The vCloud API represents objects as XML documents in which object properties are encoded as elements and attributes with typed values and an explicit object hierarchy defined by an XML schema.

XML representations of first-class vCloud API objects, such as the objects in vCloud API Object Taxonomy, include these attributes.

id

The object identifier, expressed in URN format. The value of the id attribute uniquely identifies the object, persists for the life of the object, and is never reused. The id attribute value is intended to provide a context-free identifier that can be used with the vCloud API entityResolver

(see Retrieve an Object as an Entity).

type

The object type, specified as a MIME content type.

href

An object reference, expressed in URL format. Because this URL includes the object identifier portion of the id attribute value, it uniquely identifies the object, persists for the life of the object, and is never reused. The value of the href attribute is a reference to a view of the object, and can be used to access a representation of the object that is valid in a particular context. Although URLs have a well-known syntax and a well-understood interpretation, a client should treat each href as an opaque string. The rules that govern how the server constructs href strings might change in future releases.

This XML fragment, extracted from the representation of a vApp, shows its id, type, and href attributes.

<VApp
   ...
   id="urn:vcloud:vapp:490af534-1491-452e-8ed6-a5eb54447dac"
   type="application/vnd.vmware.vcloud.vApp+xml"
   href="https://vcloud.example.com/api/vApp/vapp-490af534-1491-452e-8ed6-a5eb54447dac"
   ... >
   ...
</VApp>