Titanium(3) User Contributed Perl Documentation Titanium(3)NAMETitanium - A strong, lightweight web application framework
SYNOPSIS
Coding
# In "WebApp.pm"...
package WebApp;
use base 'Titanium';
sub setup {
my $c = shift;
$c->start_mode('form_display');
$c->run_modes([qw/
form_display
form_process
/]);
}
sub form_display {
my $c = shift;
my $errs = shift;
my $t = $c->load_tmpl;
$t->param($errs) if $errs;
return $t->output;
}
sub form_process {
my $c = shift;
# Validate the form against a profile. If it fails validation, re-display
# the form for the user with their data pre-filled and the errors highlighted.
my ($results, $err_page) = $c->check_rm('form_display','_form_profile');
return $err_page if $err_page;
return $c->forward('form_success');
}
# Return a Data::FormValidator profile
sub _form_profile {
my $c = shift;
return {
required => 'email',
};
}
sub form_success { ... }
1;
### In "webapp.cgi"...
use WebApp;
my $c = WebApp->new();
$c->run();
Inside the run modes, the following methods are available:
$c->query; # A query object. CGI.pm by default.
$c->redirect('http://othersite.com'); # Basic redirection
$c->dbh; # DBI database handle
$c->session(); # A CGI::Session object
$c->check_rm; # Form validation with Data::FormValidator
$c->cfg('root_uri'); # Config file access (YAML, Perl or INI formats)
$c->fill_form; # Form filling with HTML::FillInForm
$c->error( title => '..', msg => '..' ); # Easy error page generation
$c->stream_file($file); # file streaming
$c->log; # A Log::Dispatch object
Development and Testing
Easily setup the project skeleton using the bundled cgiapp-starter
script.
In development you can turn on a debugging screen and a developer pop-
up to quickly catch code, html and performance issues, thanks to
CGI::Application::Plugin::DebugScreen and
CGI::Application::Plugin::DevPopup.
For automated testing, Test::WWW::Mechanize::CGIApp is bundled,
allowing you to functionally test your web application without
involving a full web server. If you'd rather test against full web
server, Test::WWW::Mechanize is there, too.
Dispatching with Clean URIs
Modern web frameworks dispense with cruft in URIs. Instead of:
/cgi-bin/item.cgi?rm=view&id=15
A clean URI to describe the same resource might be:
/item/15/view
The process of mapping these URIs to run modes is called dispatching
and is handled by CGI::Application::Dispatch. It comes with a default
dispatch table that automatically creates URLs in this pattern for you:
/app/module_name/run_mode
There's plenty of flexibility to design your own URIs if you'd like.
Elements of Titanium
* Titanium is solid and mature. While it has a new name, the reality is
that Titanium is simply a more user-friendly packaging of the mature
CGI::Application framework and some useful plugins. These packages have
already been refined and vetted. The seed framework was first released
in 2000 and by 2005 was mature. Titanium contains no real code of its
own, and there is no intention to do so in the future. Instead, we may
select other mature plugins to include in the future. Other "Titanium
alloys" in the "Titanium::Alloy::" name space may also come to exist,
following the same philosophy, but choosing to bundle a different
combination of plugins.
* Titanium is lightweight. Titanium has a very light core and the
plugins it uses employ lazy-loading whenever possible. That means that
while we have built-in database plugin, we don't have to load DBI or
make a database connection until you actually use the database
connection. Titanium runs well in a plain CGI environment and provides
excellent performance in a persistent environment such as FastCGI or
mod_perl. Titanium apps are compatible with the dozens of published
plugins for CGI::Application, so you can add additional features as
your needs evolve.
DESCRIPTION
It is intended that your Application Module will be implemented as a
sub-class of Titanium. This is done simply as follows:
package My::App;
use base 'Titanium';
Notation and Conventions
For the purpose of this document, we will refer to the following
conventions:
WebApp.pm : The Perl module which implements your Application Module class.
WebApp : Your Application Module class; a sub-class of Titanium.
webapp.cgi : The Instance Script which implements your Application Module.
$c : Used in instance methods to pass around the
current object. (Sometimes referred as "$self" in other projects.)
Think of the "$c" as short for "controller".
Script/Dispatching Methods
By inheriting from Titanium you have access to a number of built-in
methods. The following are those which are expected to be called from
your Instance Script or through your CGI::Application::Dispatch
dispatcher.
new()
The new() method is the constructor for a Titanium. It returns a
blessed reference to your Application Module class. Optionally, new()
may take a set of parameters as key => value pairs:
my $c = WebApp->new(
TMPL_PATH => 'App/',
PARAMS => {
'custom_thing_1' => 'some val',
'another_custom_thing' => [qw/123 456/]
}
);
This method may take some specific parameters:
TMPL_PATH - This optional parameter defines a path to a directory of
templates. This is used by the load_tmpl() method (specified below),
and may also be used for the same purpose by other template plugins.
This run-time parameter allows you to further encapsulate instantiating
templates, providing potential for more re-usability. It can be either
a scalar or an array reference of multiple paths.
QUERY - This optional parameter allows you to specify an already-
created CGI query object. Under normal use, Titanium will instantiate
its own CGI.pm query object. Under certain conditions, it might be
useful to be able to use one which has already been created.
PARAMS - This parameter, if used, allows you to set a number of custom
parameters at run-time. By passing in different values in different
instance scripts which use the same application module you can achieve
a higher level of re-usability. For instance, imagine an application
module, "Mailform.pm". The application takes the contents of a HTML
form and emails it to a specified recipient. You could have multiple
instance scripts throughout your site which all use this "Mailform.pm"
module, but which set different recipients or different forms.
One common use of instance scripts is to provide a path to a config
file. This design allows you to define project wide configuration
objects used by many several instance scripts. There are several
plugins which simplify the syntax for this and provide lazy loading.
Here's an example using CGI::Application::Plugin::ConfigAuto, which
uses Config::Auto to support many configuration file formats.
my $app = WebApp->new(PARAMS => { cfg_file => 'config.pl' });
# Later in your app:
my %cfg = $c->cfg()
# or ... $c->cfg('HTML_ROOT_DIR');
See the list of of plugins below for more config file integration
solutions.
run()
The run() method is called upon your Application Module object, from
your Instance Script. When called, it executes the functionality in
your Application Module.
my $c = WebApp->new;
$c->run;
This method determines the application state by looking at the dispatch
table, as described in CGI::Application::Dispatch.
Once the mode has been determined, run() looks at the hash stored in
run_modes() and finds the subroutine which is tied to a specific hash
key. If found, the function is called and the data returned is
print()'ed to STDOUT and to the browser. If the specified mode is not
found in the run_modes() table, run() will croak(). This 'death' can
possibly be captured and handled using "error_mode()", described below.
Essential Method to Override
Titanium implements some methods which are expected to be overridden by
implementing them in your sub-class module. One of these is essential
to do:
setup()
This method is called by the inherited new() constructor method. The
setup() method should be used to define the following property/methods:
start_mode() - string containing the default run mode.
run_modes() - hash table containing mode => function mappings.
error_mode() - string containing the error mode.
tmpl_path() - string or array reference containing path(s) to template directories.
Your setup() method may call any of the instance methods of your
application. This function is a good place to define properties
specific to your application via the $c->param() method.
Your setup() method might be implemented something like this:
sub setup {
my $c = shift;
$c->start_mode('putform');
$c->run_modes([qw/
form
form_process
/]);
}
Essential Application Methods
The following methods are inherited from Titanium, and are available to
be called by your application within your Application Module. They are
called essential because you will use all are most of them to get any
application up and running. These functions are listed in alphabetical
order.
load_tmpl()
my $tmpl_obj = $c->load_tmpl;
my $tmpl_obj = $c->load_tmpl('some.html');
my $tmpl_obj = $c->load_tmpl( \$template_content );
my $tmpl_obj = $c->load_tmpl( FILEHANDLE );
This method takes the name of a template file, a reference to template
data or a FILEHANDLE and returns an HTML::Template object. If the
filename is undefined or missing, Titanium will default to trying to
use the current run mode name, plus the extension ".html".
If you use the default template naming system, you should also use
CGI::Application::Plugin::Forward, which simply helps to keep the
current name accurate when you pass control from one run mode to
another.
( For integration with other template systems and automated template
names, see "Alternatives to load_tmpl() below. )
When you pass in a filename, the HTML::Template->new_file() constructor
is used for create the object. When you pass in a reference to the
template content, the HTML::Template->new_scalar_ref() constructor is
used and when you pass in a filehandle, the
HTML::Template->new_filehandle() constructor is used.
Refer to HTML::Template for specific usage of HTML::Template.
If tmpl_path() has been specified, load_tmpl() will set the
HTML::Template "path" option to the path(s) provided. This further
assists in encapsulating template usage.
The load_tmpl() method will pass any extra parameters sent to it
directly to HTML::Template->new_file() (or new_scalar_ref() or
new_filehandle()). This will allow the HTML::Template object to be
further customized:
my $tmpl_obj = $c->load_tmpl('some_other.html',
die_on_bad_params => 0,
cache => 1
);
Note that if you want to pass extra arguments but use the default
template name, you still need to provide a name of "undef":
my $tmpl_obj = $c->load_tmpl(undef',
die_on_bad_params => 0,
cache => 1
);
Alternatives to load_tmpl()
If your application requires more specialized behavior than this, you
can always replace it by overriding load_tmpl() by implementing your
own load_tmpl() in your Titanium sub-class application module.
First, you may want to check out the template related plugins.
CGI::Application::Plugin::TT focuses just on Template Toolkit
integration, and features pre-and-post features, singleton support and
more.
param()
$c->param('pname', $somevalue);
The param() method provides a facility through which you may set
application instance properties which are accessible throughout your
application.
The param() method may be used in two basic ways. First, you may use
it to get or set the value of a parameter:
$c->param('scalar_param', '123');
my $scalar_param_values = $c->param('some_param');
Second, when called in the context of an array, with no parameter name
specified, param() returns an array containing all the parameters which
currently exist:
my @all_params = $c->param();
The param() method also allows you to set a bunch of parameters at once
by passing in a hash (or hashref):
$c->param(
'key1' => 'val1',
'key2' => 'val2',
'key3' => 'val3',
);
The param() method enables a very valuable system for customizing your
applications on a per-instance basis. One Application Module might be
instantiated by different Instance Scripts. Each Instance Script might
set different values for a set of parameters. This allows similar
applications to share a common code-base, but behave differently. For
example, imagine a mail form application with a single Application
Module, but multiple Instance Scripts. Each Instance Script might
specify a different recipient. Another example would be a web bulletin
boards system. There could be multiple boards, each with a different
topic and set of administrators.
The new() method provides a shortcut for specifying a number of run-
time parameters at once. Internally, Titanium calls the param() method
to set these properties. The param() method is a powerful tool for
greatly increasing your application's re-usability.
query()
my $q = $c->query();
my $remote_user = $q->remote_user();
This method retrieves the CGI.pm query object which has been created by
instantiating your Application Module. For details on usage of this
query object, refer to CGI. Titanium is built on the CGI module.
Generally speaking, you will want to become very familiar with CGI.pm,
as you will use the query object whenever you want to interact with
form data.
When the new() method is called, a CGI query object is automatically
created. If, for some reason, you want to use your own CGI query
object, the new() method supports passing in your existing query object
on construction using the QUERY attribute.
run_modes()
# The common usage: an arrayref of run mode names that exactly match subroutine names
$c->run_modes([qw/
form_display
form_process
/]);
# With a hashref, use a different name or a code ref
$c->run_modes(
'mode1' => 'some_sub_by_name',
'mode2' => \&some_other_sub_by_ref
);
This accessor/mutator specifies a lookup table for the application
states, using the syntax examples above. It returns the dispatch table
as a hash.
The run_modes() method may be called more than once. Additional values
passed into run_modes() will be added to the run modes table. In the
case that an existing run mode is re-defined, the new value will
override the existing value. This behavior might be useful for
applications which are created via inheritance from another
application, or some advanced application which modifies its own
capabilities based on user input.
The run() method uses the data in this table to send the application to
the correct function as determined by the dispatcher, as described in
CGI::Application::Dispatch. These functions are referred to as "run
mode methods".
The hash table set by this method is expected to contain the mode name
as a key. The value should be either a hard reference (a subref) to
the run mode method which you want to be called when the application
enters the specified run mode, or the name of the run mode method to be
called:
'mode_name_by_ref' => \&mode_function
'mode_name_by_name' => 'mode_function'
The run mode method specified is expected to return a block of text
(e.g.: HTML) which will eventually be sent back to the web browser.
The run mode method may return its block of text as a scalar or a
scalar-ref.
An advantage of specifying your run mode methods by name instead of by
reference is that you can more easily create derivative applications
using inheritance. For instance, if you have a new application which
is exactly the same as an existing application with the exception of
one run mode, you could simply inherit from that other application and
override the run mode method which is different. If you specified your
run mode method by reference, your child class would still use the
function from the parent class.
An advantage of specifying your run mode methods by reference instead
of by name is performance. Dereferencing a subref is faster than
eval()-ing a code block. If run-time performance is a critical issue,
specify your run mode methods by reference and not by name. The speed
differences are generally small, however, so specifying by name is
preferred.
Specifying the run modes by array reference:
$c->run_modes([ 'mode1', 'mode2', 'mode3' ]);
Is is the same as using a hash, with keys equal to values
$c->run_modes(
'mode1' => 'mode1',
'mode2' => 'mode2',
'mode3' => 'mode3'
);
Often, it makes good organizational sense to have your run modes map to
methods of the same name. The array-ref interface provides a shortcut
to that behavior while reducing verbosity of your code.
Note that another importance of specifying your run modes in either a
hash or array-ref is to assure that only those Perl methods which are
specifically designated may be called via your application.
Application environments which don't specify allowed methods and
disallow all others are insecure, potentially opening the door to
allowing execution of arbitrary code. Titanium maintains a strict
"default-deny" stance on all method invocation, thereby allowing secure
applications to be built upon it.
IMPORTANT NOTE ABOUT RUN MODE METHODS
Your application should *NEVER* print() to STDOUT. Using print() to
send output to STDOUT (including HTTP headers) is exclusively the
domain of the inherited run() method. Breaking this rule is a common
source of errors. If your program is erroneously sending content
before your HTTP header, you are probably breaking this rule.
THE RUN MODE OF LAST RESORT: "AUTOLOAD"
If Titanium is asked to go to a run mode which doesn't exist, by
default it will return an error page to the user, implemented like
this:
return $c->error(
title => 'The requested page was not found.',
msg => "(The page tried was: ".$c->get_current_runmode.")"
);
See CGI::Application::Plugin::ErrorPage for more details on the built-
in error page system. If this is not your desired behavior for
handling unknown run mode requests, implement your own run mode with
the reserved name "AUTOLOAD":
$c->run_modes(
"AUTOLOAD" => \&catch_my_exception
);
Before Titanium invokes its own error page handling it will check for
the existence of a run mode called "AUTOLOAD". If specified, this run
mode will in invoked just like a regular run mode, with one exception:
It will receive, as an argument, the name of the run mode which invoked
it:
sub catch_my_exception {
my $c = shift;
my $intended_runmode = shift;
my $output = "Looking for '$intended_runmode', but found 'AUTOLOAD' instead";
return $output;
}
This functionality could be for more sophisticated application
behaviors.
start_mode()
$c->start_mode('mode1');
The start_mode contains the name of the mode as specified in the
run_modes() table. Default mode is "start". The mode key specified
here will be used whenever the value of the CGI form parameter
specified by mode_param() is not defined. Generally, this is the first
time your application is executed.
tmpl_path()
$c->tmpl_path('/path/to/some/templates/');
This access/mutator method sets the file path to the directory (or
directories) where the templates are stored. It is used by load_tmpl()
to find the template files, using HTML::Template's "path" option. To
set the path you can either pass in a text scalar or an array reference
of multiple paths.
More Methods to override
Several more non-essential methods are useful to declare in your
application class, or in a project "super class" that inherits from
your Titanium only to serve in turn as a base class for project
modules. These additional methods are as follows:
teardown()
If implemented, this method is called automatically after your
application runs. It can be used to clean up after your operations. A
typical use of the teardown() function is to disconnect a database
connection which was established in the setup() function, or flush open
session data. You could also use the teardown() method to store state
information about the application to the server.
cgiapp_init()
If implemented, this method is called automatically right before the
setup() method is called. The cgiapp_init() method receives, as its
parameters, all the arguments which were sent to the new() method.
An example of the benefits provided by utilizing this hook is creating
a custom "application super-class" from which which all your web
applications would inherit, instead of directly from Titanium.
Consider the following:
# In MySuperclass.pm:
package MySuperclass;
use base 'Titanium';
sub cgiapp_init {
my $c = shift;
# Perform some project-specific init behavior
# such as to load settings from a database or file.
}
# In MyApplication.pm:
package MyApplication;
use base 'MySuperclass';
sub setup { ... }
sub teardown { ... }
# The rest of your Titanium-based follows...
By using Titanium and the cgiapp_init() method as illustrated, a suite
of applications could be designed to share certain characteristics,
creating cleaner code.
cgiapp_prerun()
If implemented, this method is called automatically right before the
selected run mode method is called. This method provides an optional
pre-runmode hook, which permits functionality to be added at the point
right before the run mode method is called. The value of the run mode
is passed into cgiapp_prerun().
This could be used by a custom "application super-class" from which all
your web applications would inherit, instead of Titanium.
Consider the following:
# In MySuperclass.pm:
package MySuperclass;
use base 'Titanium';
sub cgiapp_prerun {
my $c = shift;
# Perform some project-specific init behavior
# such as to implement run mode specific
# authorization functions.
}
# In MyApplication.pm:
package MyApplication;
use base 'MySuperclass';
sub setup { ... }
sub teardown { ... }
# The rest of your Titanium-based follows...
It is also possible, within your cgiapp_prerun() method, to change the
run mode of your application. This can be done via the prerun_mode()
method, which is discussed elsewhere.
cgiapp_postrun()
If implemented, this hook will be called after the run mode method has
returned its output, but before HTTP headers are generated. This will
give you an opportunity to modify the body and headers before they are
returned to the web browser.
A typical use for this hook is pipelining the output of a CGI-
Application through a series of "filter" processors. For example:
* You want to enclose the output of all your CGI-Applications in
an HTML table in a larger page.
* Your run modes return structured data (such as XML), which you
want to transform using a standard mechanism (such as XSLT).
* You want to post-process CGI-App output through another system,
such as HTML::Mason.
* You want to modify HTTP headers in a particular way across all
run modes, based on particular criteria.
The cgiapp_postrun() hook receives a reference to the output from your
run mode method, in addition to the CGI-App object. A typical
cgiapp_postrun() method might be implemented as follows:
sub cgiapp_postrun {
my $c = shift;
my $output_ref = shift;
# Enclose output HTML table
my $new_output = "<table border=1>";
$new_output .= "<tr><td> Hello, World! </td></tr>";
$new_output .= "<tr><td>". $$output_ref ."</td></tr>";
$new_output .= "</table>";
# Replace old output with new output
$$output_ref = $new_output;
}
Obviously, with access to the CGI-App object you have full access to
use all the methods normally available in a run mode. You could, for
example, use "load_tmpl()" to replace the static HTML in this example
with HTML::Template. You could change the HTTP headers (via
"header_add()" ). You could also use the objects properties to apply
changes only under certain circumstance, such as a in only certain run
modes, and when a "param()" is a particular value.
cgiapp_get_query()
my $q = $c->cgiapp_get_query;
Override this method to retrieve the query object if you wish to use a
different query interface instead of CGI.pm.
CGI.pm is only loaded to provided query object is only loaded if it
used on a given request.
If you can use an alternative to CGI.pm, it needs to have some
compatibility with the CGI.pm API. For normal use, just having a
compatible "param" method should be sufficient.
If use the "path_info" option to the mode_param() method, then we will
call the "path_info()" method on the query object.
If you use the "Dump" method in Titanium, we will call the "Dump" and
"escapeHTML" methods on the query object.
More Application Methods
You can skip this section if you are just getting started.
The following additional methods are inherited from Titanium, and are
available to be called by your application within your Application
Module. These functions are listed in alphabetical order.
error_mode()
$c->error_mode('my_error_rm');
If the runmode dies for whatever reason, "run() will" see if you have
set a value for "error_mode()". If you have, "run()" will call that
method as a run mode, passing $@ as the only parameter.
No "error_mode" is defined by default. The death of your
"error_mode()" run mode is not trapped, so you can also use it to die
in your own special way.
For a complete integrated logging solution, check out
CGI::Application::Plugin::LogDispatch.
header_add()
# add or replace the 'type' header
$c->header_add( -type => 'image/png' );
- or -
# add an additional cookie
$c->header_add(-cookie=>[$extra_cookie]);
The "header_add()" method is used to add one or more headers to the
outgoing response headers. The parameters will eventually be passed on
to the CGI.pm header() method, so refer to the CGI docs for exact usage
details.
Unlike calling "header_props()", "header_add()" will preserve any
existing headers. If a scalar value is passed to "header_add()" it will
replace the existing value for that key.
If an array reference is passed as a value to "header_add()", values in
that array ref will be appended to any existing values values for that
key. This is primarily useful for setting an additional cookie after
one has already been set.
header_props()
$c->header_props(-type=>'image/gif',-expires=>'+3d');
The "header_props()" method expects a hash of CGI.pm-compatible HTTP
header properties. These properties will be passed directly to
CGI.pm's "header()" or "redirect()" methods. Refer to CGI for exact
usage details.
Calling header_props any arguments will clobber any existing headers
that have previously set.
"header_props()" return a hash of all the headers that have currently
been set. It can be called with no arguments just to get the hash
current headers back.
To add additional headers later without clobbering the old ones, see
"header_add()".
IMPORTANT NOTE REGARDING HTTP HEADERS
It is through the "header_props()" and "header_add()" method that you
may modify the outgoing HTTP headers. This is necessary when you want
to set a cookie, set the mime type to something other than "text/html",
or perform a redirect. Understanding this relationship is important if
you wish to manipulate the HTTP header properly.
redirect()
return $c->redirect('http://www.example.com/');
Redirect to another URL.
forward()
return $c->forward('rm_name');
Pass control to another run mode and return its output. This is
equivalent to calling $self->$other_runmode, except that the internal
value of the current run mode is updated. This bookkeeping is important
to load_tmpl() when called with no arguments and some other plugins.
dbh()
sub cgiapp_init {
my $c = shift;
# use the same args as DBI->connect();
$c->dbh_config($data_source, $username, $auth, \%attr);
}
sub form_process {
my $c = shift;
my $dbh = $c->dbh;
}
Easy access to a DBI database handle. The database connection is not
created until the first call to "dbh()". See
CGI::Application::Plugin::DBH for more features and details.
session()
# in cgiapp_init()
$c->session_config(
CGI_SESSION_OPTIONS => [ "driver:PostgreSQL;serializer:Storable", $self->query, {Handle=>$dbh} ],
);
# in a run mode
my $ses = $c->session->param('foo');
Easy access to a CGI::Session object, so you can store user data
between requests. The session is not accessed or created until the
first call to session() in a given request. See
CGI::Application::Plugin::Session for more features and details.
cfg()
$c->cfg('root_uri');
Easy access to parameters loaded from a config file, which can be
stored in one of several formats, including YAML and Pure Perl. For
more features and details see CGI::Application::Plugin::ConfigAuto.
log()
$c->log->info('Information message');
$c->log->debug('Debug message');
Easy access to a Log::Dispatch logging object, allowing you to log to
different locations with different locations of severity. By adjusting
the logging level for your application, you make "debug" messages
appear or disappear from your logs without making pervasive code
changes. See CGI::Application::Plugin::LogDispatch for more features
and details.
check_rm()
my ($results, $err_page) = $c->check_rm('form_display','_form_profile');
return $err_page if $err_page;
Easy form validation with Data::FormValidator. If the validation fails,
we'll re-display the form for the user with their data pre-filled and
the errors highlighted. You'll have full control over the design of the
errors with HTML and CSS in your templates, although we provide some
intelligent defaults. See CGI::Application::Plugin::ValidateRM for
features and details.
fill_form()
# fill an HTML form with data in a hashref or from an object with with a param() method
my $filled_html = $self->fill_form($html, $data);
# ...or default to getting data from $self->query()
my $filled_html = $self->fill_form($html);
HTML::FillInForm is a useful when you want to fill in a web form with
default values from a database table. Like many CPAN modules, you can
use directly from CGI::Application without any special plugin. The
value of this plugin is that it defaults to finding values through
$self->query(). Besides that, it is just a bit of synatic sugar that
was mostly created work-around weaknesses in the HTML::FillInForm 1.x
interface, which were fixed with HTML::FillInForm 2.0 release. See
CGI::Application::Plugin::FillInForm for details.
error()
$c->error( title => '..', msg => '..' );
Provide quick error messages back to the user for exceptional cases.
You can provide your own custom designed template or use the default
one built-in. See CGI::Application::Plugin::ErrorPage.
stream_file()
$c->stream_file($file);
If your run mode is outputing an image or a spreadsheet instead of an
HTML page, you may want to stream the output. This method takes care of
the boring details of buffering, headers and MIME types. See
CGI::Application::Plugin::Stream for details.
prerun_mode()
$c->prerun_mode('new_run_mode');
The prerun_mode() method is an accessor/mutator which can be used
within your cgiapp_prerun() method to change the run mode which is
about to be executed. For example, consider:
# In WebApp.pm:
package WebApp;
use base 'Titanium';
sub cgiapp_prerun {
my $c = shift;
# Get the web user name, if any
my $q = $c->query();
my $user = $q->remote_user();
# Redirect to login, if necessary
unless ($user) {
$c->prerun_mode('login');
}
}
In this example, the web user will be forced into the "login" run mode
unless they have already logged in. The prerun_mode() method permits a
scalar text string to be set which overrides whatever the run mode
would otherwise be.
The prerun_mode() method should be used in cases where you want to use
Titanium's normal run mode switching facility, but you want to make
selective changes to the mode under specific conditions.
Note: The prerun_mode() method may ONLY be called in the context of a
cgiapp_prerun() method. Your application will die() if you call
prerun_mode() elsewhere, such as in setup() or a run mode method.
Dispatching Clean URIs to run modes
Modern web frameworks dispense with cruft in URIs, providing in clean
URIs instead. Instead of:
/cgi-bin/item.cgi?rm=view&id=15
A clean URI to describe the same resource might be:
/item/15/view
The process of mapping these URIs to run modes is called dispatching
and is handled by CGI::Application::Dispatch. Dispatching is not
required and is a layer you can fairly easily add to an application
later.
Offline website development
You can work on your Titanium project on your desktop or laptop without
installing a full-featured web-server like Apache. Instead, install
CGI::Application::Server from CPAN. After a few minutes of setup,
you'll have your own private application server up and running.
Automated Testing
There a couple of testing modules specifically made for Titanium.
Test::WWW::Mechanize::CGIApp allows functional testing of a
CGI::App-based project without starting a web server.
Test::WWW::Mechanize could be used to test the app through a real web
server.
Test::WWW::Selenium is similar, but uses Selenium for the testing,
meaning that a local web-browser would be used, allowing testing of
websites that contain JavaScript.
Direct testing is also easy. Titanium will normally print the output of
it's run modes directly to STDOUT. This can be surprised with an
enviroment variable, CGI_APP_RETURN_ONLY. For example:
$ENV{CGI_APP_RETURN_ONLY} = 1;
$output = $c->run;
like($output, qr/good/, "output is good");
Examples of this style can be seen in our own test suite.
PLUGINSTitanium has a plug-in architecture that is easy to use and easy to
develop new plug-ins for. Plugins made for CGI::Application are
directly compatible. The CGI::Application should be referenced for
those who wish to write plugins.
Select plugins are listed below. For a current complete list, please
consult CPAN:
http://search.cpan.org/search?m=dist&q=CGI%2DApplication%2DPlugin
· CGI::Application::Plugin::Apache - Use Apache::* modules without
interference
· CGI::Application::Plugin::AutoRunmode - Automatically register
runmodes
· CGI::Application::Plugin::CompressGzip - Add Gzip compression
· CGI::Application::Plugin::TT - Use Template::Toolkit as an
alternative to HTML::Template.
Consult each plug-in for the exact usage syntax.
COMMUNITY
Therese are primary resources available for those who wish to learn
more about Titanium and discuss it with others.
Wiki
This is a community built and maintained resource that anyone is
welcome to contribute to. It contains a number of articles of its own
and links to many other Titanium related pages. It is currently branded
as CGI::Application, but the code is the same.
http://www.cgi-app.org <http://www.cgi-app.org>
Support Mailing List
If you have any questions, comments, bug reports or feature
suggestions, post them to the support mailing list! To join the
mailing list, simply send a blank message to
"cgiapp-subscribe@lists.erlbaum.net".
IRC
You can also drop by "#cgiapp" on "irc.perl.org" with a good chance of
finding some people involved with the project there.
Source Code
This project is managed using the darcs source control system (
http://www.darcs.net/ ). The darcs archive is here:
http://mark.stosberg.com/darcs_hive/titanium
TODO
* I would like Titanium to be easier to install and get started with.
Rather than depending on the large CPAN dependency chain being
installed, I would like an option for users to download the full stack
of dependencies, so that you can just unpack a single file and go.
* I'd like a plugin to cope with the URI-encoding that Dreamweaver does
to templates that may just mean packing and releasing the following
code as a plug-in:
CGI::Application->add_callback('load_tmpl',sub {
my ($c, $ht_params, $tmpl_params, $tmpl_file) = @_;
require HTML::Template::Filter::URIdecode;
import HTML::Template::Filter::URIdecode 'ht_uri_decode';
# If you already have a filter defined, don't do anything.
# If you want to add more of your own filters later, be mindful
# about whether you add to this arrayref, or replace it.
unless ($ht_params->{filter}) {
$ht_params->{filter} = [\&ht_uri_decode]
}
});
SEE ALSO
· CGI::Application
MORE READING
If you're interested in finding out more about Titanium, the following
articles are available on Perl.com, providing context about the
underlying CGI::Application framework
Using CGI::Application
http://www.perl.com/pub/a/2001/06/05/cgi.html
Rapid Website Development with CGI::Application
http://www.perl.com/pub/a/2006/10/19/cgi_application.html
Thanks to O'Reilly for publishing these articles, and for the
incredible value they provide to the Perl community!
AUTHORS
Many.
Mark Stosberg, "mark@summersault.com" published the original Titanium
module, while many another contributed to CGI::Application and the
related plugins.
LICENSE
Copyright (C) 2008, Mark Stosberg.
This module is free software; you can redistribute it and/or modify it
under the terms of either:
a) the GNU General Public License as published by the Free Software
Foundation; either version 1, or (at your option) any later version,
or
b) the "Artistic License".
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See either the
GNU General Public License or the Artistic License for more details.
perl v5.14.1 2011-07-19 Titanium(3)
