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Workflow::Validator.3pm

NAME

Workflow::Validator - Ensure data are valid

VERSION

This documentation describes version 1.05 of this package

SYNOPSIS

  # First declare the validator...
  <validator name="DateValidator"
             class="MyApp::Validator::Date">
    <param name="date_format" value="%Y-%m-%d %h:%m"/>
  </validator>
  
  # Then associate the validator with runtime data from the context...
  <action name="MyAction">
     <validator name="DateValidator">
        <arg>$due_date</arg>
     </validator>
  </action>
  
  # TODO: You can also inintialize and instantiate in one step if you
  # don't need to centralize or reuse (does this work?)
  
  <action name="MyAction">
     <validator class="MyApp::Validator::Date">
        <param name="date_format" value="%Y-%m-%d %h:%m"/>
        <arg>$due_date</arg>
     </validator>
  </action>
  
  # Then implement the logic
  
  package MyApp::Validator::Date;
  
  use strict;
  use base qw( Workflow::Validator );
  use DateTime::Format::Strptime;
  use Workflow::Exception qw( configuration_error );
  
  __PACKAGE__->mk_accessors( 'formatter' );
  
  sub _init {
      my ( $self, $params ) = @_;
      unless ( $params->{date_format} ) {
          configuration_error
              "You must define a value for 'date_format' in ",
              "declaration of validator ", $self->name;
      }
      if ( ref $params->{date_format} ) {
          configuration_error
              "The value for 'date_format' must be a simple scalar in ",
              "declaration of validator ", $self->name;
      }
      my $formatter = DateTime::Format::Strptime->new(
                               pattern => $params->{date_format},
                               on_error => 'undef' );
      $self->formatter( $formatter );
  }
  
  sub validate {
      my ( $self, $wf, $date_string ) = @_;
      my $fmt = $self->formatter;
      my $date_object = $fmt->parse_datetime( $date_string );
      unless ( $date_object ) {
          validation_error
              "Date '$date_string' does not match pattern '", $fmt->pattern, "' ",
              "due to error '", $fmt->errstr, "'";
      }
  }
 
 

DESCRIPTION

Validators specified by 'validator_name' are looked up in the Workflow::Factory which reads a separate configuration and generates validators. (Generally all validators should be declared, but it is not required.)

Validators are objects with a single public method, 'validate()' that take as arguments a workflow object and a list of parameters. The parameters are filled in by the workflow engine according to the instantiation declaration in the Action.

The idea behind a validator is that it validates data but does not care where it comes from.

SUBCLASSING

Strategy

Methods

init( \%params )

Called when the validator is first initialized. If you do not have sufficient information in "\%params" you should throw an exception.

_init

This is a dummy method, please see ``init''.

validate( $workflow, $data )

Determine whether your $data is true or false. If necessary you can get the application context information from the $workflow object.

COPYRIGHT

Copyright (c) 2003-2004 Chris Winters. All rights reserved.

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

AUTHORS

Chris Winters <chris@cwinters.com>