Using introspection to get information about components



ColdFusion provides several ways for you to get information about components:

  • Request a component page from the browser

  • Use the ColdFusion component browser

  • Use the Adobe® Dreamweaver® Components panel

  • Use the GetMetaData function

Development teams can use the information about components as up-to-date API reference information.

Note: For information about how to include documentation in CFCs for display by using introspection, see Documenting CFCs.

Requesting a component page from the browser

When you access a CFC directly with a web browser without specifying a component method, the following chain of events occurs:

  1. The request is redirected to the cfcexplorer.cfc file, which is located in the cf_root/wwwroot/CFIDE/componentutils directory.

  2. The cfcexplorer component prompts users for the ColdFusion RDS or Administrator password, if necessary.

  3. The cfcexplorer component renders an HTML description and returns it to the browser.

Using the ColdFusion component browser

You can also browse the components available in ColdFusion using the component browser, which is located at cf_root/wwwroot/CFIDE/componentutils/componentdoc.cfm.

The browser has three panes:

  • The upper-left pane lists all CFC packages that ColdFusion can access, and has all components and refresh links.

  • The lower-left pane lists CFC component names. When the browser first appears, or when you click the all components link in the upper pane, the lower pane lists all available components. If you click a package name in the upper left pane, the lower pane lists only the components in the package.

  • The right pane initially lists the paths of all components. When you click a component name in the lower-left pane, the right pane shows the ColdFusion introspection page, as described in Requesting a component page from the browser.

Note: When RDS user names are enabled, the component browser accepts the root administrator user (admin) with either the administrator or RDS single password.

Using the Dreamweaver Components panel

The Dreamweaver Components panel lists all available components, including their methods, method parameters, and properties. The panel’s context menu includes options to create a component, edit the selected component, insert code to invoke the component, or show detailed information on the component or component element. The Get description option shows the ColdFusion introspection page, as described in Requesting a component page from the browser. For more information on viewing and editing CFCs in Dreamweaver, see the Dreamweaver online Help.

Using the GetMetaData function

The CFML GetMetaData function returns a structure that contains all the metadata of a CFC instance. This structure contains substantially more data about the CFC than the cfdump tag shows, and includes the following information:

  • All attributes to the component tag, including any metadata-only attributes, plus the component path.

  • An array of structures that contains complete information on each method (function) in the component. This information describes all attributes, including metadata-only function and parameter attributes.

  • Within each function structure, a Parameters element that contains an array of parameters specified by cfargument tags. Information on each parameter includes any metadata-only attributes.

  • Information about any properties that are specified using the cfproperty tag.

Display metadata for a CFC

  1. Create the tellAboutCfcs.cfm file in the same directory as the telltime.cfc file, with the following code:

    <!--- Create an instance of the component. ---> 
<cfobject component="tellTime" name="tellTimeObj"> 
<!--- Create a structure. ---> 
<cfset aboutcfc=structNew()> 
<!--- Populate the structure with the metadata for the 
            tellTimeObj instance of the tellTime CFC. ---> 
<cfset aboutcfc=GetMetaData(tellTimeObj)> 
<cfdump var="aboutcfc">

  2. View the tellAboutCfcs.cfm file in a browser.

For information on how to specify CFC metadata, including how to use component tags and how to specify metadata-only attributes, see Documenting CFCs.