[DAS2] Re: New problem with content-type header in DAS/2 server responses!

[Allen Day]

> What does the "X-DAS-Server" get you that the normal "Server:" doesn't
> get you?  What's the use case?

I don't know.  The absence of this header was actually reported by Dasypus
output sent to me by you on May 26, 2005.  Here's a snippet of the Dasypus
diagnostics, followed by a comment from you:

"Date: Thu, 26 May 2005 12:29:32 -0600
From: Andrew Dalke <dalke at dalkescientific.com>
To: DAS/2 <das2 at portal.open-bio.org>
Subject: [DAS2] dasypus status
[...]
WARNING: Adding X-DAS-Server header 'gmod/0.0'

The prototype doesn't mention the DAS server used.  I stick one
in based on the host name.
[...]"

> Why is the "X-DAS-Version" at all important?  What's important is the
> data content.  It's the document return type/version that's important
> and not the server version.

It was actually originally (as far as I can tell from my email archive)
discussed, along with X-DAS-Status in an email from Lincoln on May 21,
2004, and forwarded to me on August 12, 2004:

"-----Original Message-----
From: Lincoln Stein [mailto:lstein at cshl.edu] 
Sent: Friday, May 21, 2004 1:22 PM
To: edgrif at sanger.ac.uk; Gregg_Helt at affymetrix.com; avc at sanger.ac.uk;
gilmanb at mac.com; dalke at dalkescientific.com
Cc: lstein at cshl.edu; allen.day at ucla.edu
Subject: DAS/2 notes
[...]
In addition to the standard HTTP response headers, DAS servers return the
following HTTP headers:

    X-DAS-Version: DAS/2.0
    X-DAS-Status:  XXX status code
[...]"

> But I mentioned most of these over a year ago
>    http://portal.open-bio.org/pipermail/das/2004-September/000814.html
> 
> In summary:
>    - no support for direct web browser access to a URL, expect with a
>        likely use case;
>    - keep the default response in an XML format
>    - change that XML content-type to "application/x-das-*+xml" instead 
> of "text/*"
>    - have no requirement for new, DAS-specific headers

This discussion suggests we need for a more formal process of modifying
the client and server implementations, e.g. modify spec first and commit,
then update code.

-Allen