HTML::Mason(3) User Contributed Perl Documentation HTML::Mason(3)NAME
Mason - High-performance, dynamic web site authoring system
SYNOPSIS
PerlModule HTML::Mason::ApacheHandler
<Location />
SetHandler perl-script
PerlHandler HTML::Mason::ApacheHandler
</Location>
DESCRIPTION
Mason is a tool for building, serving and managing large web sites. Its
features make it an ideal backend for high load sites serving dynamic
content, such as online newspapers or database driven e-commerce sites.
Actually, Mason can be used to generate any sort of text, whether for a
web site or not. But it was originally built for web sites and since
that's why most people are interested in it, that is the focus of this
documentation.
Mason's various pieces revolve around the notion of "components''. A
component is a mix of HTML, Perl, and special Mason commands, one
component per file. So-called "top-level" components represent entire
web-pages, while smaller components typically return HTML snippets for
embedding in top-level components. This object-like architecture
greatly simplifies site maintenance: change a shared component, and you
instantly changed all dependant pages that refer to it across a site
(or across many virtual sites).
Mason's component syntax lets designers separate a web page into
programmatic and design elements. This means the esoteric Perl bits can
be hidden near the bottom of a component, preloading simple variables
for use above in the HTML. In our own experience, this frees content
managers (i.e., non-programmers) to work on the layout without getting
mired in programming details. Techies, however, still enjoy the full
power of Perl.
Mason works by intercepting innocent-looking requests (say,
http://www.yoursite.com/index.html) and mapping them to requests for
Mason components. Mason then compiles the component, runs it, and
feeds the output back to the client.
Consider this simple Mason component:
% my $noun = 'World';
Hello <% $noun %>!
How are ya?
The output of this component is:
Hello World!
How are ya?
In this component you see a mix of standard HTML and Mason elements.
The bare '%' prefixing the first line tells Mason that this is a line
of Perl code. One line below, the embedded <% ... %> tag gets replaced
with the return value of its contents, evaluated as a Perl expression.
Beyond this trivial example, components can also embed serious chunks
of Perl code (say, to pull records from a database). They can also call
other components, cache results for later reuse, and perform all the
tricks you expect from a regular Perl program.
MASON 1 (HTML::MASON) VERSUS MASON 2 (MASON)
Version 1 of Mason --HTML::Mason-- has been around since 1998, is in
wide use, and is very stable. However it has not changed much in years
and is no longer actively developed.
Version 2 of Mason -- Mason -- was released in February of 2011. It is
being very actively developed and has a much more modern architecture.
If you are just starting out, we recommend you give Mason 2 a try.
For a summary of differences between Mason 1 and 2 see
http://www.openswartz.com/2011/02/21/announcing-mason-2/
INSTALLATION
Mason has been tested under Linux, FreeBSD, Solaris, HPUX, and Win32.
As an all-Perl solution, it should work on any machine that has working
versions of Perl 5.00503+, mod_perl, and the required CPAN modules.
Mason has a standard MakeMaker-driven installation. See the README file
for details.
CONFIGURING MASON
This section assumes that you are able to install and configure a
mod_perl server. Relevant documentation is available at
http://www.apache.org (Apache) and http://perl.apache.org (mod_perl).
The mod_perl mailing list, archive, and guide are also great resources.
The simplest configuration of Mason requires a few lines in your
httpd.conf:
PerlModule HTML::Mason::ApacheHandler
<Location />
SetHandler perl-script
PerlHandler HTML::Mason::ApacheHandler
</Location>
The PerlModule directive simply ensures that the Mason code is loaded
in the parent process before forking, which can save some memory when
running mod_perl.
The <Location> section routes all requests to the Mason handler, which
is a simple way to try out Mason. A more refined setup is discussed in
the Controlling Access via Filename Extension section of the
administrator's manual.
Once you have added the configuration directives, restart the server.
First, go to a standard URL on your site to make sure you haven't
broken anything. If all goes well you should see the same page as
before. If not, recheck your Apache config files and also tail your
server's error log.
If you are getting "404 Not Found" errors even when the files clearly
exist, Mason may be having trouble with your document root. One
situation that will unfortunately confuse Mason is if your document
root goes through a symbolic link. Try expressing your document root in
terms of the true filesystem path.
Next, try adding the tag <% 2+2 %> at the top of some HTML file. If you
reload this page and see a "4", Mason is working!
DOCUMENTATION ROADMAP
Once Mason is on its feet, the next step is to write a component or
two. The Mason Developer's Manual is a complete tutorial for writing,
using, and debugging components. A reference companion to the
Developer's Manual is the Request API documentation,
HTML::Mason::Request.
Whoever is responsible for setting up and tuning Mason should read the
Administrator's Manual, though developers will also benefit from
reading it as well. This document covers more advanced configuration
scenarios and performance optimization. The reference companion to the
Administrator's manual is the Parameters Reference, which describes all
the parameters you can use to configure Mason.
Most of this documentation assumes that you're running Mason on top of
mod_perl, since that is the most common configuration. If you would
like to run Mason via a CGI script, refer to the
HTML::Mason::CGIHandler documentation. If you are using Mason from a
standalone program, refer to the Using Mason from a Standalone Script
section of the administrator's manual.
There is also a book about Mason, Embedding Perl in HTML with Mason, by
Dave Rolsky and Ken Williams, published by O'Reilly and Associates.
The book's website is at http://www.masonbook.com/. This book goes
into detail on a number of topics, and includes a chapter of recipes as
well as a sample Mason-based website.
AUTHORS
Jonathan Swartz <swartz@pobox.com>, Dave Rolsky <autarch@urth.org>, Ken
Williams <ken@mathforum.org>, John Williams <williams@tni.com>
COPYRIGHT
Copyright (c) 1998-2005 Jonathan Swartz. All rights reserved. This
program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
The full text of the license can be found in the LICENSE file included
with this module.
SEE ALSO
HTML::Mason::Devel, HTML::Mason::Admin
perl v5.14.2 2012-02-05 HTML::Mason(3)
