Code On Time: RESTful

Monday, May 2, 2022Print Subscribe

RESTful API Engine responses are provided with the ETag header. Browsers automatically submit ETag with the subsequent requests to fetch the same resource. The engine responds with the HTTP status 304 and empty body if the ETag of the resource has not changed. Apps can also submit ETag with CRUD requests for conflict detection.

Detect the data editing conflicts and build high performance applications by taking advantage of the HTTP protocol.

The *ETag* of the resource specified in the *If-Match* header of the PATCH request allows detecting the data editing conflicts.

The items of the *Supplier Company Name* and *CategoryName* lookups are fetched from the RESTful Application with GET requests. The physical data transfer happens one time only for each lookup for each subsequent opening of the *Edit Product* form.

Firefox Developer Tools provide a complete list of HTTP requests executed by the web application. Other browsers may not provide the full picture of the network traffic between the client and the server. — The RESTful Application responds to the lookup requests with the HTTP status code 304. It tells the client that the *ETag* of the corresponding resource is unchanged and the previously fetched copy of the response can be used instead.

This tutorial is part of the RESTful Workshop designed to empower individual developers and teams to create amazing enterprise-quality backends for mobile and web applications. Zero experience and no code is required to provide your data with the REST API conforming to the Level 3 of Richardson Maturity Model with the built-in OAuth 2.0 and Open ID Connect.

Labels: Caching, Conflict Detection, RESTful

Thursday, April 21, 2022Print Subscribe

Lesson: BLOBs with RESTful API

Values of Binary Large Objects (BLOBs) are represented as resource URLs in the data. User identity must be specified in the Authorization header to get or change a BLOB. Hypermedia links to replace or delete BLOB values are included. Developers submit binary data as fields in the body property of the $app.restful method argument or as the named values in the multipart/form-data of HTTP requests.

Work with the BLOB resources like a pro.

RESTful API Engine identifies the user automatically when the host application is making a request. The cookie with the self-encrypted user access token provides the identity information.

Postman shows the BLOB fetched from the resource with the authorization key specified in the "x-api-key" query parameter. RESTful API Engine requires an access token or authorization key to be specified explicitly by the external applications.

The standalone single page application fetches the image of the product category on-demand when the category name is clicked. The app follows the hypermedia links to find the product category "picture" field value.

Labels: BLOB, REST, RESTful, RESTful Workshop

Saturday, March 19, 2022Print Subscribe

Lesson: Custom Actions With Hypermedia

The REST API Level 2 and above must support HTTP methods (verbs) in resource handling. For example, the request with the GET method is expected to return the resource data while the request with the PATCH method is expected to modify some of its fields. The number of HTTP verbs is limited and will not cover all possible scenarios of data manipulation.

Enhance the RESTful API of applications with custom actions to go beyond CRUD.

Confirmation controller "SellPrompt" presents the user with an option to sell 1, 5, or 10 units of a product with a single touch. The "Other" option allows entering the arbitrary quantity of units to sell. The prompt is displayed when users press the "Sell" button in the product form.

RESTful API Engine makes the custom action "sell" available to the client apps. The parameters of the action are specified in the "parameters" key of the payload. The new state of the resource is returned in the response.

Labels: Business Rules, Custom Actions, Reports, REST, RESTful, RESTful Workshop

RESTful

Learn how to make your apps faster with ETag and Caching. Use the ETag header to detect conflicts.