Version 6.3.8 for OpenVMS
 —  Natural Web I/O Interface  —

Introduction

This document describes the purpose and the functions of the Natural Web I/O Interface.

Note:
This introduction mainly describes how the Natural Web I/O Interface works in a runtime (production) environment. The section Differences in a SPoD Development Environment briefly explains the special version that is used in a SPoD development environment.


What is the Natural Web I/O Interface?

The Natural Web I/O Interface is used to execute Natural applications in a web browser. It fully supports the following:

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Components of the Natural Web I/O Interface

The Natural Web I/O Interface consists of a server and a client.

Server

The Natural Web I/O Interface server enables you to use a browser as the I/O device for Natural applications. The server does the user authentication, creates the Natural session and handles the I/O between Natural and the client. The Natural Web I/O Interface server is installed on the same machine as the Natural application.

Client

The client handles the communication between the user's web browser and the Natural Web I/O Interface server. It converts the output from the Natural application to web pages, and returns the user input to Natural.

Two types of client are supported:

The client is installed on a web/application server. This can be done on any machine in the network.

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Executing a Natural Application in a Web Browser

The Natural Web I/O Interface receives data from a Natural application and delivers web pages to the user's web browser. This is illustrated in the following graphic:

Communication between browser and Natural

The communication steps for executing a Natural application in the web browser are:

  1. The user enters the address (URL) of a logon page in the web browser. The client then displays the logon page in the web browser.

    Note:
    For information on how to invoke and configure the logon page, see Configuring the Client.

  2. The user enters all required information for starting a Natural application into the logon page. This information is sent to the client.

  3. The client asks the Natural Web I/O Interface server to start the requested Natural application for this user.

  4. The Natural Web I/O Interface server checks the supplied user ID and password, creates a Natural session for the user and starts the Natural application.

  5. The Natural application returns the first application screen which is then transferred via the Natural Web I/O Interface server to the client and finally as a web page to the web browser.

Different web browsers are supported. Note that cookies and JavaScript must be enabled in the web browser. For a list of the currently supported web browsers, see the documentation for the type of client that you are using:

With Firefox, you can use caret browsing. The following exception applies for Natural applications: you can only use the RIGHT-ARROW and LEFT-ARROW keys to position the cursor (also called "caret") in an output field. Caret browsing is enabled and disabled by pressing F7. For more information, see the documentation for your web browser.

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Client-Server Compatibility

The following rules apply:

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Terminology

On the different Natural platforms for which the Natural Web I/O Interface is supported, different techiques are used for implementing the server part of the Natural Web I/O Interface. On Natural for UNIX and Natural for OpenVMS, it is implemented as a daemon. On Natural for Windows, it is implemented as a service. On the mainframe, it is implemented as a server. In this documentation, the general term "server" is therefore used for all different kinds of implementation.

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Differences in a SPoD Development Environment

The previous sections of this introduction have described how the Natural Web I/O Interface works in a runtime (production) environment. This section briefly explains the differences in a SPoD development environment.

A special version of the Natural Web I/O Interface is used when working in a remote development environment with Natural for Windows (SPoD). In this case, the Natural Web I/O Interface is an integrated component which does not require a separate installation. The server is part of the Natural Development Server (NDV), and the client is part of Natural Studio. Other than in the runtime environment, the screen is not displayed in a browser but in a normal window. Rich GUI pages created by Natural for Ajax are not supported in the development environment.

It is important that I/O via the Natural Web I/O Interface has been enabled on the Natural host. Otherwise, the Natural Web I/O Interface cannot be invoked. See also Unicode Input/Output Handling in Natural Applications in the Unicode and Code Page Support documentation.

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Restrictions When Using the Natural Web I/O Interface with Natural Applications

There are several restrictions when using the Natural Web I/O Interface with Natural applications on UNIX, OpenVMS, mainframe or Windows hosts.

Note:
The term "application" refers to application software. It does not refer to system software or software for development.

The following restrictions apply:

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Differences between the Natural Web I/O Interface Client and Terminal Emulation

The Natural Web I/O Interface client runs as an HTML terminal emulator inside a browser control. The look and feel of the Natural Web I/O Interface client display is quite similar to that of the regular terminal (emulation), but there are some differences due to browser functionality:

IBM Mainframes Only

VT Only

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