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Client Workflow Overview
vFabric Data Director API clients implement a RESTful workflow, making HTTP requests to the server and
retrieving the information they need from the server’s responses.
About RESTful Workflows
REST, an acronym for Representational State Transfer, describes a programming style that relies on inherent
properties of hypermedia to create and modify the state of an object. The object's serialized representation is
accessible as a URL.
If a URL of such an object is known to a client, the client can use an HTTP GET request to retrieve the
representation of the object. In the Data Director API, this representation is an XML document or a JSON
object.
In a RESTful workflow, representations of object state are passed back and forth between a client and a
service with the explicit assumption that both parties have only the information about an object that is
presented in a single request or response. The URLs at which these documents are available often persist
beyond the lifetime of the request or response that includes them.
Data Director REST API Workflows
Application programs written to a REST API use HTTP requests that are often executed by a script or other
higher-level language to make remote procedure calls. These calls create, retrieve, update, or delete objects
that the API defines. In the Data Director API, these objects are defined by a collection of XML schemas. The
operations themselves are HTTP requests, and are generic to all HTTP clients.
To write a RESTful client, you must understand the HTTP protocol and the semantics of either XML or
JSON. You also need an HTTP client, such as Wget. To use the Data Director API effectively with your client
code, you can first learn about Data Director by reviewing the vFabric Data Director Administrator and User
Guide. You can then learn about the Data Director XML schemas, which are documented for both XML and
JSON formats in VMware vFabric Data Director Call Reference . Learn how to answer questions like the
following.
n
What objects does the API support and what do the objects represent. For example, what is a database
group and how does it relate to an organization?
n
How does the API represent these objects. For example, what does the request or response body for an
Org object look like? What do the Org object's elements and attributes represent?
n
How does the client refer to an object on which it wants to operate. For example, where are the links to
objects in a database group? How does a client obtain and use them?
Your client code can read an object by making an HTTP GET request to the object’s URL. Your client code
can create or modify an object with an HTTP POST or PUT request that includes a new or changed XML or
JSON body for the object, and delete an object with an HTTP DELETE request.
RESTful Workflow Patterns
All RESTful workflows follow a common pattern.
1 Make an HTTP request, typically GET, PUT, POST, or DELETE. The target of this request is the path to
the Data Director API, or a URL obtained from the response to a previous request. For example, a GET
request to an organization URL returns Data Director objects that the organization contains.
Chapter 1 Data Director API Overview
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