App::Info::Request(3p)

NAME
App::Info::Request - App::Info event handler request object

SYNOPSIS
  # In an App::Info::Handler subclass:
  sub handler {
      my ($self, $req) = @_;
      print "Event Type:  ", $req->type;
      print "Message:     ", $req->message;
      print "Error:       ", $req->error;
      print "Value:       ", $req->value;
  }

DESCRIPTION
Objects of this class are passed to the handler() method of App::Info event handlers. Generally, this class will be of most interest to App::Info::Handler subclass implementers.

The event triggering methods in App::Info each construct a new App::Info::Request object and initialize it with their arguments. The App::Info::Request object is then the sole argument passed to the handler() method of any and all App::Info::Handler objects in the event handling chain. Thus, if you'd like to create your own App::Info event handler, this is the object you need to be familiar with. Consult the App::Info::Handler documentation for details on creating custom event handlers.

Each of the App::Info event triggering methods constructs an App::Info::Request object with different attribute values. Be sure to consult the documentation for the event triggering methods in App::Info, where the values assigned to the App::Info::Request object are documented. Then, in your event handler subclass, check the value returned by the type() method to determine what type of event request you're handling to handle the request appropriately.

INTERFACE
The following sections document the App::Info::Request interface.

  Constructor
new

  my $req = App::Info::Request->new(%params);

This method is used internally by App::Info to construct new App::Info::Request objects to pass to event handler objects. Generally, you won't need to use it, other than perhaps for testing custom App::Info::Handler classes.

The parameters to new() are passed as a hash of named parameters that correspond to their like-named methods. The supported parameters are:

type
message
error
value
callback

See the object methods documentation below for details on these object attributes.

  Object Methods
key

  my $key = $req->key;

Returns the key stored in the App::Info::Request object. The key is used by the App::Info subclass to uniquely identify the information it is harvesting, such as the path to an executable. It might be used by request handlers, for example, to see if an option was passed on the command-line.

message

  my $message = $req->message;

Returns the message stored in the App::Info::Request object. The message is typically informational, or an error message, or a prompt message.

error

  my $error = $req->error;

Returns any error message associated with the App::Info::Request object. The error message is typically there to display for users when callback() returns false.

type

  my $type = $req->type;

Returns a string representing the type of event that triggered this request. The types are the same as the event triggering methods defined in App::Info. As of this writing, the supported types are:

info
error
unknown
confirm

Be sure to consult the App::Info documentation for more details on the event types.

callback

  if ($req->callback($value)) {
      print "Value '$value' is valid.\n";
  } else {
      print "Value '$value' is not valid.\n";
  }

Executes the callback anonymous subroutine supplied by the App::Info concrete base class that triggered the event. If the callback returns false, then $value is invalid. If the callback returns true, then $value is valid and can be assigned via the value() method.

Note that the value() method itself calls callback() if it was passed a value to assign. See its documentation below for more information.

value

  my $value = $req->value;
  if ($req->value($value)) {
      print "Value '$value' successfully assigned.\n";
  } else {
      print "Value '$value' not successfully assigned.\n";
  }

When called without an argument, value() simply returns the value currently stored by the App::Info::Request object. Typically, the value is the default value for a confirm event, or a value assigned to an unknown event.

When passed an argument, value() attempts to store the the argument as a new value. However, value() calls callback() on the new value, and if callback() returns false, then value() returns false and does not store the new value. If callback() returns true, on the other hand, then value() goes ahead and stores the new value and returns true.

SUPPORT
This module is stored in an open GitHub repository <http://github.com/theory/app-info/>. Feel free to fork and contribute!

Please file bug reports via GitHub Issues <http://github.com/theory/app-info/issues/> or by sending mail to bug-App-Info@rt.cpan.org <mailto:bug-App-Info@rt.cpan.org>.

AUTHOR
David E. Wheeler <david@justatheory.com>

SEE ALSO
App::Info documents the event triggering methods and how they construct App::Info::Request objects to pass to event handlers.

App::Info::Handler: documents how to create custom event handlers, which must make use of the App::Info::Request object passed to their handler() object methods.

The following classes subclass App::Info::Handler, and thus offer good exemplars for using App::Info::Request objects when handling events.

App::Info::Handler::Carp
App::Info::Handler::Print
App::Info::Handler::Prompt

COPYRIGHT AND LICENSE
Copyright (c) 2002-2011, David E. Wheeler. Some Rights Reserved.

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