Chapter 6. Component Overview

formVista(tm) uses a model for web application development that divides a webpage into "components”. A formVista(tm) component is a combination of technologies including HTML, Javascript, PHP and SQL among others that when combined delivers a piece of completed functionality to the user, possibly across multiple pages.

In many ways, formVista component are similar to Flash movies or Java Applets with the distinction that they are used on the server side and appear as an integral part of the page.

formVista(tm) components are built using an XML dialect called the formVista Markup Language or FVML for short. This language describes:

1. the structure of the component

2. how the component should interact with any data sources (sql databases, the filesystem, etc)

3. how the component should interact with the user

4. error checking

5. validation rules

6. business logic

7. client side Javascript and AJAX functionality

The appearance of the component on the webpage is dictated by a “theme” or “skin” which is created in an external set of template files.

Once created, components are loaded and invoked on a webpage by a simple set of PHP calls. The interface to the webpage, called simpleVista, has been optimized to be as simple as possible to allow non-programmers to field these components in much the way non-programmers can field flash movies or java applets.

For example, consider a signup form. In a normal web application there are many separate pieces that need to be kept track of including:

• a script to maybe load some data into the signup form.

• the signup form itself.

• the javascript to do some client side validation.

• a script to process the form variables.

• some SQL to add the signup to the database

• an email processor to send a thank you confirmation email.

• an email processor to send a note to an admin.

• some more HTML to say thank you to the user through the browser.

• some more code to handle the confirmation click through

• yet some more HTML to say thank you for the confirmation.

An example of such a form is the forum registration form.

Because there are all these pieces spread across multiple pages and they are all inextricably tied to the surrounding webpages, reusing this form in any other project involves alot of work.

Combine all of these parts into one thing in one file that can be placed onto any page and you would have a single formVista component. What separates formVista from other frameworks is this view of components that involves so many seemingly disparate parts and may span many pages and many requests. The framework does all the magic behind to dynamically bring in and hook up anything the component needs to run behind the scenes.

Once built, the individual placing the component needs to know nothing about how the component works. Additionally, the web-designer has a large degree of freedom to theme the component to match the look of any site without needing any programming experience and without affecting the functionality. The themes thus created are also reuseable on any other similar components.

Some examples of components are:

• a ticket list and bug tracker

• a categorized articles list

• a contact us form

• a cascading menu system

• the formVista forum.