Brock Wilcox

NAME

CGI::Inspect - Inspect and debug CGI apps with an in-browser UI

SYNOPSIS

  use CGI::Inspect; # This exports inspect()

  print "Content-type: text/html\n\n";

  my $food = "toast";

  for my $i (1..10) {
    print "$i cookies for me to eat...<br>";
    inspect() if $i == 5; # be sure to edit $toast :)
  }

  print "I also like $food!";

DESCRIPTION

This class is a drop-in web based inspector for plain CGI (or CGI-based) applications. Include the library, and then call inspect(). In your server error logs you'll see something like "Please connect to localhost:8080". When you do, you'll be greeted with an inspection UI which includes a stack trace, REPL, and other goodies.

To work it's magic this modules uses Continuity, Devel::LexAlias, Devel::StackTrace::WithLexicals, and their prerequisites (such as PadWalker). Remember that you can always install such things locally for debugging -- no need to install them systemwide (in case you are afraid of the power that they provide).

EXPORTED SUBS

inspect()

This starts the Continuity server and inspector on the configured port (defaulting to 8080). You can pass it parameters which it will then pass on to CGI::Inspect->new. The most useful one is probably port:

  inspect( port => 12345 );

Another useful parameter is plugins. The default is:

    plugins => [qw( BasicLook Exit REPL CallStack )]

PLUGINS

CGI::Inspect comes with a few plugins by default:

  • REPL - A simple Read-Eval-Print prompt

  • StackTrace - A pretty stack trace (with lexical editing!)

  • Exit - Stop inspecting

Creating Plugins

Plugins are easy to create! They are really just subroutines that return a string for what they want printed. All of the built-in plugins actuall inherti from CGI::Inspect::Plugin, which just provides some convenience methods. The main CGI::Inspect module will create an instance of your plugin with Plugin->new, and then will execute it with $plugin->process.

Plugins can, however, make use of Continuity, including utilizing callbacks. Here is the complete source to the 'Exit' plugin, as a fairly simple example.

  package CGI::Inspect::Plugin::Exit;

  use strict;
  use base 'CGI::Inspect::Plugin';

  sub process {
    my ($self) = @_;
    my $exit_link = $self->request->callback_link(
      Exit => sub {
        $self->manager->{do_exit} = 1;
      }
    );
    my $output = qq{
      <div class=dialog title="Exit">
        $exit_link
      </div>
    };
    return $output;
  }

  1;

For now, read the source of the default plugins for further ideas. And of course email the author if you have any questions or ideas!

METHODS

These methods are all internal. All you have to do is call inspect().

CGI::Inspect->new()

Create a new monitor object.

$self->start_inspecting

Load plugins and start inspecting!

$self->start_server

Initialize the Continuity server, and begin the run loop.

$self->display

Display the current page, based on $self->{content}

$self->request

Returns the current request obj

$self->load_plugins

Load all of our plugins.

$self->main

This is executed as the entrypoint for inspector sessions.

SEE ALSO

Carp::REPL

AUTHOR

  Brock Wilcox <awwaiid@thelackthereof.org> - http://thelackthereof.org/

COPYRIGHT

  Copyright (c) 2008-2009 Brock Wilcox <awwaiid@thelackthereof.org>. All rights
  reserved.  This program is free software; you can redistribute it and/or
  modify it under the same terms as Perl itself.