Re: [Jersey] Re: Hypermedia clarification

From: Jan Algermissen <>
Date: Tue, 16 Feb 2010 18:45:17 +0100

On Feb 16, 2010, at 6:24 PM, Markus Karg wrote:

>> Link is part of the representation metadata (that's its whole reason to
>> exist).
>> Content-Location is representation metadata for the URI of this
>> content.
>> Location is a response header used as part of the redirect aspects of
>> HTTP.
>> All three are data for describing transitions from here to there, when
>> used
>> according to the HTTP standards, and thus are part of the hypertext as
>> far
>> as REST is concerned. This is necessary for the support of hypermedia
>> representations in a format that does not allow embedded links or
>> overlays,
>> and for a lot of other reasons that I have no time to describe right
>> now.
> It's always enlighting to ask the master himself! So I am wrong, there are
> few (exactly these) headers that may contain links -- besides the entity
> itself. Great! But how shall a generic client (a) know which headers are
> used to transfer the link information and (b) that it has to check a header
> that is not even standardized?

A client can only look for headers (and media types for that matter) that it knows about.

How does the client developer know what headers to look for when coding to pursue a certain goal? Yes, the client needs some understanding of the set of hypermedia semantics the server makes use of.

Web browser implementers know that this set is HTML, stylesheets, images etc.

AtomPub client developers know that this set is application/atom+xml, application/atomsvc+xml and application/atomcat+xml

OpenSearch client developers know that this set is application/opensearch+xml, application/atom+xml and application/rss_xml


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 Jan Algermissen, Consultant
 NORD Software Consulting