The Oracle Database Appliance Browser User Interface (BUI) is a web-based application to administer and manage the appliance. The BUI uses Oracle Javascript Extension Toolkit (JET) framework (http://oraclejet.org) which supports the Model-View-ViewModel (MVVM) architectural design pattern.
The Oracle JET framework provides a set of UI components with built-in accessibility support. To support the MVVM design, Oracle JET is built upon a modular framework that includes a collection of third-party libraries and Oracle-provided files, scripts, and libraries.
DCS Controller: When you access the BUI URL, the browser sends an HTTP request to the DCS controller, to send a copy of the web application. The request consists of a line indicating a method such as GET or POST, a Uniform Resource Identifier (URI) indicating which resource is being requested, and an HTTP protocol version.
The index.html page is the first page to download and becomes the blueprint by which the web application is constructed. As the browser reads the HTML code, it sends out more requests to the DCS controller to send more pieces of the page. The browser caches static assets, that is, the parts of a website that do not change from visit to visit, such as images, HTML, CSS, and JavaScript. Once the request is processed successfully, the login page is rendered on the browser.
The BUI code that runs on the client side makes a REST API call to the DCS agent for all requests and processes the results that are sent back. The DCS agent is managed outside of the DCS controller and runs on a separate web server. Each request to the DCS agent is made as an asynchronous call. The DCS agent generates a response based on the REST API call and includes the HTTP protocol version and the HTTP status code. The agent sends back a response to the browser for the request made. The client-side code then processes the result sent back by the DCS agent and presents it on the BUI. The status code and reason phrase tell the client how the server handled the request.
Generally, the status code 200 is returned, indicating that the request was handled successfully and the body data contains the requested item. Other result codes indicate HTTP errors, such as 404 Not Found.