For Average Users¶

Simply load the config plugin before other modules that might use it:

  use CGI::Application::Plugin::ConfigAuto;
  use CGI::Application::Plugin::Session;

For Configuration plugin authors¶

Configuration plugin authors only need to follow the standards documented below.

For other plugin authors who wish to rely on the standard¶

Plugin authors who want to possibly use this standard can do so by simply using this module:

  package CGI::Application::Plugin::Session;
  use CGI::Application::Standard::Config;

If a standards complaint config module hasn't already been loaded a stub for config() will be added which will safely return "undef".

Example use by another plugin

Here code first tries to get configuration details first from a config file, then from options passed to a plugin-specific config method, and finally applies defaults if no configuration options are found.

 my $session_options = $self->config('Session_options')
                                      || $self->session_config()
                                      || $self->session_defaults;

$self->std_config¶

This method should be exported by default to simply declare that you meet the standard report which version of the standard you meet. This simple implementation is recommended:

 sub std_config { return 1; }

$self->config¶

The intended use is to load to read-only configuration details once from a config file at start up time.

This service is provided by plugins (list below). They must support at at least this syntax:

 my $value = $self->config('key');

By default, "config()" simply returns undef, making it safe for other plugins to directly to check if "$self-"config('key')> returns the value it needs.

config() must be exported by default.

For applications that need little configuration, config() is not necessary-- using "PARAMS" in an instance script should suffice.

Also, the "param()" is the appropriate method to use to set a configuration value at run time.

Configuration plugins that provide at least this basic API include:

CGI::Application::Plugin::ConfigAuto.

Standard config variables

Users are encouraged to use these standard config variable names, to ease compatibility between plugins:

 ROOT_URI - A URI corresponding to the project root (http://foo.com/proj )
 ROOT_DIR - a file system path to the same location ( /home/joe/www/proj )

All-caps are used to denote that config variables are essentially global constants.

Why URI and not URL? The wikipedia explains:

  The contemporary point of view among the working group that oversees URIs is
  that the terms URL and URN are context-dependent aspects of URI and rarely
  need to be distinguished. Furthermore, the term URL is increasingly becoming
  obsolete, as it is rarely necessary to differentiate between URLs and URIs,
  in general.