Update Restbucks example: Conditional GET, PUT.

Added a response method to support resource not
modified.
Added a ETAG_UTILS class to calcule md5_digest.
Added ext libs eel and eapml.

.gitmodules

@@ -10,3 +10,9 @@
 [submodule "ext/ise_library/curl"]
 	path = ext/ise_library/curl
 	url = http://github.com/EiffelSoftware/mirror-Eiffel-cURL.git
+[submodule "ext/crypto/eel"]
+	path = ext/crypto/eel
+	url = http://github.com/Eiffel-World/eel.git
+[submodule "ext/crypto/eapml"]
+	path = ext/crypto/eapml
+	url = http://github.com/Eiffel-World/eapml.git

examples/restbucks/restbucks-safe.ecf

@@ -16,8 +16,9 @@
 		<library name="default_nino" location="..\..\library\server\ewsgi\default\ewsgi_nino-safe.ecf" readonly="false"/>
 		<library name="encoder" location="..\..\library\text\encoder\encoder-safe.ecf" readonly="false"/>
 		<library name="ewsgi" location="..\..\library\server\ewsgi\ewsgi-safe.ecf" readonly="false"/>
-		<library name="json" location="..\..\ext\text\json\library\json-safe.ecf" readonly="false"/>
 		<library name="http" location="..\..\library\protocol\http\http-safe.ecf" readonly="false"/>
+		<library name="json" location="..\..\ext\text\json\library\json-safe.ecf" readonly="false"/>
+		<library name="eel" location="..\..\ext\crypto\eel\eel-safe.ecf" readonly="false"/>
 		<library name="router" location="..\..\library\server\request\router\router-safe.ecf" readonly="false"/>
 		<library name="uri_template" location="..\..\library\protocol\uri_template\uri_template-safe.ecf" readonly="false"/>
 		<cluster name="src" location="src\" recursive="true"/>

examples/restbucks/src/domain/order.e

@@ -86,6 +86,9 @@ feature -- Etag
 			Result := hash_code.out + revision.out
 		end
 
+
+feature -- Output
+
 feature -- Report
 
 	hash_code: INTEGER_32

examples/restbucks/src/resource/order_handler.e

@@ -40,25 +40,48 @@ feature -- HTTP Methods
 			-- 200 OK, and a representation of the order
 			-- If the GET request is not SUCCESS, we response with
 			-- 404 Resource not found
+			-- If is a Condition GET and the resource does not change we send a
+			-- 304, Resource not modifed
 		local
 			id :  STRING
 		do
 			if attached req.orig_path_info as orig_path then
 				id := get_order_id_from_path (orig_path)
 				if attached retrieve_order (id) as l_order then
-					compute_response_get (ctx, req, res, l_order)
+					if is_conditional_get (req, l_order) then
+						handle_resource_not_modified_response ("The resource" + orig_path + "does not change", ctx, req, res)
+					else
+						compute_response_get (ctx, req, res, l_order)
+					end
 				else
 					handle_resource_not_found_response ("The following resource" + orig_path + " is not found ", ctx, req, res)
 				end
 			end
 		end
 
+	is_conditional_get (req : WGI_REQUEST; l_order : ORDER) : BOOLEAN
+		-- Check if If-None-Match is present and then if there is a representation that has that etag
+		-- if the representation hasn't changed, we return TRUE
+		-- then the response is a 304 with no entity body returned.
+		local
+			etag_util : ETAG_UTILS
+		do
+				if attached req.meta_variable ("HTTP_IF_NONE_MATCH") as if_none_match then
+						create etag_util
+						if if_none_match.as_string.same_string (etag_util.md5_digest (l_order.out).as_string_32) then
+							Result := True
+						end
+				end
+		end
+
 	compute_response_get (ctx: C; req: WGI_REQUEST; res: WGI_RESPONSE_BUFFER; l_order : ORDER)
 		local
 			h: EWF_HEADER
 			l_msg : STRING
+			etag_utils : ETAG_UTILS
 		do
 			create h.make
+			create etag_utils
 			h.put_status ({HTTP_STATUS_CODE}.ok)
 			h.put_content_type_application_json
 			if attached {JSON_VALUE} json.value (l_order) as jv then
@@ -67,6 +90,7 @@ feature -- HTTP Methods
 				if attached req.request_time as time then
 					h.add_header ("Date:" + time.formatted_out ("ddd,[0]dd mmm yyyy [0]hh:[0]mi:[0]ss.ff2") + " GMT")
 				end
+				h.add_header ("etag:" + etag_utils.md5_digest (l_order.out))
 				res.set_status_code ({HTTP_STATUS_CODE}.ok)
 				res.write_headers_string (h.string)
 				res.write_string (l_msg)
@@ -81,6 +105,8 @@ feature -- HTTP Methods
 		-- 404 if the order is not found
 		-- 400 in case of a bad request
 		-- 500 internal server error
+		-- If the request is a Conditional PUT, and it does not mat we response
+		-- 415, precondition failed.
 		local
 			l_post: STRING
 			l_order : detachable ORDER
@@ -90,8 +116,12 @@ feature -- HTTP Methods
 			l_order := extract_order_request(l_post)
 			if  l_order /= Void and then db_access.orders.has_key (l_order.id) then
 				if is_valid_to_update(l_order) then
-					update_order( l_order)
+					if is_conditional_put (req, l_order) then
-					compute_response_put (ctx, req, res, l_order)
+						update_order( l_order)
+						compute_response_put (ctx, req, res, l_order)
+					else
+						handle_precondition_fail_response ("", ctx, req, res)
+					end
 				else
 					--| FIXME: Here we need to define the Allow methods
 					handle_resource_conflict_response (l_post +"%N There is conflict while trying to update the order, the order could not be update in the current state", ctx, req, res)
@@ -101,13 +131,34 @@ feature -- HTTP Methods
 			end
 		end
 
+	is_conditional_put (req : WGI_REQUEST; order : ORDER) : BOOLEAN
+		-- Check if If-Match is present and then if there is a representation that has that etag
+		-- if the representation hasn't changed, we return TRUE
+		local
+			etag_util : ETAG_UTILS
+		do
+			if attached retrieve_order (order.id) as l_order then
+				if attached req.meta_variable ("HTTP_IF_MATCH") as if_match then
+						create etag_util
+						if if_match.as_string.same_string (etag_util.md5_digest (l_order.out).as_string_32) then
+							Result := True
+						end
+				else
+					Result := True
+				end
+			end
+		end
+
+
 	compute_response_put (ctx: C; req: WGI_REQUEST; res: WGI_RESPONSE_BUFFER; l_order : ORDER)
 		local
 			h: EWF_HEADER
 			joc : JSON_ORDER_CONVERTER
+			etag_utils : ETAG_UTILS
 		do
 			create h.make
 			create joc.make
+			create etag_utils
 			json.add_converter(joc)
 
 			create h.make
@@ -116,6 +167,7 @@ feature -- HTTP Methods
 			if attached req.request_time as time then
 				h.add_header ("Date:" +time.formatted_out ("ddd,[0]dd mmm yyyy [0]hh:[0]mi:[0]ss.ff2") + " GMT")
 			end
+			h.add_header ("etag:" + etag_utils.md5_digest (l_order.out))
 			if attached {JSON_VALUE} json.value (l_order) as jv then
 				h.put_content_length (jv.representation.count)
 				res.set_status_code ({HTTP_STATUS_CODE}.ok)
@@ -133,7 +185,6 @@ feature -- HTTP Methods
 		-- 500 if we have an internal server error
 		local
 			id: STRING
-			h : EWF_HEADER
 		do
 			if  attached req.orig_path_info as orig_path then
 				id := get_order_id_from_path (orig_path)

library/server/request/router/src/misc/request_resource_handler_helper.e

@@ -182,6 +182,25 @@ feature -- Handle responses
 			res.write_string (a_description)
 		end
 
+
+	handle_precondition_fail_response (a_description:STRING; ctx: C; req: WGI_REQUEST; res: WGI_RESPONSE_BUFFER )
+		local
+			h : EWF_HEADER
+		do
+			create h.make
+			h.put_status ({HTTP_STATUS_CODE}.precondition_failed)
+			if attached ctx.request_content_type (supported_content_types) as l_content_type then
+				h.put_content_type (l_content_type)
+			else
+				h.put_content_type ("*/*")
+			end
+			h.put_content_length (a_description.count)
+			h.put_current_date
+			res.set_status_code ({HTTP_STATUS_CODE}.precondition_failed)
+			res.write_headers_string (h.string)
+			res.write_string (a_description)
+		end
+
 	handle_internal_server_error (a_description:STRING; ctx: C; req: WGI_REQUEST; res: WGI_RESPONSE_BUFFER )
 		local
 			h : EWF_HEADER
@@ -239,6 +258,26 @@ feature -- Handle responses
 		end
 
 
+	handle_resource_not_modified_response (a_description:STRING; ctx: C; req: WGI_REQUEST; res: WGI_RESPONSE_BUFFER)
+		local
+			h : EWF_HEADER
+		do
+			res.flush
+			create h.make
+			h.put_status ({HTTP_STATUS_CODE}.not_modified)
+			if attached ctx.request_content_type (supported_content_types) as l_content_type then
+				h.put_content_type (l_content_type)
+			else
+				h.put_content_type ("*/*")
+			end
+			h.put_content_length (a_description.count)
+			h.put_current_date
+			res.set_status_code ({HTTP_STATUS_CODE}.not_modified)
+			res.write_headers_string (h.string)
+			res.write_string (a_description)
+		end
+
+
 	handle_resource_conflict_response (a_description:STRING; ctx: C; req: WGI_REQUEST; res: WGI_RESPONSE_BUFFER)
 		local
 			h : EWF_HEADER