The Semantic Web - Social Semantics: The Search for Meaning on the Web - page 66

User Agent

HTTP 303
See Other

normation
Resource

Server

Fig. 3.5 The 303 redirection for URIs

the common-sense requirement that the URI for a thing itself on the Semantic Web
should be separate from the URI for some information about the thing.
The TAG officially resolved httpRange-14 by saying that disambiguation be-
tween these two types of resource should be done through the 303 See Other
HTTP header. The official resolution to Identity Crisis by the TAG is given below as:

￿ If an HTTP resource responds to a GET request with a 2xx response, then the

resource identified by that URI is an information resource;

￿ If an HTTP resource responds to a GET request with a 303 (See Other)

response, then the resource identified by that URI could be any resource;

￿ If an HTTP resource responds to a GET request with a 4xx (error) response,

then the nature of the resource is unknown.

To give an example, let's say an agent is trying to access a Semantic Web
URI that names a non-information resource, the Eiffel Tower itself, as illustrated
in Fig. 3.5 . Upon attempting to access that resource with an HTTP GET request
using its Semantic Web URI, since the Eiffel Tower itself is not an information
resource, no Web representations are directly available. Instead, the agent gets a
303 See Other that in turn redirects them to a documentation resource that
hosts Web representations about the Eiffel Tower, such as the information resource