Mapping an Application Framework

An important step in designing a ColdFusion application is mapping its directory structure.

Before you start building the application, establish a root directory for the application. You can store application pages in subdirectories of the root directory.

Processing Application.cfm and OnRequestEnd.cfm

ColdFusion uses similar but different rules to locate and process Application.cfm and OnRequestEnd.

Processing Application.cfm

When any ColdFusion application page is requested, ColdFusion searches up the page's directory tree for an Application.cfm file. When it is found, the Application.cfm code is logically included at the beginning of that page.

If it is not found, ColdFusion searches up the directory tree until it finds an Application.cfm file. If more than one Application.cfm file is in the current directory tree, ColdFusion uses the first one it finds.

Only one Application.cfm file is ever processed for each ColdFusion application page. The Application.cfm file is automatically included in each application page, as if by a cfincludetag. If the Application.cfm page it is present in the directory tree, there is no way not to include it. For this reason, it is the ideal location to set application-level variables.

If an application page has a cfinclude tag pointing to an additional application page, ColdFusion does not initiate another search for an Application.cfm page when it includes the additional page.

If your application runs on a UNIX platform, which is case sensitive, you must spell Application.cfm with an initial capital letter.

Processing OnRequestEnd.cfm

Just as the Application.cfm file is executed before each application page it governs, you can specify a file named OnRequestEnd.cfm, which is executed after each application page in the same application.

ColdFusion Server looks for the OnRequestEnd.cfm file in the same directory as the Application.cfm file of the current application page. The OnRequestEnd.cfm file is never executed if it resides in another directory.

The OnRequestEnd.cfm file is not executed if there is an error or an exception in the called page, or if the called page executes the cfabortor cfexit tag.

Just as the Application.cfm file must be spelled with a capital A on UNIX systems, you must spell the OnRequestEnd.cfm file with capital O, R, and E.

Defining the directory structure

Defining a root directory for an application has a number of advantages:

Development The application is easier to develop and maintain because the application page files are well organized.
Portability You can more easily move the application to another server or another part of a server without changing any code in the application page files.
Application-level settings Application pages that fall under the same root directory can share application-level settings and functions.
Security Application pages that fall under the same directory can share Web server security settings.

You can use a single Application.cfm file for your application, or use different Application.cfm files that govern individual sections of the application.

The following directory trees illustrate two approaches to implementing the Application Framework:

In the first example, a company named Web Wonders, Inc. uses a single Application.cfm file installed in their application root directory to process all application page requests.
The example on the right shows how Bandwidth Associates uses the settings in individual Application.cfm files to specify processing for ColdFusion applications at the departmental level. Only the Products application pages are processed using the settings in the root Application.cfm file. The Consulting, Marketing, and Sales directories have their own Application.cfm file.

Developing ColdFusion Applications
Using the Application Framework