WWW::Sitebase - Base class for Perl modules

WWW-Sitebase documentation Contained in the WWW-Sitebase distribution.

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NAME

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WWW::Sitebase - Base class for Perl modules

VERSION

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Version 0.9

SYNOPSIS

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(Derived from WWW::Myspace::MyBase 0.3)

This is a base class that can be used for all Perl modules. I could probably call it "Base" or somesuch, but that's a bit too presumptious for my taste, so I just included it here. You'll probably just use WWW::Sitebase::Navigator or WWW::Sitebase::Poster instead, which subclass WWW::Sitebase. WWW::Sitebase provides basic, standardized options parsing in several formats. It validates data using Params::Validate.

To use this in your new module, you simply subclass this module, add the "default_options" method to define your data, and write your methods.

 package WWW::MySite::MyModule;
 use WWW::Sitebase -Base;

 const default_options => {
 		happiness => 1, # Required
 		count => { default => 50 }, # Not required, defaults to 50
 	};

 field 'happiness';
 field 'count';

 sub mymethod {
 	if ( $self->happiness ) { print "I'm happy" }
 }




 People can then call your method with:
 $object = new WWW::MySite::MyModule( happiness => 5 );

 or

 $object = new WWW::MySite::MyModule( { happiness => 5 } );

See Params::Validate for more info on the format of, and available parsing stunts available in, default_options.

METHODS

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default_options

This method returns a hashref of the available options and their default values. The format is such that it can be passed to Params::Validate (and, well it is :).

You MUST override this method to return your default options. Basically, you just have to do this:

 sub default_options {

    $self->{default_options}={
 		option => { default => value },
 		option => { default => value },
    };

    return $self->{default_options};

 }

The approach above lets your subclasses add more options if they need to. it also sets the default_options parameter, and returns it so that you can call $self->default_options instead of $self->{default_options}.

positional_parameters

If you need to use positional paramteres, define a "positional_parameters" method that returns a reference to a list of the parameter names in order, like this:

 const positional_parameters => [ "username", "password" ];

If the first argument to the "new" method is not a recognized option, positional parameters will be used instead. So to have someone pass a browser object followed by a hashref of options, you could do:

 const positional_parameters => [ 'browser', 'options' ];

new

Initialize and return a new object.

 We accept the following formats:

 new - Just creates and returns the new object.
 new( $options_hashref )
 new( %options );
 new( @options ); - Each option passed is assigned in order to the keys
 					of the "DEFAULT_OPTIONS" hash.
 new( 'config_file' => "/path/to/file", 'config_file_format' => 'YAML' );
 	- File format can be "YAML" (see YAML.pm) or "CFG" (see Config::General).
 	- Defaults to "YAML" if not specified.

If you specify options and a config file, the config file will be read, and any options you explicitly passed will override the options read from the config file.

set_options

Allows you to set additional options. This is called by the "new" method to parse, validate, and set options into the object. You can call it yourself if you want to, either to set the options, or to change them later.

 # Set up the object
 $object->new( browser => $browser );

 # Read in a config file later.
 $object->set_options( config_file => $user_config );

This also lets you override options you supply directly with, say, a user-supplied config file. Otherwise, the options passed to "new" would override the config file.

get_options

General accessor method for all options. Takes a list of options and returns their values.

If called with one option, returns just the value. If called with more than one option, returns a list of option => value pairs (not necessarily in the order of your original list). If called with no arguments, returns a list of all options and their values (as option => value pairs).

This is basically a "catch all" accessor method that allows you to be lazy ad not create accessors for your options.

parse_options

This method is called by set_options to determine the format of the options passed and return a hash of option=>value pairs. If needed, you can call it yourself using the same formats described in "new" above.

 $object->new;
 $object->parse_options( 'username' => $username,
 	'config_file' => "/path/to/file" );

read_config_file

This method is called by parse_options. If a "config_file" argument is passed, this method is used to read options from it. Currently supports CFG and YAML formats.

save( filename )

Saves the object to the file specified by "filename". Saves every field specified in the default_options and positional_parameters methods.

_nosave( fieldname )

Override this method in your base class if there are fields you don't want the save command to save. Otherwise, all fields specified in your default_options and postitional_parameters will be saved.

_nosave is passed a field name. Return 1 if you don't want it saved. Return 0 if you want it saved. The stub method just returns 0.

 Sample _nosave method:
 sub _nosave {

    my ( $key ) = @_;

    # List only fields you don't want saved
    my %fields = ( fieldname => 1, fieldname2 => 1 );

    if ( $key && ( $fields{"$key"} ) ) { return 1 } else { return 0 }

 }

load( filename )

Loads a message in YAML format (i.e. as saved by the save method) from the file specified by filename.

AUTHOR

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Grant Grueninger, <grantg at cpan.org>

BUGS

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Please report any bugs or feature requests to bug-www-bebo at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=WWW-Bebo. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

NOTES

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You currently have to both specify the options in default_options and create accessor methods for those you want accessor methods for (i.e. all of them). This should be made less redundant.

We probably want to include cache_dir and possibile cache_file methods here.

TO DO

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SUPPORT

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You can find documentation for this module with the perldoc command.

    perldoc WWW::Bebo::Base

You can also look for information at:

* AnnoCPAN: Annotated CPAN documentation

http://annocpan.org/dist/WWW-Bebo

* CPAN Ratings

http://cpanratings.perl.org/d/WWW-Bebo

* RT: CPAN's request tracker

http://rt.cpan.org/NoAuth/Bugs.html?Dist=WWW-Bebo

* Search CPAN

http://search.cpan.org/dist/WWW-Bebo

ACKNOWLEDGEMENTS

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COPYRIGHT & LICENSE

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Copyright 2005 Grant Grueninger, all rights reserved.

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

WWW-Sitebase documentation Contained in the WWW-Sitebase distribution. 
# $Id: Sitebase.pm,v 1.10 2009/08/10 09:28:39 grant Exp $

package WWW::Sitebase;

use Spiffy -Base;
use Carp;
use Params::Validate;
use Config::General;
use YAML qw'LoadFile DumpFile';


our $VERSION = '0.9';


#
######################################################################
# Setup

######################################################################
# Libraries we use

######################################################################
# new


stub 'default_options';


stub 'positional_parameters';


sub new() {

	# Set up the basic object
    my $proto = shift;
    my $class = ref($proto) || $proto;
    my $self  = {};

    bless( $self, $class );

	# Unless they passed some options, we're done.
	return $self unless ( @_ );
	
	# Set the options they passed.
	$self->set_options( @_ );

	# Done
	return $self;

}


sub set_options {

	# Figure out the paramter format and return a hash of option=>value pairs
	my %options = $self->parse_options( @_ );

	# Validate the options
	my @options = ();
	foreach my $key ( keys %options ) {
		push ( @options, $key, $options{$key} );
	}

	%options = validate( @options, $self->default_options );

	# Copy them into $self
	foreach my $key ( keys( %options ) ) {
		$self->{"$key"} = $options{"$key"}
	}
	
}


sub get_options {

	my ( @options ) = @_;

	# If no options were specified, return them all
	unless ( @options ) {
		@options = keys( %{ $self->default_options } );
	}

	# If there's only one value requested, return just it
	return $self->{$options[0]} if ( @options == 1 );
	
	# Otherwise return a hash of option => value pairs.
	my %ret_options = ();
	
	foreach my $option ( @options ) {
		if ( $self->{ $option } ) {
			$ret_options{ $option } = $self->{ $option };
	    } else {
			croak "Invalid option passed to get_options";
		}
	}
	
	return ( %ret_options );

}


sub parse_options {

	my %options = ();

	# figure out the format
	# - new( $options_hashref )
    if ( ( @_ == 1 ) && ( ref $_[0] eq 'HASH') ) {
		%options = %{ $_[0] };
	# - new( %options )
	#   If more than 1 argument, and an even number of arguments, and
	#   the first argument is one of our known options.
	} elsif ( ( @_ > 1 ) && ( @_ % 2 == 0 ) &&
		( defined( $self->default_options->{ "$_[0]" } ) ) ) {
		%options = ( @_ );
	# - new( @options )
	#   We just assign them in order.
	} else {
		foreach my $option ( @{ $self->positional_parameters } ) {
			$options{"$option"} = shift;
		}
	}
	
	# If they passed a config file, read it
	if ( exists $options{'config_file'} ) {
		%options = $self->read_config_file( %options );
	}
	
	return %options;

}


sub read_config_file {

	my ( %options ) = @_;
	
	my %config;

	# XXX CFG reads into a hash, YAML reads into a hashref.
	# This is a bit unstable, but YAML's file looks weird if you
	# just dump a hash to it, and hashrefs are better anyway.
	if ( ( defined $options{'config_file_format'} ) &&
		( $options{'config_file_format'} eq "CFG" ) ) {
		# Read CFG-file format
		my $conf = new Config::General( $options{'config_file'} );
		%config = $conf->getall;
	} else {
		# Default to YAML format
		my $config = LoadFile( $options{'config_file'} );
		%config = %{ $config };
	}
	
	# Copy the config file into the options hashref.
	# Existing params override the config file
	foreach my $key ( keys %config ) {
		unless ( exists $options{"$key"} ) {
			$options{"$key"} = $config{"$key"};
		}
	}

	return %options;
		
}


sub save {

    my $filename = shift;
	my $data = {};

	# For each field listed as persistent, store it in the
	# hash of data that's going to be saved.
	foreach my $key ( ( keys( %{ $self->default_options } ),
			@{ $self->positional_parameters } ) ) {
		unless ( $self->_nosave( $key ) ) {
			# IMPORTANT: Only save what's defined or we'll
			# break defaults.
			if ( exists $self->{$key} ) {
				${$data}{$key} = $self->{$key}
			}
		}
	}

	DumpFile( $filename, $data );

}


sub _nosave { return 0 }


sub load {

	my ( $file ) = @_;
	my $data = {};
	
	( $data ) = LoadFile( $file );

	# For security we only loop through fields we know are
	# persistent. If there's a stored value for that field, we
	# load it in.
	foreach my $key ( ( keys( %{ $self->default_options } ),
			@{ $self->positional_parameters } ) ) {
		if ( exists ${$data}{$key} ) {
			$self->{$key} = ${$data}{$key}
		}
	}
	
}


1; # End of WWW::Bebo::Base