[rest-practices] [Fwd: [rhevm-api] concatenating Link headers in response to entry-point HEAD method]

[Mark McLoughlin]

Hey,

I thought this had been discussed here, but I don't think so.

Eoghan found some issues with including multiple Link: headers.

I've seen something similar - a ruby client was only giving me a single
Link: header.

We've decided to concatenate our Link headers together on the server
side, as ugly as that is.

Cheers,
Mark.

-------- Forwarded Message --------
> From: Eoghan Glynn <eglynn at redhat.com>
> To: rhevm-api <rhevm-api at lists.fedorahosted.org>
> Subject: [rhevm-api] concatenating Link headers in response to
> entry-point HEAD method
> Date: Mon, 26 Apr 2010 09:11:24 +0100
> 
> 
> Folks,
> 
> We've noticed some funnies with the handling of multiple headers of the
> same name by various REST providers, with RESTeasy concatenating the
> header values into a comma separated list, and CXF JAX-RS seemingly
> dropping all but the last header instance.
> 
> In the light of the following chapter & verse from the spec:
> 
> "Multiple message-header fields with the same field-name MAY be present
> in a message if and only if the entire field-value for that header field
> is defined as a comma-separated list [i.e., #(values)]. It MUST be
> possible to combine the multiple header fields into one "field-name:
> field-value" pair, without changing the semantics of the message, by
> appending each subsequent field-value to the first, each separated by a
> comma. The order in which header fields with the same field-name are
> received is therefore significant to the interpretation of the combined
> field value, and thus a proxy MUST NOT change the order of these field
> values when a message is forwarded."[1]
> 
> It seems like a concatenation is the canonical form and least likely
> cause trouble along the way. So how about we simply squash together the
> Links set in the implementations of ApiResource.head()?
> 
> Cheers,
> Eoghan
> 
> 
> [1] http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2
> 
>     
> 
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