1CGI::Application::PlugiUns:e:rErCroonrtPraigbeu(t3e)d PeCrGlI:D:oAcpupmleinctaattiioonn::Plugin::ErrorPage(3)
2
6 CGI::Application::Plugin::ErrorPage - A simple error page plugin for
7 CGI::Application
8
10 use CGI::Application::Plugin::ErrorPage 'error';
11 sub my_run_mode {
13 my $self = shift;
14 eval { .... };
16 if ($@) {
18 # Send the gory details to the log for the developers
19 warn "$@";
20 # Send a comprehensible message to the users
22 return $self->error(
23 title => "Technical Failure',
24 msg => "There was a techical failure during the operation.",
25 );
26 }
27 }
29
31 This plugin provides a shortcut for the common need of returning a
32 simple error message to the user.
33 You are encouraged to provide a template file so that the error
35 messages can be presented with a design consistent with the rest of
36 your application.
37 A simple design is provided below to get to you started.
39 A better default error page.
41 If you don't install an AUTOLOAD run mode in the normal way in "setup",
42 this plugin will automatically install a reasonable default at the
43 "prerun" stage, which returns an error page like this:
44 return $c->error(
46 title => 'The requested page was not found.',
47 msg => "(The page tried was: ".$c->get_current_runmode.")"
48 );
49 Relation to error_mode()
51 CGI::Application includes "error_mode()" to provide custom handling
52 when the application dies. This error() routine provides a shortcut
53 for displaying error messages to the user. So, they both have a place
54 on their own, and it could make sense to use them together. In your
55 'error_mode' routine, you might call error() to return a message to the
56 user:
57 $self->error( title => 'Technical Failure', msg => 'There was a technical failure' );
59 Suggested Uses
61 Some common cases for returning error messages to the user include:
62 * "Technical Failure" - The software failed unexpectedly
64 * "Insufficient Information" - some required query parameter was missing
65 * "Request Not Understood" - Some value we received in the query just didn't make sense.
66 Silliness
68 [22:36] <rjbs> Techno Failure. We were cruising along and rocking out while fulfilling your request, but then the music stopped and we sort of got distracted.
69 [22:36] <rjbs> Tek Failure. Too busy reading Shatner novels to respond to your request.
70
72 error()
73 return $self->error(
74 title => "Technical Failure',
75 msg => "There was a techical failure during the operation",
76 );
77 Nothing fancy, just a shortcut to load a template meant to display
79 errors. I've used it for the past several years, and it's been very
80 handy to always have around on projects to quickly write error handling
81 code.
82 It tries to load a template file named 'error.html' to display the
84 error page.
85 If you want to use a different location, I recommend putting something
87 like this in your base class, so you only have to provide your error
88 template location once.
89 # In this case, intentionally *don't* import 'error' to avoid a "redefined" warning.
91 use CGI::Application::Plugin::ErrorPage;
92 sub error {
93 my $c = shift;
94 return $c->CGI::Application::Plugin::ErrorPage::error(
95 tmpl => $self->cfg('ROOT_URI').'/path/to/my/alternate/error/file.html',
96 @_,
97 );
98 }
99 This module intentionally ignores any "tmpl_path()" set by application,
101 since this is usually an indication of where the intended file is
102 located, not the error template. This exceptional handling of the
103 "tmpl_path()" is one of the only value added bits of logic that this
104 plugin adds. The rest of it is primarily a simple recommendation for
105 error page handling wrapped up as a module.
106 If you don't want this behavior, it's simple enough just to roll your
108 own error() page method and skip using this plugin. Here's the simple
109 essential code:
110 use Params::Validate ':all';
112 sub error {
113 my $self = shift;
114 my %p = validate(@_, { title => SCALAR, msg => SCALAR });
115 my $t = $self->load_tmpl;
116 $t->param( title => $p{title}, msg => $p{msg} );
117 return $t->output;
118 }
119 Example error.html
121 Here's a very basic example of an "error.html" file to get you started.
122 <!DOCTYPE html
124 PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
125 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
126 <html xmlns="http://www.w3.org/1999/xhtml" lang="en-US" xml:lang="en-US">
127 <head>
128 <title><!-- tmpl_var title escape=HTML --></title>
129 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
130 </head>
131 <body>
132 <h1><!-- tmpl_var title escape=HTML--></h1>
133 <p><!-- tmpl_var msg escape=HTML --></p>
134 </body>
135 </html>
136 We manage site-wide designs with Dreamweaver and keep a basic
138 'error.html' that uses a generic Dreamweaver 'page.dwt' template with
139 standard EditableRegion names. That way, we can copy this error.html
140 into a new Dreamweaver-managed project and have the new design applied
141 to it easily through Dreamweaver.
142
144 Ask for help on the CGI::Application mailing list. Report bugs and
145 wishes through the rt.cpan.org bug tracker.
146
148 Mark Stosberg
149 CPAN ID: MARKSTOS
150 mark@summersault.com
151
153 This program is free software; you can redistribute it and/or modify it
154 under the same terms as Perl itself.
155 The full text of the license can be found in the LICENSE file included
157 with this module.
158
160 perl(1).
161perl v5.28.0 2018-07C-G1I4::Application::Plugin::ErrorPage(3)