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EWF/examples/rest/restbucks_CRUD/src/resource/order_handler.e

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note
description: "{ORDER_HANDLER} handle the resources that we want to expose"
author: ""
date: "$Date$"
revision: "$Revision$"
class
ORDER_HANDLER
inherit
WSF_URI_TEMPLATE_HANDLER
WSF_RESOURCE_HANDLER_HELPER
redefine
do_get,
do_post,
do_put,
do_delete
end
SHARED_RESTBUCKS_API
REFACTORING_HELPER
WSF_SELF_DOCUMENTED_HANDLER
create
make
feature {NONE} -- Initialization
make (a_orderid_path_parameter_name: READABLE_STRING_GENERAL; a_router: WSF_ROUTER)
do
orderid_path_parameter_name := a_orderid_path_parameter_name
end
orderid_path_parameter_name: READABLE_STRING_GENERAL
feature -- Execute
execute (req: WSF_REQUEST; res: WSF_RESPONSE)
-- Execute request handler
do
execute_methods (req, res)
end
feature -- Request parameters
order_id_from_request (req: WSF_REQUEST): detachable STRING_8
do
if attached {WSF_STRING} req.path_parameter (orderid_path_parameter_name) as p_id then
Result := p_id.url_encoded_value -- the ORDER id has to be valid STRING 8 value.
end
end
feature -- API DOC
api_doc : STRING = "URI:/order METHOD: POST%N URI:/order/{orderid} METHOD: GET, PUT, DELETE%N"
feature -- Documentation
mapping_documentation (m: WSF_ROUTER_MAPPING; a_request_methods: detachable WSF_REQUEST_METHODS): WSF_ROUTER_MAPPING_DOCUMENTATION
do
create Result.make (m)
if a_request_methods /= Void then
if a_request_methods.has_method_post then
Result.add_description ("URI:/order METHOD: POST")
elseif
a_request_methods.has_method_get
or a_request_methods.has_method_put
or a_request_methods.has_method_delete
then
Result.add_description ("URI:/order/{orderid} METHOD: GET, PUT, DELETE")
end
end
end
feature -- HTTP Methods
do_get (req: WSF_REQUEST; res: WSF_RESPONSE)
-- <Precursor>
do
if
attached order_id_from_request (req) as l_id and then
attached order (l_id) as l_order
then
if is_conditional_get (req, l_order) then
handle_resource_not_modified_response ("The resource" + req.percent_encoded_path_info + " does not change", req, res)
else
compute_response_get (req, res, l_order)
end
else
handle_resource_not_found_response ("The following resource" + req.percent_encoded_path_info + " is not found ", req, res)
end
end
is_conditional_get (req : WSF_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_string_variable ("HTTP_IF_NONE_MATCH") as if_none_match then
create etag_util
if if_none_match.same_string (etag_util.md5_digest (l_order.out).as_string_32) then
Result := True
end
end
end
compute_response_get (req: WSF_REQUEST; res: WSF_RESPONSE; l_order: ORDER)
local
l_msg : STRING
do
res.header.put_content_type_application_json
if attached order_to_json (l_order) as jv then
l_msg := jv.representation
res.header.put_content_length (l_msg.count)
res.header.put_utc_date (create {DATE_TIME}.make_now_utc)
res.header.add_header ("etag:" + order_etag (l_order))
res.set_status_code ({HTTP_STATUS_CODE}.ok)
res.put_string (l_msg)
end
end
do_put (req: WSF_REQUEST; res: WSF_RESPONSE)
-- Updating a resource with PUT
-- A successful PUT request will not create a new resource, instead it will
-- change the state of the resource identified by the current uri.
-- If success we response with 200 and the updated order.
-- 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.
do
if attached order_id_from_request (req) as l_id then
if has_order (l_id) then
if attached order_from_request (req) as l_order then
if l_order.has_id and then not l_id.same_string (l_order.id) then
-- If request input data define an order id different from the one in request path!
handle_resource_conflict_response ("ERROR: conflict between the url defining order id [" + l_id + "] and request data of order with id [" + l_order.id + "]!", req, res)
else
l_order.set_id (l_id)
if is_valid_to_update (l_order) then
if is_conditional_put (req, l_order) then
update_order (l_order)
compute_response_put (req, res, l_order)
else
handle_precondition_fail_response ("ERROR", req, res)
end
else
--| TODO: build message explaining the conflict to the client!
--| FIXME: Here we need to define the Allow methods
handle_resource_conflict_response ("ERROR: order could not be updated!", req, res)
end
end
else
handle_bad_request_response ("ERROR: invalid request input data!", req, res)
end
else
handle_bad_request_response ("ERROR: Order [" + l_id.out + "] was not found!", req, res)
end
else
handle_bad_request_response ("ERROR: Missing ORDER id information!", req, res)
end
end
is_conditional_put (req: WSF_REQUEST; a_order: ORDER): BOOLEAN
-- Check if If-Match is present and then if `a_order` is matching that etag,
-- if etag from `a_order` is unchanged, return True.
do
if attached req.meta_string_variable ("HTTP_IF_MATCH") as if_match then
if attached order (a_order.id) as l_order then
if if_match.same_string (order_etag (l_order)) then
Result := True
end
else
Result := False
end
else
Result := True
end
end
compute_response_put (req: WSF_REQUEST; res: WSF_RESPONSE; l_order : ORDER)
do
res.header.put_content_type_application_json
res.header.put_utc_date (create {DATE_TIME}.make_now_utc)
res.header.add_header ("etag:" + order_etag (l_order))
if attached order_to_json (l_order) as jv then
res.header.put_content_length (jv.representation.count)
res.set_status_code ({HTTP_STATUS_CODE}.ok)
res.put_string (jv.representation)
end
end
do_delete (req: WSF_REQUEST; res: WSF_RESPONSE)
-- Here we use DELETE to cancel an order, if that order is in state where
-- it can still be canceled.
-- 200 if is ok
-- 404 Resource not found
-- 405 if consumer and service's view of the resouce state is inconsisent
-- 500 if we have an internal server error
do
if
attached order_id_from_request (req) as l_id and then
attached order (l_id) as l_order
then
if is_valid_to_delete (l_order) then
delete_order (l_order)
compute_response_delete (req, res)
else
--| FIXME: Here we need to define the Allow methods
handle_method_not_allowed_response (req.percent_encoded_path_info + "%N Conflict while trying to delete the order! The order could not be deleted in the current state!", req, res)
end
else
handle_resource_not_found_response ("Order not found", req, res)
end
end
compute_response_delete (req: WSF_REQUEST; res: WSF_RESPONSE)
do
res.header.put_content_type_application_json
res.header.put_utc_date (create {DATE_TIME}.make_now_utc)
res.set_status_code ({HTTP_STATUS_CODE}.no_content)
end
do_post (req: WSF_REQUEST; res: WSF_RESPONSE)
-- Here the convention is the following.
-- POST is used for creation and the server determines the URI
-- of the created resource.
-- If the request post is SUCCESS, the server will create the order and will response with
-- HTTP_RESPONSE 201 CREATED, the Location header will contains the newly created order's URI
-- if the request post is not SUCCESS, the server will response with
-- HTTP_RESPONSE 400 BAD REQUEST, the client send a bad request
-- HTTP_RESPONSE 500 INTERNAL_SERVER_ERROR, when the server can deliver the request
do
if attached order_from_request (req) as l_order then
submit_order (l_order)
compute_response_post (req, res, l_order)
else
handle_bad_request_response ("ERROR: invalid request input data!", req, res)
end
end
compute_response_post (req: WSF_REQUEST; res: WSF_RESPONSE; l_order : ORDER)
local
l_msg : STRING
do
res.header.put_content_type_application_json
if attached order_to_json (l_order) as jv then
l_msg := jv.representation
res.header.put_content_length (l_msg.count)
res.header.put_location (req.absolute_script_url (req.request_uri + "/" + l_order.id))
res.header.put_utc_date (create {DATE_TIME}.make_now_utc)
res.set_status_code ({HTTP_STATUS_CODE}.created)
res.put_string (l_msg)
end
end
feature {NONE} -- URI helper methods
get_order_id_from_path (a_path: READABLE_STRING_32): READABLE_STRING_32
do
Result := a_path.split ('/').at (3)
end
feature {NONE} -- Implementation Repository Layer
order_etag (a_order: ORDER): STRING_8
local
etag_utils: ETAG_UTILS
do
create etag_utils
Result := etag_utils.md5_digest (a_order.hash_code.out + a_order.revision.out)
end
is_valid_to_delete (a_order: ORDER): BOOLEAN
-- Is the order identified by `a_id' in a state whre it can still be deleted?
do
if attached order (a_order.id) as l_order then
if api.is_state_valid_to_update (l_order.status) then
Result := True
end
end
end
is_valid_to_update (a_order: ORDER): BOOLEAN
-- Check if there is a conflict while trying to update the order.
do
if attached order (a_order.id) as l_existing_order then
if
api.is_state_valid_to_update (l_existing_order.status) and then
api.is_valid_status_state (a_order.status) and then
api.is_valid_transition (l_existing_order, a_order.status)
then
Result := True
end
end
end
order_from_request (req: WSF_REQUEST): detachable ORDER
-- extract an object Order from the request,
-- or Void if the request is invalid.
local
l_data: STRING
do
create l_data.make (req.content_length_value.to_integer_32)
req.read_input_data_into (l_data)
Result := order_from_request_input_data (l_data)
end
order_from_request_input_data (a_data: READABLE_STRING_8): detachable ORDER
-- extract an object Order from the request,
-- or Void if the request is invalid.
local
parser : JSON_PARSER
do
create parser.make_with_string (a_data)
parser.parse_content
if
parser.is_valid and then
attached parser.parsed_json_value as jv
then
Result := order_from_json (jv)
end
end
feature {NONE} -- Conversion
order_to_json (obj: ORDER): JSON_OBJECT
local
j_item: JSON_OBJECT
ja: JSON_ARRAY
do
create Result.make_with_capacity (4)
Result.put_string (obj.id, id_key)
if attached obj.location as loc then
Result.put_string (loc, location_key)
end
Result.put_string (obj.status, status_key)
if attached obj.items as l_items and then not l_items.is_empty then
create ja.make (l_items.count)
Result.put (ja, items_key)
across
l_items as ic
loop
if attached {ORDER_ITEM} ic.item as l_item then
create j_item.make_with_capacity (4)
j_item.put_string (l_item.name, name_key)
j_item.put_string (l_item.size, size_key)
j_item.put_integer (l_item.quantity, quantity_key)
j_item.put_string (l_item.option, option_key)
ja.extend (j_item)
end
end
end
end
order_from_json (a_json: JSON_VALUE): detachable ORDER
local
l_status: detachable STRING_32
q: NATURAL_8
is_valid_from_json: BOOLEAN
l_name, l_size, l_option: detachable READABLE_STRING_32
do
is_valid_from_json := True
if attached {JSON_OBJECT} a_json as jobj then
-- Either new order (i.e no id and no status)
-- or an existing order with `id` and `status` (could be Void, thus use default).
if attached {JSON_STRING} jobj.item (status_key) as j_status then
l_status := j_status.unescaped_string_32
end
if
attached {JSON_STRING} jobj.item (id_key) as j_id
then
-- Note: the id has to be valid string 8 value!
create Result.make (j_id.unescaped_string_8, l_status)
elseif attached {JSON_NUMBER} jobj.item (id_key) as j_id then
-- Be flexible and accept json number as id.
create Result.make (j_id.integer_64_item.out, l_status)
else
create Result.make_empty
if l_status /= Void then
Result.set_status (l_status)
end
end
if attached {JSON_STRING} jobj.item (location_key) as j_location then
Result.set_location (j_location.unescaped_string_32)
end
if attached {JSON_ARRAY} jobj.item (items_key) as j_items then
across
j_items as ic
loop
if attached {JSON_OBJECT} ic.item as j_item then
if
attached {JSON_NUMBER} j_item.item (quantity_key) as j_quantity and then
j_quantity.integer_64_item < {NATURAL_8}.Max_value
then
q := j_quantity.integer_64_item.to_natural_8
else
q := 0
end
if
attached {JSON_STRING} j_item.item (name_key) as j_name and then
attached {JSON_STRING} j_item.item (size_key) as j_size and then
attached {JSON_STRING} j_item.item (option_key) as j_option
then
l_name := j_name.unescaped_string_32
l_size := j_size.unescaped_string_32
l_option := j_option.unescaped_string_32
if is_valid_item_customization (l_name, l_size, l_option, q) then
Result.add_item (create {ORDER_ITEM}.make (l_name, l_size, l_option, q))
else
is_valid_from_json := False
end
else
is_valid_from_json := False
end
end
end
end
if not is_valid_from_json or Result.items.is_empty then
Result := Void
end
else
is_valid_from_json := a_json = Void or else attached {JSON_NULL} a_json
Result := Void
end
end
is_valid_item_customization (name: READABLE_STRING_GENERAL; size: READABLE_STRING_GENERAL; option: READABLE_STRING_GENERAL; quantity: NATURAL_8): BOOLEAN
local
ic: ORDER_ITEM_VALIDATION
do
create ic
Result := ic.is_valid_coffee_type (name) and
ic.is_valid_milk_type (option) and
ic.is_valid_size_option (size) and
quantity > 0
end
id_key: STRING = "id"
location_key: STRING = "location"
status_key: STRING = "status"
items_key: STRING = "items"
name_key: STRING = "name"
size_key: STRING = "size"
quantity_key: STRING = "quantity"
option_key: STRING = "option"
note
copyright: "2011-2017, Javier Velilla and others"
license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
end