NAME
CGI::Application::Plugin::Config::General - Add Config::General Support
to CGI::Application
VERSION
Version 0.03
SYNOPSIS
Simple Access to Configuration
In your CGI::Application-based module:
use base 'CGI::Application';
use CGI::Application::Plugin::Config::General;
sub cgiapp_init {
my $self = shift;
# Set config file and other options
$self->conf->init(
-ConfigFile => 'app.conf',
);
}
sub my_run_mode {
my $self = shift;
# get entire configuration
my %conf = $self->conf->getall;
# get entire configuration (as a reference)
my $conf = $self->conf->getall;
# get single config parameter
my $value = $self->conf->param('some_value');
# get underlying Config::General object
my $obj = $self->conf->obj;
}
Configuration Based on URL or Module
You can match a configuration section to the request URL, or to the
module name. For instance, given the following configuration file:
admin_area = 0
admin_area = 1
title = Admin Area
title = Feedback Form
The configuration will depend on how the script is called:
# URL: /cgi-bin/feedback.cgi?rm=add
# Module: MyApp::Feedback
print $self->conf->param('admin_area'); # 0
print $self->conf->param('title'); # 'Feedback Form'
# URL: /cgi-bin/admin/users.cgi
# Module: MyApp::Admin::Users
print $self->conf->param('admin_area'); # 1
print $self->conf->param('title'); # 'Admin Area'
Matching Configuration based on a Virtual Host
This module can also pick a configuration section based on the current
virtual-host:
# httpd.conf
SetEnv SITE_NAME REDSITE
# in app.conf
background = blue
foreground = white
background = red
foreground = pink
background = darkgreen
foreground = lightgreen
DESCRIPTION
This module allows you to easily access configuration data stored in
"Config::General" (i.e. Apache-style) config files.
You can also automatically match configuration sections to the request
URL, or to the module name. This is similar to how Apache dynamically
selects a configuration by matching the request URL to e.g. ""
and "" sections.
You can also select configuration sections based on Virtual Host or by a
variable you set in an ".htaccess" file. This allows you to share a
single application between many virtual hosts, each with its own unique
configuration. This could be useful, for instance, in providing multiple
themes for a single application.
Simple access to Configuration
This module provides a "conf" method to your "CGI::Application" object.
First, you initialize the configuration system (typically in your
"cgiapp_init" method):
$self->conf->init(
-ConfigFile => 'app.conf',
);
The configuration file is parsed at this point and is available from
this point on.
Then, within your run-modes you can retrieve configuration data:
# get entire configuration
my %conf = $self->conf->getall;
my $value = $conf{'some_value'};
# get entire configuration (as a reference)
my $conf = $self->conf->getall;
my $value = $conf{'some_value'};
# get single config parameter
my $value = $self->conf->param('some_value');
Multiple named Configurations
You can use more than one configuration by providing a name to the
"conf" method:
$self->conf('database')->init(
-ConfigFile => 'app.conf',
);
$self->conf('application')->init(
-ConfigFile => 'app.conf',
);
...
my %db_config = $self->conf('database')->getall;
my %app_config = $self->conf('application')->getall;
Configuration based on URL or Module
Within your configuration file, you can provide different configurations
depending on the current URL, or on the package name of your
application.
Matches against the "SITE_NAME" environment variable, using an
*exact* match.
# httpd.conf
SetEnv SITE_NAME REDSITE
# in app.conf
background = blue
foreground = white
background = red
foreground = pink
background = darkgreen
foreground = lightgreen
You can use name your sections something other than "", and
you can use a different environment variable than "SITE_NAME". See
"Notes on Site Matching", below.
Matches against the "SITE_NAME" environment variable using a regular
expression.
# httpd.conf
SetEnv SITE_NAME REDSITE
# in app.conf
background = blue
foreground = white
background = red
foreground = pink
background = darkgreen
foreground = lightgreen
You can use name your sections something other than "", and
you can use a different environment variable than "SITE_NAME". See
"Notes on Site Matching", below.
Matches the Package name of your application module, for instance:
...
The match is performed hierachically, like a filesystem path, except
using "::" as a delimiter, instead of "/". The match is tied to the
beginning of the package name, just like absolute paths. For
instance, given the section:
...
the packages "Admin" and "Admin::Users" would match, but the
packages "Foo::Admin" and "Administrative" would not.
For instance, given the section:
...
Matches the package name of your application module, using a regular
expression. The expression is not tied to the start of the string.
For instance, given the section:
...
The following packages would all match: "Admin", "Admin::Users",
"Foo::Admin", "Administrative".
Matches hierarchically against the request URI, including the path
and the "PATH_INFO" components, but *excluding* the scheme, host,
port and query string.
So, for instance with the following URL:
http://bookstore.example.com/cgi-bin/category.cgi/fiction/?rm=list
The Location would be:
/cgi-bin/category.cgi/fiction/
This is obtained by calling the "url" method of the query object
(either "CGI" or "CGI::Simple"):
$path = $webapp->query->url('-absolute' => 1, '-path_info' => 1);
Matches against the request URI, using a regular expression.
Section Merge Order
The sections are matched in the following order:
Site: and
Package Name: and
URL: and
When there is more than one matching section at the same level of
priority (e.g. two "" sections, or both an "" and an
"" section), then the sections are merged in the order of
shortest match first.
Values in sections matched later override the values in sections matched
earlier.
The idea is that the longer matches are more specific and should have
priority.
Section Nesting
The sections can be nested inside each other. For instance:
admin_books = 1
admin_records = 1
By default, the sections can be nested up to two levels deep. You can
change this by setting the "-NestingDepth" parameter to "init".
Merging Configuration Values into your Template
You can easily pass values from your configuration files directly to
your templates. This allows you to associate HTML titles with URLs, or
keep text like copyright notices in your config file instead of your
templates:
copyright_notice = Copyright (C) 1492 Christopher Columbus
title = "Manifest Destiny, Inc. - About Us"
title = "Manifest Destiny, Inc. - Contact Us"
If you do this, you should consider keeping your database passwords and
other sensitive data in a separate configuration file, in order to avoid
accidentally leaking these data into your web pages.
If you use "HTML::Template", you use the associate method when you load
the template:
$self->load_template(
'template.tmpl',
'associate' => $self->conf,
);
If you use "Template::Toolkit" (via the "CGI::Application::Plugin::TT"
module), you can accomplish the same thing by providing a custom
tt_pre_process method:
sub tt_pre_process {
my $self = shift;
my $template = shift;
my $template_params = shift;
my $config = $self->conf->getall
foreach (keys %$config) {
unless (exists $template_params->{$_}) {
$template_params->{$_} = $config->{$_};
}
}
}
METHODS
init
Initializes the plugin. The only required parameter is a config file:
$self->conf->init(
-ConfigFile => 'app.conf',
);
The other paramters are described below:
-ConfigFile
The path to the configuration file to be parsed.
-Options
Any additional "Config::General::Match" options. See the
documentation to "Config::General" and "Config::General::Match" for
more details.
-CacheConfigFiles
Whether or not to cache configuration files. Enabled, by default.
This option is only really useful in a persistent environment such
as "mod_perl". See "Config File Caching", "ADVANCED USAGE", below.
-StatConfig
If config file caching is enabled, this option controls how often
the config files are checked to see if they have changed. The
default is 60 seconds. This option is only really useful in a
persistent environment such as "mod_perl". See "Config File
Caching", "ADVANCED USAGE", below.
-SiteSectionName
Change the name of the "" section to something else. For
instance, to use sections named "", use:
-SiteSectionName => 'VirtualHost'
-SiteVar
Change the name of the "SITE_NAME" environment variable used to
match against "" sections. For instance To change this name to
"HTTP_HOST", use:
-SiteVar => 'HTTP_HOST',
-NestingDepth
The number of levels deep that sections can be nested. The default
is two levels deep.
See "Section Nesting", above.
You can initialize the plugin from within your instance CGI script:
my $app = WebApp->new();
$app->conf->init(-ConfigFile => '../../config/app.conf');
$app->run();
Or you can do so from within your "cgiapp_init" method within the
application:
sub cgiapp_init {
my $self = shift;
$self->conf->init(
-ConfigFile => "$ENV{DOCUMENT_ROOT}/../config/app.conf"
);
}
getall
Gets the entire configuration as a hash or hashref:
my %config = $self->conf->getall; # as hash
my $config = $self->conf->getall; # as hashref
Note that the following two method calls will return different results:
my $config = $self->conf->getall; # parsed config
my $config = $self->conf->obj->getall; # raw config
In the first case, the matching based on URI, Module, etc. has already
been performed. In the second case, you are accessing the raw config
with all of the "", "", etc. sections intact.
param
Allows you to retrieve individual values from the configuration.
It behvaves like the method in other classes, such as "CGI",
"CGI::Application" and "HTML::Template":
$value = $self->conf->param('some_key');
@all_keys = $self->conf->param();
obj
Provides access to the underlying Config::General::Match> object.
You can access the raw unparsed configuration data by calling
my $config = $self->conf->obj->getall; # raw config
See the note under "getall", above.
In future versions of this module, certain caching strategies may
prevent you from accessing the underlying Config::General::Match object.
get_current_config ($name)
This is a class method which returns the current configuration object.
my $conf = CGI::Application::Plugin::Config::General->get_current_config;
print $conf->{'title'};
my %db_conf = CGI::Application::Plugin::Config::General->get_current_config('db');
print $db_conf{'username'};
This method is most useful in situations where you don't have access to
the "CGI::Application" object, such within a "Class::DBI" class. See
"Access to Configuration information from another Class" for an example.
Note that "get_current_config" returns the configuration hash (or
hashref) directly. It is the equivalent of calling
"$self->conf->getall".
ADVANCED USAGE
Usage in a Persistent Environment such as mod_perl
The following sections describe some notes about running this module
under mod_perl:
Config File Caching
By default each config file is read only once when the conf object is
first initialized. Thereafter, on each init, the cached config is used.
If enough time has passed (sixty seconds by default) the config file is
checked to see if it has changed. If it has changed, then the file is
reread.
If you are using "Config::General" version 2.28 or greater, then you can
safely use the "include" feature of "Config::General" and all included
files will be checked for changes along with the main file.
To disable caching of config files pass a false value to the
"-CacheConfigFiles" parameter to init, e.g:
$self->conf->init(
-ConfigFile => 'app.conf',
-CacheConfigFiles => 0,
);
To change how often config files are checked for changes, change the
value of the "-StatConfig" paramter to init, e.g.:
$self->conf->init(
-ConfigFile => 'app.conf',
-StatConfig => 1, # check the config file every second
);
PerlSetVar instead of SetEnv
For a (slight) performance improvement, you can use "PerlSetVar" instead
of "SetEnv" within a " < >:
# httpd.conf
PerlSetVar SITE_NAME REDSITE
Notes on Site Matching
Renaming "" or "SITE_NAME"
Normally, the environment variable "SITE_NAME" is matched to ""
and "" sections.
You can change these with the "-SiteSectionName" and "-SiteVar"
parameters to "init":
$self->conf->init(
-ConfigFile => 'app.conf',
-SiteSectionName => 'Host',
-SiteVar => 'MY_HOST',
);
This will match the environment variable "MY_HOST" to the sections
"" and "".
Setting "SITE_NAME" from an ".htaccess" file or the CGI script
Since "SITE_NAME" is just an environment variable, you can set it
anywhere you can set environment variables. For instance in an
".htaccess" file:
# .htaccess
SetEnv SITE_NAME bookshop
Or even the calling CGI script:
#!/usr/bin/perl
use MySite::WebApp;
$ENV{'SITE_NAME'} = 'recordshop';
my $app = MySite::WebApp->new();
$app->run();
Access to Configuration information from another Class
You can also get at the current configuration settings from a completely
unrelated Perl module. This can be useful for instance if you need to
configure a set of "Class::DBI" classes, and you want them to be able to
pick up their configuration on their own. For instance:
# app.conf
connect_string = dbi:Pg:dbname=example
username = test
password = test
RaiseError = 1
AutoCommit = 1
# In your Class::DBI subclass
package My::Class::DBI::Base;
use base 'Class::DBI';
sub db_Main {
my $conf = CGI::Application::Plugin::Config::General->get_current_config;
my $dsn = $conf->{'database'}{'connect_string'};
my $user = $conf->{'database'}{'username'};
my $pass = $conf->{'database'}{'password'};
my $opts = $conf->{'database'}{'options'};
return DBI->connect_cached($dsn, $user, $pass, $opts);
}
For this example to work, you need to make sure you call
"$self-"conf->init> before you access the database through any of your
"Class::DBI" objects.
Note that "get_current_config" returns the configuration hash (or
hashref) directly. is the equivalent of calling "$self->conf->getall".
Changing Parsing Behaviour Using Custom "-MatchSections"
Internally, this module uses "Config::General" and
"Config::General::Match" to parse its config files. If you want to
change the parsing behaviour, you can pass your own "-MatchSections"
list to "init". For instance, if you want to allow only sections named
"", with no nesting, and have these matched exactly to the complete
request path, you could do the following:
# app.conf
admin_area = 0
user_area = 0
admin_area = 1
user_area = 1
# in your cgiapp_init:
$self->conf->init(
-ConfigFile => 'app.conf',
-NestingDepth => 1,
-Options => {
-MatchSections => [
{
-Name => 'URL',
-MatchType => 'exact',
-MergePriority => 0,
-SectionType => 'path',
},
]
}
);
For reference, here is the default "-MatchSections":
-MatchSections => [
{
-Name => 'Site', # overridden by -SiteSectionName
-MatchType => 'exact',
-MergePriority => 0,
-SectionType => 'env',
},
{
-Name => 'AppMatch',
-MatchType => 'regex',
-SectionType => 'module',
-MergePriority => 1,
},
{
-Name => 'App',
-MatchType => 'path',
-PathPathSeparator => '::',
-SectionType => 'module',
-MergePriority => 1,
},
{
-Name => 'LocationMatch',
-MatchType => 'regex',
-SectionType => 'path',
-MergePriority => 3,
},
{
-Name => 'Location',
-MatchType => 'path',
-SectionType => 'path',
-MergePriority => 3,
},
],
For each section, the "-SectionType" param indicates what runtime
variable the section will be matched against. Here are the allowed
values
env: matched to the environment variable SITE_NAME (overridden by -SiteNameVar)
module: name of the Perl Module handling this request (e.g. MyApp::Users)
path: path of the request, including path_info (e.g. /cgi-bin/myapp/users.cgi/some/path)
You can use the above "-SectionType" values in your own custom
"-MatchSection".
AUTHOR
Michael Graham, ""
BUGS
Please report any bugs or feature requests to
"bug-cgi-application-plugin-config-general@rt.cpan.org", or through the
web interface at . I will be notified, and then
you'll automatically be notified of progress on your bug as I make
changes.
ACKNOWLEDGEMENTS
This module would not be possible without Thomas Linden's excellent
"Config::General" module.
Thanks to the excellent examples provided by the other
"CGI::Application" plugin authors: Mark Stosberg, Michael Peters, Cees
Hek and others.
SEE ALSO
CGI::Application
Config::General
Config::General::Match
CGI::Application::Plugin::Config::Simple
CGI::Application::Plugin::ConfigAuto
COPYRIGHT & LICENSE
Copyright 2005 Michael Graham, All Rights Reserved.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.