GetMetaData

Description

Gets metadata (such as the methods, properties, and parameters of a component) associated with an object that is deployed on the ColdFusion server.

Returns

Structured metadata information: for ColdFusion components (CFCs) and user defined functions (UDFs), a structure; for query objects, an array of structures.

Function syntax

GetMetaData(object)

History

ColdFusion MX 7: Added support for getting query object metadata.

ColdFusion MX: Added this function.

Parameters

Parameter	Description
object	A ColdFusion component, user-defined function, or query object. Within a CFC, the parameter can also specify the This scope.

Usage

This function provides information about application data, and lets applications dynamically determine the structure of an object and how to use it. This function is useful for CFCs and query objects. The metadata for a CFC includes information on the component and its functions, arguments, and properties. The getMetaData function also returns metadata for user-defined functions that not part of CFCs.

The following table lists the data returned by the function for supported object types:

Object	Field	Description
Component		A structure containing the following fields:
	displayname	Value of the `cfcomponent` tag `displayname` attribute, if any.
	extends	Metadata for the component's ancestor component. Components that do not explicitly extend another component extend the WEB-INF.cftags.component.
	functions	Array of metadata structures for the component's functions.
	hint	Value of the `cfcomponent` tag `displayname` attribute, if any.
	name	Component name, including the period-delimited path from a component search root such as the web root or a directory specified in the administrator Custom Tag Paths page.
	output	Value of the `cfcomponent` tag `output` attribute, if any
	path	Absolute path to the component.
	properties	Array of structures containing metadata specified by the component's `cfproperty` tags, if any.
	type	Always, component.
	userMetadata	User-specified attributes in the `cfcomponent` tag
Function		A structure containing the following fields.
	access	Value of the `cffunction` tag `access` attribute, if any.
	displayname	Value of the `cffunction` tag `displayname` attribute, if any.
	hint	Value of the `cffunction` tag `hint` attribute, if any.
	name	Function name.
	output	Value of the `cffunction` tag `output` attribute, if any.
	parameters	Array of structures containing metadata for the function parameters.
	returntype	Value of the `cffunction` tag `returntype` attribute, if any.
	roles	Value of the `cffunction` tag `output` attribute, if any.
	userMetadata	User-specified attributes in the `cffunction` tag.
Parameter or Property		A structure containing the following fields:
	default	Value of the `cfargument` or `cfproperty` tag `default` attribute, if any.
	displayname	Value of the `cfargument` or `cfproperty` tag `displayname` attribute, if any.
	hint	Value of the `cfargument` or `cfproperty` tag `hint` attribute, if any.
	name	Function parameter or CFC propery name.
	required	Value of the `cfargument` or `cfproperty` tag `required` attribute, if any.
	type	Value of the `cfargument` or `cfproperty` tag `type` attribute, if any.
	userMetadata	User-specified attributes in the `argument` tag.
Query		An array of structures containing the following elements:
	IsCaseSensitive	Boolean value indicating whether character data must be case correct.
	Name	The column name.
	TypeName	The SQL data type (Omitted if the query object is created with QueryNew without specifying types.)

Note: Use the This scope to access component metadata inside the CFC. The This scope is available at runtime in the component body and in the CFC methods. It is used to read and write variables that are present during the life of the component.

For more information, see Using introspection to get information about components in Building and Using ColdFusion Components in ColdFusion MX Developer's Guide.

Example

The following example uses the cfdump tag to display metadata for the utilities CFC that is used by the ColdFusion component browser. It also displays the names and data types of the fields in the cfdocexamples database Employees table.

<!--- Create an instance of the Component Explorer utilities CFC. 
      and get its metadata --->
<cfscript>
componentutils = createObject("component", "cfide.componentutils.utils");
utilmetadata = getMetaData(componentutils);
</cfscript>

<h4>Metadata for the CFC component utilities</h4>
<cfdump var="#utilmetadata#">

<!--- use GetMetadata to get the names and data types of the fields in the 
      cfdocexamples Employees table --->
<cfquery name="getemployees" datasource="cfdocexamples">
SELECT      *
FROM         Employees
</cfquery>
<cfset employeemeta=getMetaData(getemployees)>

<h4>The Employees table has the following columns</h4>
<cfloop index="i" from="1" to="#arrayLen(employeemeta)#">
   <cfoutput>
      #employeemeta[i].name# #employeemeta[i].TypeName# #employeemeta[i].isCaseSensitive#<br>
   </cfoutput>
</cfloop>

View comments in LiveDocs