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 (for
an overview of the templating system please refer to XAO::DO::Web::Page
description).
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 a 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, mod_perl, or PSGI.
* If used in mod_perl or PSGI 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 XAO::FS) 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
In most cases it should be enough to declare a dependency on XAO::Web in
your project's 'cpanfile'.
For a manual installation download an archive from a CPAN server near
you or use download links on <https://ejelta.com/xao/> and then install
it in the usual way:
perl Makefile.PL
make
make test
sudo make install
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 has
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 it 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 /opt/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!
In addition to reading this manual (or instead of reading it if you feel
too adventurous today) you can look at the generic site setup in the
misc/samplesite/ directory of the distribution archive. The sample site
also provides a very useful template to start any project with!
Configure your Apache server so that it would execute
/opt/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/ /opt/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.
The URL above looks bad and it exposes internal components - cgi-bin,
site name, etc. In production it is typically better to use mod_perl or
PSGI handlers to deal with that (see Apache::XAO and Plack::App::XAO).
In development an easy way to make the URL prettier (and matching
production) is by using Apache's mod_rewrite module. Here is how:
<VirtualHost 10.0.0.1:80>
ServerName test.company.com
ServerAlias test.company.com
<Directory /opt/xao/handlers>
Options ExecCGI
SetHandler cgi-script
</Directory>
RewriteEngine on
RewriteRule ^/images/(.*)$ \
/opt/xao/projects/mysite/images/$1 \
[L]
RewriteRule ^/(.*)$ \
/opt/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.
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 /opt/xao/projects with the name of your
site (/opt/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 => "https://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 XAO::DO::Config.
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
Andrew Maltsev -- am@ejelta.com -- <https://ejelta.com/xao/>
XAO::Web was created and is maintained by Andrew Maltsev. 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.
Copyright (c) 2001-2004 XAO Inc.
SEE ALSO
Recommended reading: XAO::DO::Web::Page (for templates language),
XAO::Objects (for object loading details), XAO::DO::Config (for site
config details), XAO::FS (for OO database interface),
XAO::DO::FS::Config, XAO::Web.