The XML FAQ

The only changes needed are to make sure your server serves up .xml, .css, .dtd, .xsl, and whatever other file types you will use as the correct MIME content (media) types.

The details of the settings are specified in RFC 3023. Most new versions of Web server software come preset.

If not, all that is needed is to edit the mime-types file (or its equivalent: as a server operator you already know where to do this, right?) and add or edit the relevant lines for the right media types. In some servers (eg Apache), individual content providers or directory owners may also be able to change the MIME types for specific file types from within their own directories by using directives in a .htaccess file. The media types required are:

• text/xml for XML documents which are ‘readable by casual users’;

• application/xml for XML documents which are ‘unreadable by casual users’;

• text/xml-external-parsed-entity for external parsed entities such as document fragments (eg separate chapters which make up a book) subject to the readability distinction of text/xml;

• application/xml-external-parsed-entity for external parsed entities subject to the readability distinction of application/xml;

• application/xml-dtd for DTD files and modules, including character entity sets.

The RFC has further suggestions for the use of the +xml media type suffix for identifying ancillary files such as XSLT (application/xslt+xml).

If you run scripts generating XHTML which you wish to be treated as XML rather than HTML, they may need to be modified to produce the relevant Document Type Declaration as well as the right media type if your application requires them to be validated.