RESTful Web service apply the ideas of the web to data-delivery, by providing scalable, flexible and stateless access to data assets based on well-known protocols and formats like HTTP, HTML, XML and JSON. Additionally to traditional SQL type access methods such as JDBC or ODBC, all the views in Denodo can be accessed using the RESTful interface.
The Denodo RESTful Web service is an HTTP service deployed by default in the URL http://localhost:9090/denodo-restfulws that exposes resources like databases and views in the following standard representation formats:
- XML
- JSON
- XHTML (more user-friendly)
This Web service allows Denodo to work inside applications following the REST service architecture style and provides support for linked data in the enterprise deployment (see next section for more information about this).
When accessed from a browser, the Denodo RESTful endpoint will look like this:
See the examples below to know how to query this service:
- Example 1: http://localhost:9090/denodo-restfulws/tutorial
-> returns the list of views of the virtual database
tutorial.
- Example 2: http://localhost:9090/denodo-restfulws/tutorial/views/client
-> returns the content of the view
clientof the databasetutorial.
- Example 3: http://localhost:9090/denodo-restfulws/tutorial/views/client?client_id=C005
-> returns the content of the view
clientwhoseclient_idisC005.
Representations
We mentioned at the beginning of this section that Denodo supports three representation formats (XML, JSON and XHTML). You saw in the previous examples the XHTML format using a browser. How can you get the response in the other formats? The answer is easy, by adding a query parameter to the URL:
- JSON output: you have to add
$format=json. For example,
http://localhost:9090/denodo-restfulws/tutorial/views/client?client_id=C005&$format=json
- XML output: you have to add
$format=xml. For example,
http://localhost:9090/denodo-restfulws/tutorial/views/client?client_id=C005&$format=xml
Another way to choose the desired representation is using HTTP 'Accept' headers.
In the next section, you will learn how to link your Denodo views to allow browsing linked data through the RESTful Web service.