= Accept Header

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The RO spec uses the standard `Accept` header for content negotiation, and defines its own "profile" for the standard representations; these take the form:

[source]
----
Accept: application/json;profile="urn:org.restfulobjects:repr-types/xxx"
----

where "xxx" varies by resource.
The detail can be found in link:https://www.restfulobjects.org/spec/1.0/section-a/chapter-02.html#_2-4-1-representationtype-profile-parameter[section 2.4.1] of the RO spec.

The "Causeway" profile allows the client to request simplified representations for the most frequently accessed resources.
This is done by specifying an `Accept` header of:

[source]
----
Accept: application/json;profile="urn:org.apache.causeway/v2"
----

Not every resource supports this header, but the most commonly accessed ones do.
In each case the server will set the
`Content-Type` header so that the client knows how to process the representation.

The link:https://www.youtube.com/watch?v=HMSqapQDY_4[screencast] demonstrates the feature.

The sections below explain in a little more detail what is returned when this profile is activated.


