Updated, improved and cleaned RESTbucks example.

Moved it under "rest" subfolder.
This commit is contained in:
2017-02-13 16:23:38 +01:00
parent a44c4d9a16
commit b56aec67a9
35 changed files with 1826 additions and 1419 deletions
@@ -0,0 +1,559 @@
note
description: "{ORDER_HANDLER} handle the resources that we want to expose"
author: ""
date: "$Date$"
revision: "$Revision$"
class ORDER_HANDLER
inherit
WSF_SKELETON_HANDLER
SHARED_RESTBUCKS_API
REFACTORING_HELPER
WSF_RESOURCE_HANDLER_HELPER
rename
execute_options as helper_execute_options,
handle_internal_server_error as helper_handle_internal_server_error
end
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
make_with_router (a_router)
end
orderid_path_parameter_name: READABLE_STRING_GENERAL
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
-- General description for self-generated documentation;
-- The specific URI templates supported will be described automatically
do
Result := "Create, Read, Update or Delete an ORDER."
end
feature -- Access
is_chunking (req: WSF_REQUEST): BOOLEAN
-- Will the response to `req' using chunked transfer encoding?
do
-- No.
end
includes_response_entity (req: WSF_REQUEST): BOOLEAN
-- Does the response to `req' include an entity?
-- Method will be DELETE, POST, PUT or an extension method.
do
Result := False
-- At present, there is no support for this except for DELETE.
end
conneg (req: WSF_REQUEST): SERVER_CONTENT_NEGOTIATION
-- Content negotiatior for all requests
once
create Result.make ({HTTP_MIME_TYPES}.application_json, "en", "UTF-8", "identity")
end
mime_types_supported (req: WSF_REQUEST): LIST [STRING]
-- All values for Accept header that `Current' can serve
do
create {ARRAYED_LIST [STRING]} Result.make_from_array (<<{HTTP_MIME_TYPES}.application_json>>)
Result.compare_objects
end
languages_supported (req: WSF_REQUEST): LIST [STRING]
-- All values for Accept-Language header that `Current' can serve
do
create {ARRAYED_LIST [STRING]} Result.make_from_array (<<"en">>)
Result.compare_objects
end
charsets_supported (req: WSF_REQUEST): LIST [STRING]
-- All values for Accept-Charset header that `Current' can serve
do
create {ARRAYED_LIST [STRING]} Result.make_from_array (<<"UTF-8">>)
Result.compare_objects
end
encodings_supported (req: WSF_REQUEST): LIST [STRING]
-- All values for Accept-Encoding header that `Current' can serve
do
create {ARRAYED_LIST [STRING]} Result.make_from_array (<<"identity">>)
Result.compare_objects
end
max_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.
-- Return 0 to indicate already expired.
-- Return Never_expires to indicate never expires.
do
-- All our responses are considered stale.
end
is_freely_cacheable (req: WSF_REQUEST): BOOLEAN
-- Should the response to `req' be freely cachable in shared caches?
-- If `True', then a Cache-Control: public header will be generated.
do
-- definitely not!
end
private_headers (req: WSF_REQUEST): detachable LIST [READABLE_STRING_8]
-- Header names intended for a single user.
-- If non-Void, then a Cache-Control: private header will be generated.
-- Returning an empty list prevents the entire response from being served from a shared cache.
do
create {ARRAYED_LIST [READABLE_STRING_8]} Result.make (0)
end
non_cacheable_headers (req: WSF_REQUEST): detachable LIST [READABLE_STRING_8]
-- Header names that will not be sent from a cache without revalidation;
-- If non-Void, then a Cache-Control: no-cache header will be generated.
-- Returning an empty list prevents the response being served from a cache
-- without revalidation.
do
create {ARRAYED_LIST [READABLE_STRING_8]} Result.make (0)
end
is_sensitive (req: WSF_REQUEST): BOOLEAN
-- Is the response to `req' of a sensitive nature?
-- If `True' then a Cache-Control: no-store header will be generated.
do
Result := True
-- since it's commercial data.
end
allowed_cross_origins (req: WSF_REQUEST): detachable STRING
-- Value for Access-Control-Allow-Origin header;
-- If supplied, should be a single URI, or the values "*" or "null".
-- This is currently supported only for GET requests, and POSTs that functions as GET.
do
if req.is_get_head_request_method then
Result := "*"
end
end
matching_etag (req: WSF_REQUEST; a_etag: READABLE_STRING_32; a_strong: BOOLEAN): BOOLEAN
-- Is `a_etag' a match for resource requested in `req'?
-- If `a_strong' then the strong comparison function must be used.
local
l_id: STRING
do
l_id := order_id_from_request (req)
if l_id /= Void and then has_order (l_id) then
check attached order (l_id) as l_order then
-- postcondition of `has_key'
Result := a_etag.same_string (order_etag (l_order))
end
end
end
etag (req: WSF_REQUEST): detachable READABLE_STRING_8
-- Optional Etag for `req' in the requested variant
do
if attached {ORDER} req.execution_variable (Order_execution_variable) as l_order then
Result := order_etag (l_order)
end
end
last_modified (req: WSF_REQUEST): detachable DATE_TIME
-- When representation of resource selected in `req' was last modified;
-- SHOULD be set whenever it can reasonably be determined.
do
end
modified_since (req: WSF_REQUEST; a_date_time: DATE_TIME): BOOLEAN
-- Has resource requested in `req' been modified since `a_date_time' (UTC)?
do
-- We don't track this information. It is safe to always say yes.
Result := True
end
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_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
end
end
allow_post_to_missing_resource (req: WSF_REQUEST): BOOLEAN
-- The resource named in `req' does not exist, and this is a POST. Do we allow it?
do
-- No.
end
feature -- Status report
finished (req: WSF_REQUEST): BOOLEAN
-- Has the last chunk been generated for `req'?
do
-- precondition is never met
end
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_execution_variable)' for GET or HEAD responses.
local
l_id: STRING
do
if req.is_post_request_method then
a_helper.set_resource_exists
-- because only /order is defined to this handler for POST
else
-- the request is of the form /order/{orderid}
l_id := order_id_from_request (req)
if l_id /= Void and then has_order (l_id) then
a_helper.set_resource_exists
if req.is_get_head_request_method then
check attached order (l_id) as l_order then
-- postcondition `item_if_found' of `has_key'
req.set_execution_variable (Order_execution_variable, l_order)
end
end
end
end
ensure then
order_saved_only_for_get_head: attached {ORDER} req.execution_variable (Order_execution_variable) implies req.is_get_head_request_method
end
feature -- GET/HEAD content
ensure_content_available (req: WSF_REQUEST)
-- Commence generation of response text (entity-body).
-- If not chunked, then this will create the entire entity-body so as to be available
-- 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_execution_variable)'
-- We ignore the results of content negotiation, as there is only one possible combination.
do
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 order_to_json (l_order) as jv then
req.set_execution_variable (Generated_content_execution_variable, jv.representation)
else
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_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_execution_variable) as l_response then
-- postcondition generated_content_set_for_get_head of `ensure_content_available'
Result := l_response
end
end
next_chunk (req: WSF_REQUEST): TUPLE [a_chunk: READABLE_STRING_8; a_extension: detachable READABLE_STRING_8]
-- Next chunk of entity body in response to `req';
-- The second field of the result is an optional chunk extension.
do
-- precondition `is_chunking' is never met, but we need a dummy `Result'
-- to satisfy the compiler in void-safe mode
Result := ["", Void]
end
generate_next_chunk (req: WSF_REQUEST)
-- Prepare next chunk (including optional chunk extension) of entity body in response to `req'.
-- This is not called for the first chunk.
do
-- precondition `is_chunking' is never met
end
feature -- DELETE
delete (req: WSF_REQUEST)
-- Delete resource named in `req' or set an error on `req.error_handler'.
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)
else
req.error_handler.add_custom_error ({HTTP_STATUS_CODE}.method_not_allowed, "DELETE not valid",
"There is conflict while trying to delete the order, the order could not be deleted in the current state")
end
else
req.error_handler.add_custom_error ({HTTP_STATUS_CODE}.not_found, "DELETE not valid",
"There is no such order to delete")
end
end
delete_queued (req: WSF_REQUEST): BOOLEAN
-- Has resource named by `req' been queued for deletion?
do
-- No
end
feature -- PUT/POST
is_entity_too_large (req: WSF_REQUEST): BOOLEAN
-- 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_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
create_resource (req: WSF_REQUEST; res: WSF_RESPONSE)
-- Create new resource in response to a PUT request when `check_resource_exists' returns `False'.
-- Implementor must set error code of 200 OK or 500 Server Error.
do
-- We don't support creating a new resource with PUT. But this can't happen
-- with our router mappings, so we don't bother to set a 500 response.
end
append_resource (req: WSF_REQUEST; res: WSF_RESPONSE)
-- 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_execution_variable) as l_order then
submit_order (l_order)
compute_response_post (req, res, l_order)
else
handle_bad_request_response ("Not a valid order", req, res)
end
end
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_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_execution_variable) as l_order then
if not is_valid_to_update (l_order) then
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_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
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 (Conflict_check_code_execution_variable)'.
-- 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_execution_variable) as l_request then
l_order := order_from_request_input_data (l_request)
if req.is_put_request_method then
l_id := order_id_from_request (req)
if l_order /= Void and then l_id /= Void and then has_order (l_id) then
l_order.set_id (l_id)
req.set_execution_variable (Request_check_code_execution_variable, {NATURAL} 0)
req.set_execution_variable (Extracted_order_execution_variable, l_order)
else
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_execution_variable, {NATURAL} 0)
req.set_execution_variable (Extracted_order_execution_variable, l_order)
end
else
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
update_resource (req: WSF_REQUEST; res: WSF_RESPONSE)
-- 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_execution_variable) as l_order then
update_order (l_order)
compute_response_put (req, res, l_order)
else
handle_internal_server_error (res)
end
end
feature -- HTTP Methods
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
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
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 {NONE} -- Implementation Repository Layer
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
-- update_order (an_order: ORDER)
-- -- update the order to the repository
-- do
-- an_order.add_revision
-- db_access.orders.force (an_order, an_order.id)
-- end
-- delete_order (an_order: STRING)
-- -- update the order to the repository
-- do
-- db_access.orders.remove (an_order)
-- end
feature -- Helpers
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
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_VALUE
do
Result := order_serialization.to_json (obj)
end
order_from_json (jv: JSON_VALUE): detachable ORDER
do
if attached {ORDER} order_serialization.from_json (jv, {ORDER}) as o then
Result := o
end
end
order_serialization: JSON_SERIALIZATION
do
create Result
Result.register (create {ORDER_JSON_SERIALIZATION}, {ORDER})
end
note
copyright: "2011-2017, Javier Velilla and others"
license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
end