[Tclhttpd] decodes URLs into references to functional modules called ''domains'', each of which is free to interpret the browser's [httpd] protocol interaction (including URLs) in any way it likes.

Access control and Basic authentication is performed before dispatching to a domain.

The following domains are standard with Tclhttpd:

   * [Tclhttpd Document Domain]: file access and templating.
   * [Tclhttpd Cgi Domain]: [CGI] processing.
   * [Tclhttpd Direct Domain]: direct calls of tcl procs yielding html and other data.
   * [Tclhttpd Redirect Domain]: support for redirecting URLs
   * [Tclhttpd Upload Domain]: file uploading of multipart/form-data.  See [File Upload example]

Other domains can be created per-site, by including the domain handling code in the custom directory.

   * examples here

A new domain can be registered by means of the [Url_PrefixInstall] command, which maps a URL prefix to a tcl proc which handles all URLs with the given prefix.

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[Tclhttpd] can roughly be functionally decomposed into
   1. http protocol interaction to get the request - '''http.tcl'''
   2. decoding a url - '''url.tcl'''
   3. Domain handling to generate content
   4. http protocol interaction to deliver the content - '''http.tcl'''
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[Category Tclhttpd]