SharePoint 2007: The Definitive Guide

InfoPath Forms Architecture

Let's take a quick look at the main components of the InfoPath form and the InfoPath Forms Services architecture. The objective of this section is to provide an overall understanding of how the different components work.

An InfoPath form template (.xsn) file is actually a CAB file containing different components files. The following are some of the files contained inside the .xsn:

.xsf

A manifest file that provides the basic definition of other form files

.xsl

Defines the transformation for data into different views

.xsd

Defines the data source schema

.dll

Carries the custom logic built into .NET or COM

.htm and other resource files

Custom HTML resource files and other resources for the form

When a form template is uploaded using administrative deployment (discussed later in this chapter), the template is stored in the content database of the site. Office Forms Services provide a server-side runtime environment for InfoPath Forms Services. While running on the browser, all rules, validation, and calculations are executed in the browser using a client-side script. All business logic is executed in the server. So, when the browser requests business logic execution, a postback is executed using low-cost XMLHTTP. FormsServer.aspx is an InfoPath Forms Services page that accesses the form's data from the content database and renders it to the client. Internally, InfoPath Forms Services consists of four components that are responsible for rendering this .xsn file on the ...