NAME
XAO::Web - XAO Web Developer, dynamic content building suite
DESCRIPTION
XAO::Web is a part of XAO open source web services suite. It allows to
build dynamic web content using data, templates and external input.
The distinguishing feature of XAO::Web is in its modular design where
almost every aspect of functionality can be altered and alterations can
be re-used. No complex code is embedded in the templates which allows to
upgrade code and templates separately or maintain multiple visual
representations of the same functionality at the same time.
Aside from that most interesting features of XAO::Web are:
* Perl code is not mixed with templates. Templates can be normal HTML
files if no processing is required.
* A specific site can replace or modify standard XAO::Web objects if
required by overriding or extending their methods. You do not need
to re-implement entire object to make a site specific change.
In case of system object upgrade or bug fix there is no need to
alter site-specific changes normally.
* Site can create any extension objects or embed third-party
extensions as well.
* One server can serve arbitrary number of XAO::Web sites each with
however extended functionality without creating any conflicts. That
includes different modifications to the system objects for different
sites.
* Not limited to Web environment, allows to build any dynamic content
-- content of mail messages or reports for instance.
* Works with CGI or mod_perl (mod_perl is recommended for production
grade sites).
* If used in mod_perl mode improves performance by using caching of
configuration, parsed templates, database handlers and so on.
* XAO::Web is by default integrated with XAO::FS (see the XAO::FS
manpage) as a database layer, but this is not a requrement -- if for
any reason a different database must be used for a site it can be
easily and gracefully achieved.
* Hosting providers can allow their customers to build very complex
sites without allowing them to execute arbitrary code, by allowing
to modify only templates.
INSTALLATION
Download tarball from a CPAN server near you, from the master site (the
section on "/xao.com/" in the http: manpage) or using links on the
section on "/freshmeat.net/" in the http: manpage and then install it in
the usual way, just say:
perl Makefile.PL
make
make test
sudo make install
Saying "install XAO::Web" from the CPAN shell is a good way too:
perl -MCPAN -eshell
install XAO::Web
Using CPAN shell is usually the best way because all dependencies will
be resolved automatically. If you do manual installation then XAO::Web
depends on at least the following modules (look into Makefile.PL or just
watch closely the output of `perl Makefile.PL' for additional
dependencies):
XAO::Base
XAO::FS
Digest::MD5
Error
MIME::Lite
Test::Unit
When you run "perl Makefile.PL" you will be asked for XAO::Web test
database. That database is only used when you do `make test' and it have
to exist. It does not matter what is inside the database, it will be
completely wiped out for each test case. Normally the database should be
the same that you have used for XAO::FS tests and in case of MySQL is
usually 'test' or 'test_fs'.
The directory where templates get installed is the same that you gave to
XAO::Base when you installed it. Normally that directory is
/usr/local/xao -- we will assume that for the rest of the document.
FIRST-TIME RUNNING AND TESTING
You are almost there. Now is the time to try it!
Configure your Apache server so that it would execute
/usr/local/xao/handlers/xao-apache.pl when someone types URL like
http://test.company.com/cgi-bin/xao-apache.pl. Here is an example of a
virtual host configuration for that (or you can simply sym-link
xao-apache.pl to your existing cgi-bin directory if you have one):
<VirtualHost 10.0.0.1:80>
ServerName test.company.com
ScriptAlias /cgi-bin/ /usr/local/xao/handlers/
</VirtualHost>
After you configure and re-start your web-server point your browser at
http://test.company.com/cgi-bin/xao-apache.pl/mysite/ -- you should be
able to see the default page template processed by XAO::Web. If you do
not see it -- you might want to look into apache error log, usually
there is some additional information there.
In the URL you used to look at the default page includes 'mysite' as a
site name. In this case it can be anything you want, nothing depends on
the name because your site does not yet have any specific templates,
objects or configuration. We will get back to customizing your site
later.
Now let us look into the URL - it does not look good, does it? It
includes cgi-bin, site name and generally looks ugly, we agree. The way
to deal with it currently is to use mod_rewrite to hide that into Apache
configuration. We are working on the real mod_perl module that will not
require mod_rewrite, you should expect it with the next release of
XAO::Web.
Here is how to configure Apache with mod_rewrite in the meantime:
<VirtualHost 10.0.0.1:80>
ServerName test.company.com
ServerAlias test.company.com
<Directory /usr/local/xao/handlers>
Options ExecCGI
SetHandler cgi-script
</Directory>
RewriteEngine on
RewriteRule ^/images/(.*)$ \
/usr/local/xao/projects/mysite/images/$1 \
[L]
RewriteRule ^/(.*)$ \
/usr/local/xao/handlers/xao-apache.pl/mysite/$1 \
[L]
</VirtualHost>
That leaves everything in /images/ to be processed by the web server in
the usual way and maps everything else to XAO::Web handler. Restart
Apache and try going to just http://test.company.com/ now -- you should
see the same default page as before.
And finally, here is an example of mod_perl configuration, you should
use it for production grade sites. The only difference is in <Directory>
block.
<VirtualHost 10.0.0.1:80>
ServerName test.company.com
ServerAlias test.company.com
<Directory /usr/local/xao/handlers>
Options ExecCGI
SetHandler perl-script
PerlHandler Apache::Registry
PerlSendHeader Off
</Directory>
RewriteEngine on
RewriteRule ^/images/(.*)$ \
/usr/local/xao/projects/mysite/images/$1 \
[L]
RewriteRule ^/(.*)$ \
/usr/local/xao/handlers/xao-apache.pl/mysite/$1 \
[L]
</VirtualHost>
That is it, if you got so far your installation of XAO::Web works fine
and you can move on to actually building a custom web site.
SITE DEVELOPMENT
Before you go any further it is recommended that you keep cgi-bin
configuration sample from the examples above as opposed to mod_perl.
Mod_perl development has its own peculiarities related to caching of
modules and content and you can get back to that later. Cgi-bin based
configurations are usually much easier to develop and debug.
Here is a couple of steps to start the development of a new site.
1 Choose a name for your site. It have to start with a lowercase
letter and may contain letters, digits and underscore signs. Let's
assume you've chosen "mysite" as a name.
2 Create a sub-directory in /usr/local/xao/projects with the name of
your site (/usr/local/xao/projects/mysite in our case). This
directory is the home directory of your site. Everything else below
is relative to that directory. For simplicity you might want to
sym-link that directory into your home directory.
3 Create a sub-directory named 'objects'. Place a configuration file
called 'Config.pm' inside of it. There is a couple of requrements
for that file:
* Package name have to be 'XAO::DO::Config'.
* Usually it defines an init() method that will initialize site
configuration. In mod_perl environment that method will be
called only once when the site is initialized for the first
time. That means that init() is a good place to open connection
to a database and it is recommended to do that as most of XAO
modules require database connection to work properly.
Here is an example of configuration module Config.pm for "mysite"
site:
# Configuration for mysite
#
package XAO::DO::Config;
use strict;
use XAO::Objects;
# Inheritance from the system Config object
#
use base XAO::Objects->load(objname => 'Config', baseobj => 1);
# Site configuration values. A lot of stuff can be stored here for
# different modules, base_url is not required, but recommended.
#
my %data=(
base_url => "http://test.company.com",
base_url_secure => "http://test.company.com",
);
##
# Initializing configuration object for our site
#
sub init {
my $self=shift;
# Creating a database configuration object and embedding it into our
# configuration, see below for explanation
#
my $fsconfig = XAO::Objects->new(
objname => 'FS::Config',
odb_args => {
dsn => 'OS:MySQL_DBI:test_fs',
user => 'test',
password => 'test',
}
);
$self->embed(fs => $fsconfig);
# Storing configuration into embedded hash
#
$self->embedded('hash')->fill(\%data);
# And finally calling base class' init() method
#
$self->SUPER::init();
}
1;
For the more detailed description of `embedding' and initialization
process in general please refer to the XAO::DO::Config manpage.
4 At that point you should already be able to see your new site in
your browser. Just point it to
http://test.company.com/cgi-bin/xao-apache.pl/mysite/ or just
http://test.company.com/ depending on your Apache configuration.
But in order to do something useful you normally need to create one
more directory - 'templates'. That directory will contain all
templates of your site and unless you use some extended features of
XAO::Web the layout of files in this directory directly translates
into URIs.
Nothing else is used by XAO::Web and usually you would also create
directories like 'images' or 'static'; put your site to CVS version
control or make some kind of installation tools for it. It is all up
to you.
This is it. Try placing an index.html file into your 'templates'
directory and go to browser to check how it appears.
AUTHORS
Copyright (c) 2000-2001 XAO Inc.
XAO::Web was created and is maintained by Andrew Maltsev <am@xao.com>.
Creating of XAO::Web would not be possible without valuable comments and
ideas from everybody on our team and especially from Marcos Alves, Bil
Drury, Brian Despain and Jason Shupe.
SEE ALSO
Recommended reading: the XAO::Web manpage, the XAO::Objects manpage, the
XAO::DO::Config manpage, the XAO::FS manpage, the XAO::DO::FS::Config
manpage.