CGI::Application::Plugin::Config::Simple(3) Add Config::Simple support to CGI::Application

SYNOPSIS

in your CGI::Application based module


use CGI::Application::Plugin::Config::Simple;
sub cgiapp_init {
my $self = shift;
#set my config file
$self->config_file('myapp.conf');
#
#do other stuff
#
}
#later on in a run mode
sub run_mode1 {
my $self = shift;
#just get a single parameter from my config file
my $value = $self->config_param('my_param');
#get a parameter in a block (if using ini style files)
$value = $self->config_param('my_block.my_param');
#the entire config hash reference
my $config_vars = $self->config_param();
#get my Config::Simple object for direct access
my $config = $self->config;
}

DESCRIPTION

This module acts as a plugin for Config::Simple to be easily used inside of a CGI::Application module. It does not provide every method available from Config::Simple but rather easy access to your configuration variables. It does however provide direct access to the underlying Config::General object created if you want to use it's full power.

The module tries to make the getting and setting of configuration variables as easy as possible. Only three methods are exported into your CGI::Application module and they are described below.

Before I wrote this module sometimes I would put my code that read in the configuration file into the cgiapp_init() or cgiapp_prerun() methods but then if I had a run mode that didn't need those config variables it was run anyway. This module helps to solve this is. The Config::Simple object is not created (and the config file is not read and parsed) until after your first call to config() or config_param() to either retrieve/set values, or get the Config::Simple object. This lazy loading idea came from Cees Hek's CGI::Application::Plugin::Session module.

METHODS

config_param()

This method acts as an accessor/mutator for configuration variables coming from the configuration file.

This method will behave in three different ways depending on how many parameters it is passed. If 0 parameters are passed then the entire config structure will be returned as a hash ref. If 1 parameters is passed then the value of that parameter in the config file will be returned. If more than 1 parameter is passed then it will treat them as name value pairs and will set the parameters in the config file accordingly. In this case, if we successfully set the parameters then a true value will be returned. 

        #get the complete config hash
        my $config_hash = $self->config_param();
        #just get one config value
        my $value = $self->config_param($parameter);
        #set multiple config values
        my $success = $self->config_param(param1 => $value1, param2 => $value2);

This method uses Config::Simple so if you are using ini-files then you can set the values of variables inside blocks as well using the '.' notation. See Config::Simple;

You must set the name of the configuration file either using the config_file() method or the CGIAPP_CONFIG_FILE environment variable before calling this method or it will 'die'.

config()

This method will return the underlying Config::Simple object for more direct use by your application. You must set the name of the configuration file either using the config_file() method or the CGIAPP_CONFIG_FILE environment variable before calling this method or it will 'die'. 

        my $conf = $self->config();

config_file([$file_name])

This method acts as an accessor/mutator to either get the name of the current config file or to change/initialize it. This method must be called to initialize the name of the config file before any call can be made to either config() or config_param() unless the 'CGIAPP_CONFIG_FILE' environment variable has been set. If this environment variable is set it will be used as the initial value of the config file. This is useful if we are running in a mod_perl environment when can use a statement like this in your httpd.conf file: 

        PerlSetEnv  CGIAPP_CONFIG_FILE  /path/to/my/conf

It is typical to set the name of the config file in the cgiapp_init() phase of your application.

If a value is passed as a parameter then the config file with that name is used. It will always return the name of the current config file. 

        #get the value of the CGIAPP_CONFIG_FILE environment variable (if there is one)
        #since we haven't set the config file's name with config_file() yet.
        my $file_name = $self->config_file();
                                                                                                                                             
        #set the config file's name
        $self->config_file('myapp.conf');
                                                                                                                                             
        #get the name of the config file
        $file_name = $self->config_file();

CAVEATS

The CGI::Application object is implemented as a hash and we store the variables used by this module's methods inside of it as a hash named __CONFIG_SIMPLE. If you use any other CGI::Application plugins there would be problems if they also used $self->{__CONFIG_SIMPLE} but in practice this should never actually happen.

AUTHOR

Michael Peters <[email protected]>

Thanks to Plus Three, LP (http://www.plusthree.com) for sponsoring my work on this module

LICENSE

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

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