ColdFusion 9.0 Resources

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 are not part of CFCs. Use the GetComponentMetaData function to get information about ColdFusion interfaces, or about CFC definitions that you have not instantiated.

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.
	`fullname`	The dot delimited path from the cf_webroot of the component.
	`functions`	Array of metadata structures for the component’s functions.
	`hint`	Value of the `cfcomponent` tag `displayname` attribute, if any.
	`implements`	A structure containing the metadata of the interfaces that the component implements. The key of the structure is the interface name, and the value is a structure containing the interface metadata.
	`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.
	`returnformat`	The format in which to return values to a remote caller. This attribute has no effect on values returned to a local caller.
	`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 property 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 the Developing ColdFusion Applications.

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>