The PL/B Web Server

With the introduction of the Sunbelt PL/B Web Server, current Visual PL/B and Linux customers can provide PL/B applications directly to their end-user customers by way of an industry standard browser or a Sunbelt Web Application. The clients are industry standard products that do not require any explicit downloads, installations, or configurations before use with the PL/B Web Server. The clients' interface is based on simple URL strings that connect to the PL/B Web Server.

Like the PL/B Application Server, the PL/B Web Server provides split runtime operations for language instructions. The language instructions execute at the host server and the user interface operations are performed at the client. When the PL/B Web Server runtime encounters an instruction that requires user interface, the server dynamically generates the HTML5, JavaScript, and CSS classes that interface with the browser client. Programs execute exactly as expected although there are some limitations imposed by the environment.

The PL/B Web Server optimizes language operations using data shadowing and instruction buffering to give the best performance possible. Caching at the PL/B Web clients exist only as implemented by the browser.

As a general comment, the PL/B Web Server runtime executes a PL/B program exactly the same as any other Sunbelt PL/B runtime. However, any PL/B instructions that perform input\output operations for the User Interface have been changed to dynamically generate HTML5 and JavaScript logic that interfaces with a PL/B Web Client. A PL/B Web Client can be an industry standard browser or a Sunbelt Web App.

Therefore, most PL/B instructions\programs\object behaviors are implemented by the PL/B Web server. While the PL/B Web Server runtimes attempt to maintain the same behaviors, there may be some scenarios where a PL/B behavior may be different or unsupported. The PL/B Web Server supports a subset of the normal PL/B GUI objects.

To help maintain a high level of performance for the PL/B programs, the PL/B Web Server has implemented server side data shadowing techniques to minimize the data transfers to and from the PL/B Web Clients.