APL2000 APL+WebComponent Overview

APL+WebComponent is APL running in the IE browser. The IE browser supports Jscript which is the name Microsoft has given to their version of JavaScript. Jscript/JavaScript is ubiquitous in web browsers, and the only programming language available in all browsers.

While APL+WebComponent provides a simple and straight forward method for publishing your application to the web, there is a rather significant learning curve when creating and deploying your first application.

This learning process includes gaining an understanding of client/server layout, the differences in security models for the Browser environment vs. standalone windows applications, and other related issues.

If your first application has a short timeline or is reasonably complex, we would strongly suggest that you consider either Lescasse Consulting or APL2000 Consulting to assist in your first effort. It will definitely reduce the learning curve you will experience.

This version of APL+WebComponent is specifically designed for the Microsoft IE browser, as over 95% of all browsers are Microsoft IE browsers, according to the latest statistics published by OneStat.com, WebSideStory, IDC and Media/Metrirx. Netscape/Mozilla browsers make up less than 2%, and Opera has 0.9%.

This means that APL+WebComponent runs on more machines than any other APL ever developed.

The primary use envisioned for APL+WebComponent is to publish the user interface of an APL application.

APL+WebComponent utilizes Web Services to interface to the server from the browser. All data is sent to the server in a SOAP envelope over HTTP and the result from the server is sent back to the browser in a SOAP envelope over HTTP. The connection is synchronous making it possible to execute a function on the server with the results being placed in a variable on a line of code in a function on the client.

Tests using the Microsoft Application Test Center show that APL+WebServer supports over 250 transactions per second on a 1 gig standard desktop.

There is no requirement that the server side be a Microsoft OS. The server side can also be Linux or Unix, with APL2000 running on the server.

The APL+WebServer has been designed for the Microsoft NT, 2000, 2003 and XP operating systems. However, the same Web Services support can be created on the Linux and Unix platforms using APL2000 and the HTTP server workspaces available for those platforms.

APL+WebComponent is designed to integrate with existing APL2000 applications and publish the user interface to the browser. The JsaveSDK provides the ability to publish interface related functions to the browser. These functions can be published as a .js file or .htm file. Typically utility type functions, used by several applications would be published in a .js file and the application functions would go in the .htm file. The .htm file can reference the .js files.

The primary change to an APL application is to add a function named RunAtServer which takes a right argument of the format

yourFunctionName arg1 arg2 arg3 etc.

and returns the result of the right arguments with no action inside the function. This does not affect the existing stand alone application, however, when the application is ported to APL+WebComponent the right argument of RunAtServer is executed on the server, and the result is placed in a variable on the client.

The change to a typical function would look something like this:

[21] res„RunAtServer foo arg1 arg2 arg3

[22] ....

where the function RunAtServer looks something like this:

[0] data„RunAtServer data

Things that would normally run on the server would be functions that access databases, native files, share files, complex APL calculations, wcall’s, assembler routines, etc.

This is particularly nice, in that proprietary functions are never published, and exist only on the server. Only the functions involved in the user interface need to be published.

There are many benefits to deploying a client/server application.

1. User has access to only interface code, not proprietary calculation engines
2. User does not have to download and install any code, “zero footprint” application
3. Application runs on 95% of all machines (IE Browser)
4. If a user can access the Yahoo web site, the user can run your application
5. Updates to the application can be done at any time by simply changing the APL+WebComponent code on the server, or by changing your server workspace on the server
6. The user starts using the update the next time they start your application
7. By integrating with APL2000, you can build a standalone application and a client/server application in one workspace. No duplicate code.
8. APL+WebComponent and APL+WebServices perform all the communications for the application, there is no need to build any communications code.
9. Sell your application in the client/server market with little additional work.

APL+WebComponent SDK makes it possible to publish your existing application simply and easily. The APL+WebComponent SDK creates a complete client application ready to be published.

In debug mode, the APL+WebComponent reports the line of APL code where a problem exists, making it simple to check for errors.

APL+WebComponent, in conjunction with the APL+WebServer, makes creating a client/server Web Services application simple and easy.