EWF/examples/restbucksCRUD

Restbuck Eiffel Implementation based on the book of REST in Practice

This is an ihmplementation of CRUD pattern for manipulate resources, this is the first step to use the HTTP protocol as an application protocol instead of a transport protocol.

Restbuck Protocol

Verb	URI or template	Use
POST	/order	Create a new order, and upon success, receive a Locationheader specifying the new order's URI.
GET	/order/{orderId}	Request the current state of the order specified by the URI.
PUT	/order/{orderId}	Update an order at the given URI with new information, providing the full representation.
DELETE	/order/{orderId}	Logically remove the order identified by the given URI.

Resource Represenation

The previous tables shows a contrat, the URI or URI template, allows us to indentify resources, now we will chose a representacion, for this particular case we will use JSON.

Note:

1. A resource can have multiple URIs.
   
2. A resource can have multiple Representations.
   

RESTBUCKS_SERVER

This class implement the main entry of our REST CRUD service, we are using a default connector (Nino Connector, using a WebServer written in Eiffel). We are inheriting from URI_TEMPLATE_ROUTED_SERVICE, this allows us to map our service contrat, as is shown in the previous table, the mapping is defined in the feature setup_router, this also show that the class ORDER_HANDLER will be encharge of to handle different type of request to the ORDER resource.

class
	RESTBUCKS_SERVER

inherit
	ANY

	URI_TEMPLATE_ROUTED_SERVICE

	DEFAULT_SERVICE
		-- Here we are using a default connector using the default Nino Connector,
		-- but it's possible to use other connector (CGI or FCGI).

create
	make

feature {NONE} -- Initialization

	make
		-- Initialize the router (this will have the request handler and 
		-- their context).
		do
			initialize_router
			make_and_launch
		end

	create_router
		do
			create router.make (2)
		end

	setup_router
		local
			order_handler: ORDER_HANDLER [REQUEST_URI_TEMPLATE_HANDLER_CONTEXT]
		do
			create order_handler
			router.map_with_request_methods ("/order", order_handler, <<"POST">>)
			router.map_with_request_methods ("/order/{orderid}", order_handler, <<"GET", "DELETE", "PUT">>)
		end

feature -- Execution

	execute_default (req: WSF_REQUEST; res: WSF_RESPONSE)
			-- I'm using this method to handle the method not allowed response
			-- in the case that the given uri does not have a corresponding http method
			-- to handle it.
		local
			h : HTTP_HEADER
			l_description : STRING
			l_api_doc : STRING
		do
			if req.content_length_value > 0 then
				req.input.read_string (req.content_length_value.as_integer_32)
			end
			create h.make
			h.put_status ({HTTP_STATUS_CODE}.method_not_allowed)
			h.put_content_type_text_plain
			l_api_doc := "%NPlease check the API%NURI:/order METHOD: POST%NURI:/order/{orderid} METHOD: GET, PUT, DELETE%N"
			l_description := req.request_method + req.request_uri + " is not allowed" + "%N" + l_api_doc
			h.put_content_length (l_description.count)
			h.put_current_date
			res.set_status_code ({HTTP_STATUS_CODE}.method_not_allowed)
			res.write_header_text (h.string)
			res.write_string (l_description)
		end

end

How to Create an order

* Uri: http://localhost:8080/order
* Method: POST
* Note: you will get in the response the "location" of the new your order.
* HEADERS:

  Content-Type: application/json

* Example CONTENT
     
      {
	"location":"takeAway",
	"items":[
	        {
	        "name":"Late",
	        "option":"skim",
	        "size":"Small",
	        "quantity":1
	        }
	    ]
	}

How to Read an order

* Uri: http://localhost:8080/order/{order_id}
* Method: GET

How to Update an order

* Uri: http://localhost:8080/order/{order_id}
* Method: PUT

How to Delete an order

* Uri: http://localhost:8080/order/{order_id}
* Method: DELETE

References

1. How to get a cup of coffe
2. [Rest in Practice] (http://restinpractice.com/default.aspx)