mod_xhtml_neg home

This module for the the Apache HTTP server gives it the ability to correctly negotiate content types for XHTML documents. Without negotiation, these would be sent as text/html. For browsers that support XHTML as an XML document, the content can (and should) be sent as application/xhtml+xml. See the W3C's technical note for details.

Also see RFC 3236 for some of the technicalities of correctly negotiating XHTML documents.

One solution that's been seen around the web in a few places is to use the Apache mod_rewrite module to sniff the Accept: header in HTTP requests. This is crude but will work most of the time. See an example of this at Greytower Technologies.

This Apache module does similar negotiation, but with the following advantages:

• It can correctly handle relative quality values for different content-types based on the browser's Accept header
• It will correctly send Vary headers and a unique ETag header for each response type, thus ensuring proxy caches will work correctly
• Can perform character set negotiation based on the Accept-Charset header, taking into account the default character sets defined in RFC 2616 and RFC 3023
• Can perform negotiation based on XHTML profiles using the optional "profile" parameter in the Accept header.*
• Will correctly degrade caching for HTTP 1.0 proxies

*Profiles are XML namespaces that refer to the XHTML variants, such as XHTML Basic, XHTML Mobile Profile, and so on. The profile parameter was introduced in section 8 of RFC 3236.

Release

The current release for Apache 1.3 is 1.0. This is a stable release. Download the source code for Apache 1.3 from the SourceForge site.

The current release for Apache 2.x is 1.0a. This is a minor bugfix release. Download the source code for Apache 2.x from the SourceForge site.

Resources

• The download page of the current release
• The status page
• Directives for this module
• A sample configuration file
• Links to related sites and resources
• Doxygen generated documentation for the 1.3 and 2.x server releases

Contact

For any further information, please feel free to contact me, Nicholas Cull.