Webulator/400 Architecture


Webulator/400 Overview

Webulator/400 version 2.0 is packaged offering that incorporates a highly specialized HTTP server and CGI program that allows users to run AS/400 green screen applications inside their browser.

The Webulator/400 server will only fulfill Webulator/400 session requests and will not fulfill any other standard HTTP requests such as images and HTML files. Webulator/400 is meant to be used in conjunction with other native AS/400 servers such as I/NET's Web Server/400 and Commerce Server/400 or IBM's ICS and ICSS servers.

The Webulator/400 server interacts with OS/400 through a set of APIs known as the Virtual Terminal (VT) APIs. The VT APIs allow Webulator/400 to emulate a physical device that is connected to an AS/400. They allow Webulator/400 to open, read, write and close virtual devices.

A typical session would consists of a user accessing a Webulator/400 session. The server would read the session configuration, open the device and wait for screen data to be made available for that session. Once screen data was available, the server would convert the 5250 data stream to a HTML form and return it to the browser. At that time, the HTTP protocol would drop the connection. After the user has completed the necessary input fields on the Webulator/400 screen, they would press a desired action key and the form would be returned back to the Webulator/400 server. At that time the server would write the returned data to the AS/400 and wait for additional screen data to be made available. This sequence of events would continue until the session was terminated either through an user action or a timeout value and the server would close the corresponding virtual device making it available for another user.

Changes from Version 1.x

Users of previous versions of Webulator/400 will notice a rather large design change in version 2.0. Version 1.x was an add on product to I/NET's Web Server/400 and Commerce Server/400 servers. Version 2.0 incorporates key Commerce Server/400 components with an enhanced version of the Webulator/400 1.1 into a single product that allows it to run with any native AS/400 Web server.

The packaging of portions of Commerce Server/400 and Webulator/400 into one package should not be misconstrued to mean that Webulator/400 version 2.0 is a stand alone package. While it may be possible to run version 2.0 as a standalone package, you will not be able to take advantage of all of Webulator/400's features if you do not have a native AS/400 Web server running. The Webulator/400 server has all of the functionality needed to properly handle input from a user, but it may generate HTML forms that have other objects embedded into them that require a HTTP server to deliver. For example, the keyboard plugin and any embedded images will not work correctly unless a full featured HTTP server is also available.

Version 2.0 also uses different TCP/IP ports than previous versions. Since previous versions of Webulator/400 were essentially a CGI script being called from Web Server/400 or Commerce Server/400, it run on the same port as the server. Because version 2.0 has its own embedded server, it must run either on a non standard port on your existing TCP/IP address or run a separate TCP/IP address. Webulator/400's new default port is 5061.