28,18 @@ create
 
 	make_with_router
 
+
+feature -- Execution variables
+
+	Order_execution_variable: STRING = "ORDER"
+			-- Execution variable used by application
+
+	Generated_content_execution_variable: STRING = "GENERATED_CONTENT"
+			-- Execution variable used by application
+
+	Extracted_order_execution_variable: STRING = "EXTRACTED_ORDER"
+			-- Execution variable used by application
+
 feature -- Documentation
 
 	description: READABLE_STRING_GENERAL
@@ -87,13 +99,6 @@ feature -- Access
 			Result.compare_objects
 		end
 
-	previous_location (req: WSF_REQUEST): LIST [URI]
-			-- Previous location(s) for resource named by `req';
-		do
-			-- precondition is never met but we need a non-void Result to satisfy the compiler in Void-safe mode:
-			create {LINKED_LIST [URI]} Result.make
-		end
-
 	age (req: WSF_REQUEST): NATURAL
 			-- Maximum age in seconds before response to `req` is considered stale;
 			-- This is used to generate a Cache-Control: max-age header.
@@ -158,7 +163,7 @@ feature -- Access
 			l_etag_utils: ETAG_UTILS
 		do
 			create l_etag_utils
-			if attached {ORDER} req.execution_variable ("ORDER") as l_order then
+			if attached {ORDER} req.execution_variable (Order_execution_variable) as l_order then
 				Result := l_etag_utils.md5_digest (l_order.out)
 			end
 		end
@@ -175,7 +180,7 @@ feature -- Measurement
 	content_length (req: WSF_REQUEST): NATURAL
 			-- Length of entity-body of the response to `req'
 		do
-			check attached {READABLE_STRING_8} req.execution_variable ("GENERATED_CONTENT") as l_response then
+			check attached {READABLE_STRING_8} req.execution_variable (Generated_content_execution_variable) as l_response then
 					-- postcondition generated_content_set_for_get_head of `ensure_content_available'
 					-- We only call this for GET/HEAD in this example.
 				Result := l_response.count.as_natural_32
@@ -201,7 +206,7 @@ feature -- Execution
 	check_resource_exists (req: WSF_REQUEST; a_helper: WSF_METHOD_HELPER)
 			-- Call `a_helper.set_resource_exists' to indicate that `req.path_translated'
 			--  is the name of an existing resource.
-			-- We also put the order into `req.execution_variable ("ORDER")' for GET or HEAD responses.
+			-- We also put the order into `req.execution_variable (Order_execution_variable)' for GET or HEAD responses.
 		local
 			l_id: STRING
 		do
@@ -216,14 +221,14 @@ feature -- Execution
 					if req.is_get_head_request_method then
 						check attached db_access.orders.item (l_id) as l_order then
 								-- postcondition `item_if_found' of `has_key'
-							req.set_execution_variable ("ORDER", l_order)
+							req.set_execution_variable (Order_execution_variable, l_order)
 						end
 					end
 				end
 			end
 		ensure then
 			order_saved_only_for_get_head: req.is_get_head_request_method =
-				attached {ORDER} req.execution_variable ("ORDER")
+				attached {ORDER} req.execution_variable (Order_execution_variable)
 		end
 
 feature -- GET/HEAD content
@@ -234,27 +239,27 @@ feature -- GET/HEAD content
 			--  for a subsequent call to `content'.
 			-- If chunked, only the first chunk will be made available to `next_chunk'. If chunk extensions
 			--  are used, then this will also generate the chunk extension for the first chunk.
-			-- We save the text in `req.execution_variable ("GENERATED_CONTENT")'
+			-- We save the text in `req.execution_variable (Generated_content_execution_variable)'
 			-- We ignore the results of content negotiation, as there is only one possible combination.
 		do
-			check attached {ORDER} req.execution_variable ("ORDER") as l_order then
+			check attached {ORDER} req.execution_variable (Order_execution_variable) as l_order then
 					-- precondition get_or_head and postcondition order_saved_only_for_get_head of `check_resource_exists' and
 				if attached {JSON_VALUE} json.value (l_order) as jv then
-					req.set_execution_variable ("GENERATED_CONTENT", jv.representation)
+					req.set_execution_variable (Generated_content_execution_variable, jv.representation)
 				else
-					req.set_execution_variable ("GENERATED_CONTENT", "")
+					req.set_execution_variable (Generated_content_execution_variable, "")
 				end
 			end
 		ensure then
 			generated_content_set_for_get_head: req.is_get_head_request_method implies
-				 attached {READABLE_STRING_8} req.execution_variable ("GENERATED_CONTENT")
+				 attached {READABLE_STRING_8} req.execution_variable (Generated_content_execution_variable)
 		end
 
 	content (req: WSF_REQUEST): READABLE_STRING_8
 			-- Non-chunked entity body in response to `req';
 			-- We only call this for GET/HEAD in this example.
 		do
-			check attached {READABLE_STRING_8} req.execution_variable ("GENERATED_CONTENT") as l_response then
+			check attached {READABLE_STRING_8} req.execution_variable (Generated_content_execution_variable) as l_response then
 					-- postcondition generated_content_set_for_get_head of `ensure_content_available'
 				Result := l_response
 			end
@@ -307,14 +312,14 @@ feature -- DELETE
 feature -- PUT/POST
 
 	is_entity_too_large (req: WSF_REQUEST): BOOLEAN
-			-- Is the entity stored in `req.execution_variable ("REQUEST_ENTITY")' too large for the application?
+			-- Is the entity stored in `req.execution_variable (Request_entity_execution_variable)' too large for the application?
 		do
 			-- No. We don't care for this example.
 		end
 
 	check_content_headers (req: WSF_REQUEST)
 			-- Check we can support all content headers on request entity.
-			-- Set `req.execution_variable ("CONTENT_CHECK_CODE")' to {NATURAL} zero if OK, or 415 or 501 if not.
+			-- Set `req.execution_variable (Content_check_code_execution_variable)' to {NATURAL} zero if OK, or 415 or 501 if not.
 		do
 			-- We don't bother for this example. Note that this is equivalent to setting zero.
 		end
@@ -331,7 +336,7 @@ feature -- PUT/POST
 			-- Create new resource in response to a POST request.
 			-- Implementor must set error code of 200 OK or 204 No Content or 303 See Other or 500 Server Error.
 		do
-			if attached {ORDER} req.execution_variable ("EXTRACTED_ORDER") as l_order then
+			if attached {ORDER} req.execution_variable (Extracted_order_execution_variable) as l_order then
 				save_order (l_order)
 				compute_response_post (req, res, l_order)
 			else
@@ -341,16 +346,16 @@ feature -- PUT/POST
 
 	check_conflict (req: WSF_REQUEST; res: WSF_RESPONSE)
 			-- Check we can support all content headers on request entity.
-			-- Set `req.execution_variable ("CONFLICT_CHECK_CODE")' to {NATURAL} zero if OK, or 409 if not.
+			-- Set `req.execution_variable (Conflict_check_code_execution_variable)' to {NATURAL} zero if OK, or 409 if not.
 			-- In the latter case, write the full error response to `res'.
 		do
-			if attached {ORDER} req.execution_variable ("EXTRACTED_ORDER") as l_order then
+			if attached {ORDER} req.execution_variable (Extracted_order_execution_variable) as l_order then
 				if not is_valid_to_update (l_order)	then
-					req.set_execution_variable ("CONFLICT_CHECK_CODE", {NATURAL} 409)
+					req.set_execution_variable (Conflict_check_code_execution_variable, {NATURAL} 409)
 					handle_resource_conflict_response (l_order.out +"%N There is conflict while trying to update the order, the order could not be update in the current state", req, res)
 				end
 			else
-				req.set_execution_variable ("CONFLICT_CHECK_CODE", {NATURAL} 409)
+				req.set_execution_variable (Conflict_check_code_execution_variable, {NATURAL} 409)
 				--| This ought to be a 500, as if attached should probably be check attached. But as yet I lack a proof.
 				handle_resource_conflict_response ("There is conflict while trying to update the order, the order could not be update in the current state", req, res)
 			end
@@ -358,31 +363,31 @@ feature -- PUT/POST
 
 	check_request (req: WSF_REQUEST; res: WSF_RESPONSE)
 			-- Check that the request entity is a valid request.
-			-- The entity is available as `req.execution_variable ("REQUEST_ENTITY")'.
+			-- The entity is available as `req.execution_variable (Conflict_check_code_execution_variable)'.
-			-- Set `req.execution_variable ("REQUEST_CHECK_CODE")' to {NATURAL} zero if OK, or 400 if not.
+			-- Set `req.execution_variable (Request_check_code_execution_variable)' to {NATURAL} zero if OK, or 400 if not.
 			-- In the latter case, write the full error response to `res'.
 		local
 			l_order: detachable ORDER
 			l_id: STRING
 		do
-			if attached {READABLE_STRING_8} req.execution_variable ("REQUEST_ENTITY") as l_request then
+			if attached {READABLE_STRING_8} req.execution_variable (Request_entity_execution_variable) as l_request then
 				l_order := extract_order_request (l_request)
 				if req.is_put_request_method then
 					l_id := order_id_from_request (req)
 					if l_order /= Void  and then db_access.orders.has_key (l_id) then
 						l_order.set_id (l_id)
-						req.set_execution_variable ("REQUEST_CHECK_CODE", {NATURAL} 0)
+						req.set_execution_variable (Request_check_code_execution_variable, {NATURAL} 0)
-						req.set_execution_variable ("EXTRACTED_ORDER", l_order)
+						req.set_execution_variable (Extracted_order_execution_variable, l_order)
 					else
-						req.set_execution_variable ("REQUEST_CHECK_CODE", {NATURAL} 400)
+						req.set_execution_variable (Request_check_code_execution_variable, {NATURAL} 400)
 						handle_bad_request_response (l_request +"%N is not a valid ORDER, maybe the order does not exist in the system", req, res)
 					end
 				else
-					req.set_execution_variable ("REQUEST_CHECK_CODE", {NATURAL} 0)
+					req.set_execution_variable (Request_check_code_execution_variable, {NATURAL} 0)
-					req.set_execution_variable ("EXTRACTED_ORDER", l_order)
+					req.set_execution_variable (Extracted_order_execution_variable, l_order)
 				end
 			else
-				req.set_execution_variable ("REQUEST_CHECK_CODE", {NATURAL} 400)
+				req.set_execution_variable (Request_check_code_execution_variable, {NATURAL} 400)
 				handle_bad_request_response ("Request is not a valid ORDER", req, res)
 			end
 		end
@@ -391,7 +396,7 @@ feature -- PUT/POST
 			-- Perform the update requested in `req'.
 			-- Write a response to `res' with a code of 204 or 500.
 		do
-			if attached {ORDER} req.execution_variable ("EXTRACTED_ORDER") as l_order then
+			if attached {ORDER} req.execution_variable (Extracted_order_execution_variable) as l_order then
 				update_order (l_order)
 				compute_response_put (req, res, l_order)
 			else

library/server/wsf/router/wsf_method_helper.e

@@ -12,7 +12,7 @@ deferred class WSF_METHOD_HELPER
 inherit
 
 	HTTP_STATUS_CODE_MESSAGES
-	
+
 	SHARED_HTML_ENCODER
 		export {NONE} all end
 
@@ -58,7 +58,7 @@ feature -- Basic operations
 					l_locs := a_handler.previous_location (req)
 					handle_redirection_error (req, res, l_locs, {HTTP_STATUS_CODE}.found)
 				else
-					check attached {HTTP_HEADER} req.execution_variable ("NEGOTIATED_HTTP_HEADER") as h then
+					check attached {HTTP_HEADER} req.execution_variable (a_handler.Negotiated_http_header_execution_variable) as h then
 						-- postcondition header_attached of `handle_content_negotiation'
 						h.put_content_type_text_plain
 						h.put_current_date
@@ -68,7 +68,7 @@ feature -- Basic operations
 					end
 				end
 			else
-				check attached {HTTP_HEADER} req.execution_variable ("NEGOTIATED_HTTP_HEADER") as h then
+				check attached {HTTP_HEADER} req.execution_variable (a_handler.Negotiated_http_header_execution_variable) as h then
 						-- postcondition header_attached of `handle_content_negotiation'
 					h.put_content_type_text_plain
 					h.put_current_date
@@ -140,7 +140,7 @@ feature -- Basic operations
 						end
 					end
 					if not l_failed then
-						check attached {HTTP_HEADER} req.execution_variable ("NEGOTIATED_HTTP_HEADER") as h then
+						check attached {HTTP_HEADER} req.execution_variable (a_handler.Negotiated_http_header_execution_variable) as h then
 								-- postcondition header_attached of `handle_content_negotiation'
 							send_response (req, res, a_handler, h, False)
 						end
@@ -154,7 +154,7 @@ feature -- Content negotiation
 	handle_content_negotiation (req: WSF_REQUEST; res: WSF_RESPONSE; a_handler: WSF_SKELETON_HANDLER)
 			-- Negotiate acceptable content for, then write, response requested by `req' into `res'.
 			-- Policy routines are available in `a_handler'.
-			-- 
+			--
 			-- Either a 406 Not Acceptable error is sent, or upto four execution variables may be set on `req':
 			-- "NEGOTIATED_MEDIA_TYPE"
 			-- "NEGOTIATED_LANGUAGE"
@@ -290,7 +290,7 @@ feature {NONE} -- Implementation
 					l_chunk := a_handler.next_chunk (req)
 					res.put_chunk (l_chunk.a_chunk, l_chunk.a_extension)
 				else
-					write_error_response (req, res)					
+					write_error_response (req, res)
 				end
 			end
 			if a_handler.finished (req) then
@@ -366,7 +366,7 @@ feature {NONE} -- Implementation
 
 feature -- Errors
 
-	
+
 feature -- Error reporting
 
 	write_error_response (req: WSF_REQUEST; res: WSF_RESPONSE)
@@ -439,7 +439,7 @@ feature -- Error reporting
 					s.append ("<div id=%"footer%"></div>")
 					s.append ("</body>%N")
 					s.append ("</html>%N")
-					
+
 					h.put_content_type_text_html
 				else
 					s := "Error " + a_status_code.out + " (" + l_msg + "): "
@@ -566,7 +566,7 @@ feature -- Error reporting
 			res.set_status_code ({HTTP_STATUS_CODE}.not_implemented)
 			res.put_header_lines (h)
 		end
-	
+
 	handle_request_entity_too_large (req: WSF_REQUEST; res: WSF_RESPONSE; a_handler: WSF_SKELETON_HANDLER)
 			-- Write a Request Entity Too Large response for `req' to `res'.
 		require

library/server/wsf/router/wsf_post_helper.e

@@ -22,7 +22,7 @@ feature -- Basic operations
 			-- Policy routines are available in `a_handler'.
 		do
 			if a_handler.allow_post_to_missing_resource (req) then
-				check attached {HTTP_HEADER} req.execution_variable ("NEGOTIATED_HTTP_HEADER") as h then
+				check attached {HTTP_HEADER} req.execution_variable (a_handler.Negotiated_http_header_execution_variable) as h then
 						-- postcondition header_attached of `handle_content_negotiation'
 					send_response (req, res, a_handler, h, True)
 				end

library/server/wsf/router/wsf_previous_policy.e

@@ -43,10 +43,11 @@ feature -- Access
 			req_attached: req /= Void
 			previously_existed: resource_previously_existed (req)
 			moved: resource_moved_permanently (req) or resource_moved_temporarily (req)
-		deferred
+		do
+			create {LINKED_LIST [URI]} Result.make
 		ensure
 			previous_location_attached: Result /= Void
-			non_empty_list: not Result.empty
+			non_empty_list: not Result.is_empty
 		end
 
 note

library/server/wsf/router/wsf_put_helper.e

@@ -24,7 +24,7 @@ feature -- Basic operations
 			if a_handler.treat_as_moved_permanently (req) then
 				handle_redirection_error (req, res, a_handler.previous_location (req), {HTTP_STATUS_CODE}.moved_permanently)
 			else
-				check attached {HTTP_HEADER} req.execution_variable ("NEGOTIATED_HTTP_HEADER") as h then
+				check attached {HTTP_HEADER} req.execution_variable (a_handler.Negotiated_http_header_execution_variable) as h then
 						-- postcondition header_attached of `handle_content_negotiation'
 					send_response (req, res, a_handler, h, True)
 				end
@@ -68,5 +68,15 @@ feature {NONE} -- Implementation
 				end
 			end
 		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

library/server/wsf/router/wsf_skeleton_handler.e

@@ -30,7 +30,7 @@ feature -- Execution variables
 
 	Negotiated_language_execution_variable: STRING = "NEGOTIATED_LANGUAGE"
 			-- Execution variable set by framework
-		
+
 	Negotiated_charset_execution_variable: STRING = "NEGOTIATED_CHARSET"
 			-- Execution variable set by framework
 
@@ -46,6 +46,15 @@ feature -- Execution variables
 	Request_entity_execution_variable: STRING = "REQUEST_ENTITY"
 			-- Execution variable set by framework
 
+	Conflict_check_code_execution_variable: STRING = "CONFLICT_CHECK_CODE"
+		-- Execution variable set by framework
+
+	Content_check_code_execution_variable: STRING = "CONTENT_CHECK_CODE"
+		-- Execution variable set by framework
+
+	Request_check_code_execution_variable: STRING = "REQUEST_CHECK_CODE"
+		-- Execution variable set by framework
+
 feature -- Access
 
 	is_chunking (req: WSF_REQUEST): BOOLEAN
@@ -329,7 +338,7 @@ feature -- PUT/POST
 		end
 
 	is_entity_too_large (req: WSF_REQUEST): BOOLEAN
-			-- Is the entity stored in `req.execution_variable ("REQUEST_ENTITY")' too large for the application?
+			-- Is the entity stored in `req.execution_variable (Request_entity_execution_variable)' too large for the application?
 		require
 			req_attached: req /= Void
 		deferred
@@ -337,7 +346,7 @@ feature -- PUT/POST
 
 	check_content_headers (req: WSF_REQUEST)
 			-- Check we can support all content headers on request entity.
-			-- Set `req.execution_variable ("CONTENT_CHECK_CODE")' to {NATURAL} zero if OK, or 415 or 501 if not.
+			-- Set `req.execution_variable (Content_check_code_execution_variable)' to {NATURAL} zero if OK, or 415 or 501 if not.
 		require
 			req_attached: req /= Void
 		deferred
@@ -348,7 +357,7 @@ feature -- PUT/POST
 		require
 			req_attached: req /= Void
 		do
-			if attached {NATURAL} req.execution_variable ("CONTENT_CHECK_CODE") as l_code then
+			if attached {NATURAL} req.execution_variable (Content_check_code_execution_variable) as l_code then
 				Result := l_code
 			end
 		end
@@ -375,7 +384,7 @@ feature -- PUT/POST
 
 	check_conflict (req: WSF_REQUEST; res: WSF_RESPONSE)
 			-- Check to see if updating the resource is problematic due to the current state of the resource.
-			-- Set `req.execution_variable ("CONFLICT_CHECK_CODE")' to {NATURAL} zero if OK, or 409 if not.
+			-- Set `req.execution_variable (Conflict_check_code_execution_variable)' to {NATURAL} zero if OK, or 409 if not.
 			-- In the latter case, write the full error response to `res'.
 		require
 			req_attached: req /= Void
@@ -388,15 +397,15 @@ feature -- PUT/POST
 		require
 			req_attached: req /= Void
 		do
-			if attached {NATURAL} req.execution_variable ("CONFLICT_CHECK_CODE") as l_code then
+			if attached {NATURAL} req.execution_variable (Conflict_check_code_execution_variable) as l_code then
 				Result := l_code
 			end
 		end
 
 	check_request (req: WSF_REQUEST; res: WSF_RESPONSE)
 			-- Check that the request entity is a valid request.
-			-- The entity is available as `req.execution_variable ("REQUEST_ENTITY")'.
+			-- The entity is available as `req.execution_variable (Conflict_check_code_execution_variable)'.
-			-- Set `req.execution_variable ("REQUEST_CHECK_CODE")' to {NATURAL} zero if OK, or 400 if not.
+			-- Set `req.execution_variable (Request_check_code_execution_variable)' to {NATURAL} zero if OK, or 400 if not.
 			-- In the latter case, write the full error response to `res'.
 		require
 			req_attached: req /= Void
@@ -410,7 +419,7 @@ feature -- PUT/POST
 		require
 			req_attached: req /= Void
 		do
-			if attached {NATURAL} req.execution_variable ("REQUEST_CHECK_CODE") as l_code then
+			if attached {NATURAL} req.execution_variable (Request_check_code_execution_variable) as l_code then
 				Result := l_code
 			end
 		end