What's new in TclHttpd

3.5

Mostly this is a cleanup of the code and web pages to cleanly
separate out the core server from various sample applications and
demo code.  The default web site is defined by the htdocs and custom
subdirectories, and all the other stuff is organized under sampleapp.
There are some new security controls over the debug URL so you can
start up with that enabled and now worry about unauthorized access
to that interface.

3.4

The upload domain has seen many fixes as a result of actually using it.
Similarly, the Thread package has been updated to include some features
added when we embedded TclHttpd into a threaded management server.
The Doc module had some features added to template substitution
and directory listing.  You can control the scope at which a template
is subst'ed, and you and turn directory listings off.  There is also
simple support for the If-Modified-Since header.  See the ChangeLog
for details.

There is now a Virtual Host mechanism.  You can load additional
configuration files for different servers, and they are processed
in different Tcl interpreters within your main server application.

3.3

This adds a file upload domain handler. (upload.tcl)
Use Upload_Url to register the domain.  It takes a number
of arguments that are described in the lib/upload.tcl script.
A minimal call would be 

Upload_Url /upload /tmp/upload UploadTest

This will map the /upload URL to the upload domain.
If you post forms that contain <input type=file> elements to /upload, 
the files will be saved into /tmp/upload.  After they are saved,
the UploadTest procedure will be called.  It gets two arguments:
a list of form names and values, and a list of file names and 
content types.  See the UploadTest procedure in upload.tcl for
an example.

3.2

This adds a custom code directory that makes it easier to drop in
your applicaton-specific code without hand-editting the bin/httpd.tcl
and bin/httpdthread.tcl files.  Basically, all *.tcl files in the
custom code directory are sourced towards the end of startup.
Specify this directory with the -library command line switch,
or with the "library" tclhttpd.rc file parameter.  By default this
is the "custom" directory that now appears in the distribution.

The Url_PrefixInstall command has been generalized to take some
optional flags to enable some features on a per-domain basis.
The calling sequence is backward compatible:
    Url_PrefixInstall urlprefix tclcommand args
where the optional args are option-value pairs:
	-thread boolean
		If boolean is true, and threads are enabled,
		Then the domain handler is run in a thread.
		The default is FALSE.
	-readpost boolean
		If boolean is true, then the POST data is
		read in a non-blocking fashion before the
		domain handler is invoked, and appears in
		the data(query) variable.
		The default is TRUE, so turn this off
		if you have special post-data-reading code.
	-command tclcommand2
		This registers a command that is called
		at the very end of URL processing by the
		Httpd layer.  If the server decides to
		time out your domain handler or the request
		somehow aborts during processing, this
		provides a way to learn about that.  The
		command is called with two arguments, the
		socket handle on the connection, and an
		error string.  If the error string is empty,
		no error occurred.
		The default is no callback.

3.1

This is a cosmetic release that just changed all the "package provides" to
name packages with a leading "httpd::" to organize the package namespace better.

3.0

The 3.0* releases feature the following major structural changes:

Startup configuration.

There are now three files that define your server startup sequence:
In practice you may need to customize each of these.
httpd.tcl - the main startup script.  This processes command line
	arguments, opens the server sockets, does setuid and
	a other process-wide configuration.
httpdthread.tcl - a per-thread script that is also run by each thread.
	This has most of the "package require" calls and the
	various initialization calls that sets up your domian handlers.
	Oddly, this typically has Url_PrefixInstall commands, although
	these could also be in the httpd.tcl file.
tclhttpd.rc - a configuration file that sets various parameters.
	These include the port numbers, hostname, webmaster email, etc.

Standard Tcl Library dependency.

The server now depends on the ncgi, base64, and html packages
from the Standard Tcl Library.  See the TCLLIB file for
details about setting up the Standard Tcl Library.

Generalized Access Control.

The Url module now supports a more general access control
filter that is called before the Url is dispatched to
the domain handler.  This means, for example, you can use
.htaccess or .tclaccess file-based control for non-file
URLS like application-direct URLs.

Thread support.

You can now have your domain handler run in a worker thread.
The Url_PrefixInstall call takes an extra flag to specify this.
This requires that you have a Tclsh compiled with threads
enabled, plus you have the Thread extension.  Tcl 8.3.1
does not have all the right features to support passing sockets
between threads, so data is copied an extra time.  Tcl 8.4 will
have the right hooks (these are already in the CVS source base)
and the Thread extension will be updated to support it
in a future release.  Either way, the use of threads is nicely
hidden behind the Httpd_Return* APIs that you used before,
so you don't have to change your domain handlers to use threads.

SSL support.

This depends on the TLS extension by Matt Newman, as well as either
the OpenSSL or RSAREF crypto libraries.  If the server can
successfully "package require tls" then it will attempt to
start open an HTTPS port.  You must have the appropriate
certificates installed and edit the .rc file to reference
them.  The certs/README.ssl file has more details.

