package Dancer2::Core::Error;
# ABSTRACT: Class representing fatal errors
$Dancer2::Core::Error::VERSION = '0.140001';
use Moo;
use Carp;
use Dancer2::Core::Types;
use Dancer2::Core::HTTP;
use Data::Dumper;
use Dancer2::FileUtils 'path';
has show_errors => (
is => 'ro',
isa => Bool,
default => sub {
$_[0]->context->app->setting('show_errors') if $_[0]->has_context;
},
);
has charset => (
is => 'ro',
isa => Str,
default => sub {'UTF-8'},
);
has type => (
is => 'ro',
isa => Str,
default => sub {'Runtime Error'},
);
has title => (
is => 'ro',
isa => Str,
lazy => 1,
builder => '_build_title',
);
sub _build_title {
my ($self) = @_;
my $title = 'Error ' . $self->status;
if ( my $msg = Dancer2::Core::HTTP->status_message($self->status) ) {
$title .= ' - ' . $msg;
}
return $title;
}
has template => (
is => 'ro',
# isa => sub { ref($_[0]) eq 'SCALAR' || ReadableFilePath->(@_) },
lazy => 1,
builder => '_build_error_template',
);
sub _build_error_template {
my ($self) = @_;
# look for a template named after the status number.
# E.g.: views/404.tt for a TT template
return $self->status
if -f $self->context->app->engine('template')
->view_pathname( $self->status );
return undef;
}
has static_page => (
is => 'ro',
lazy => 1,
builder => '_build_static_page',
);
sub _build_static_page {
my ($self) = @_;
# TODO there must be a better way to get it
my $public_dir = $ENV{DANCER_PUBLIC}
|| ( $self->has_context
&& path( $self->context->app->config_location, 'public' ) );
my $filename = sprintf "%s/%d.html", $public_dir, $self->status;
open my $fh, $filename or return undef;
local $/ = undef; # slurp time
return <$fh>;
}
sub default_error_page {
my $self = shift;
require Template::Tiny;
my $uri_base = $self->has_context ?
$self->context->request->uri_base : '';
my $opts = {
title => $self->title,
charset => $self->charset,
content => $self->message,
version => Dancer2->VERSION,
uri_base => $uri_base,
};
Template::Tiny->new->process( \<<"END_TEMPLATE", $opts, \my $output );
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<title>[% title %]</title>
<link rel="stylesheet" href="[% uri_base %]/css/error.css" />
<meta http-equiv="Content-type" content="text/html; charset='[% charset %]'" />
</head>
<body>
<h1>[% title %]</h1>
<div id="content">
[% content %]
</div>
<div id="footer">
Powered by <a href="http://perldancer.org/">Dancer2</a> [% version %]
</div>
</body>
</html>
END_TEMPLATE
return $output;
}
has status => (
is => 'ro',
default => sub {500},
isa => Num,
);
has message => (
is => 'ro',
isa => Str,
);
sub full_message {
my ($self) = @_;
my $html_output = "<h2>" . $self->type . "</h2>";
$html_output .= $self->backtrace;
$html_output .= $self->environment;
return $html_output;
}
has serializer => (
is => 'ro',
isa => ConsumerOf ['Dancer2::Core::Role::Serializer'],
predicate => 1,
);
has session => (
is => 'ro',
isa => ConsumerOf ['Dancer2::Core::Role::Session'],
);
has context => (
is => 'ro',
isa => InstanceOf ['Dancer2::Core::Context'],
predicate => 1,
);
sub BUILD {
my ($self) = @_;
$self->has_context &&
$self->context->app->execute_hook( 'core.error.init', $self );
}
has exception => (
is => 'ro',
isa => Str,
predicate => 1,
);
has response => (
is => 'rw',
lazy => 1,
default => sub {
$_[0]->has_context
? $_[0]->context->response
: Dancer2::Core::Response->new;
},
);
has content_type => (
is => 'ro',
lazy => 1,
default => sub {
my $self = shift;
$self->has_serializer
? $self->serializer->content_type
: 'text/html'
},
);
has content => (
is => 'ro',
lazy => 1,
default => sub {
my $self = shift;
# Apply serializer
if ( $self->has_serializer ) {
my $content = {
message => $self->message,
title => $self->title,
status => $self->status,
};
$content->{exception} = $self->exception
if $self->has_exception;
return $self->serializer->serialize($content);
}
# Otherwise we check for a template, for a static file and,
# if all else fail, the default error page
if ( $self->has_context and $self->template ) {
return $self->context->app->template(
$self->template,
{ title => $self->title,
content => $self->message,
exception => $self->exception,
status => $self->status,
}
);
}
if ( my $content = $self->static_page ) {
return $content;
}
return $self->default_error_page;
},
);
sub throw {
my $self = shift;
$self->response(shift) if @_;
croak "error has no response to throw at" unless $self->response;
$self->has_context &&
$self->context->app->execute_hook( 'core.error.before', $self );
my $message = $self->content;
$message .= "\n\n" . $self->exception
if $self->show_errors && defined $self->exception;
$self->response->status( $self->status );
$self->response->content_type( $self->content_type );
$self->response->content($message);
$self->has_context &&
$self->context->app->execute_hook('core.error.after', $self->response);
$self->response->halt(1);
return $self->response;
}
sub backtrace {
my ($self) = @_;
my $message =
qq|<pre class="error">| . _html_encode( $self->message ) . "</pre>";
# the default perl warning/error pattern
my ( $file, $line ) = ( $message =~ /at (\S+) line (\d+)/ );
# the Devel::SimpleTrace pattern
( $file, $line ) = ( $message =~ /at.*\((\S+):(\d+)\)/ )
unless $file and $line;
# no file/line found, cannot open a file for context
return $message unless ( $file and $line );
# file and line are located, let's read the source Luke!
my $fh = open_file( '<', $file ) or return $message;
my @lines = <$fh>;
close $fh;
my $backtrace = $message;
$backtrace
.= qq|<div class="title">| . "$file around line $line" . "</div>";
$backtrace .= qq|<pre class="content">|;
$line--;
my $start = ( ( $line - 3 ) >= 0 ) ? ( $line - 3 ) : 0;
my $stop =
( ( $line + 3 ) < scalar(@lines) ) ? ( $line + 3 ) : scalar(@lines);
for ( my $l = $start; $l <= $stop; $l++ ) {
chomp $lines[$l];
if ( $l == $line ) {
$backtrace
.= qq|<span class="nu">|
. tabulate( $l + 1, $stop + 1 )
. qq|</span> <span style="color: red;">|
. _html_encode( $lines[$l] )
. "</span>\n";
}
else {
$backtrace
.= qq|<span class="nu">|
. tabulate( $l + 1, $stop + 1 )
. "</span> "
. _html_encode( $lines[$l] ) . "\n";
}
}
$backtrace .= "</pre>";
return $backtrace;
}
sub tabulate {
my ( $number, $max ) = @_;
my $len = length($max);
return $number if length($number) == $len;
return " $number";
}
sub dumper {
my $obj = shift;
# Take a copy of the data, so we can mask sensitive-looking stuff:
my %data = %$obj;
my $censored = _censor( \%data );
#use Data::Dumper;
my $dd = Data::Dumper->new( [ \%data ] );
$dd->Terse(1)->Quotekeys(0)->Indent(1);
my $content = $dd->Dump();
$content =~ s{(\s*)(\S+)(\s*)=>}{$1<span class="key">$2</span>$3 =>}g;
if ($censored) {
$content
.= "\n\nNote: Values of $censored sensitive-looking keys hidden\n";
}
return $content;
}
sub environment {
my ($self) = @_;
my $request = $self->has_context ? $self->context->request : 'TODO';
my $r_env = {};
$r_env = $request->env if defined $request;
my $env =
qq|<div class="title">Environment</div><pre class="content">|
. dumper($r_env)
. "</pre>";
my $settings =
qq|<div class="title">Settings</div><pre class="content">|
. dumper( $self->app->settings )
. "</pre>";
my $source =
qq|<div class="title">Stack</div><pre class="content">|
. $self->get_caller
. "</pre>";
my $session = "";
if ( $self->session ) {
$session =
qq[<div class="title">Session</div><pre class="content">]
. dumper( $self->session->data )
. "</pre>";
}
return "$source $settings $session $env";
}
sub get_caller {
my ($self) = @_;
my @stack;
my $deepness = 0;
while ( my ( $package, $file, $line ) = caller( $deepness++ ) ) {
push @stack, "$package in $file l. $line";
}
return join( "\n", reverse(@stack) );
}
# private
# Given a hashref, censor anything that looks sensitive. Returns number of
# items which were "censored".
sub _censor {
my $hash = shift;
if ( !$hash || ref $hash ne 'HASH' ) {
carp "_censor given incorrect input: $hash";
return;
}
my $censored = 0;
for my $key ( keys %$hash ) {
if ( ref $hash->{$key} eq 'HASH' ) {
$censored += _censor( $hash->{$key} );
}
elsif ( $key =~ /(pass|card?num|pan|secret)/i ) {
$hash->{$key} = "Hidden (looks potentially sensitive)";
$censored++;
}
}
return $censored;
}
# Replaces the entities that are illegal in (X)HTML.
sub _html_encode {
my $value = shift;
$value =~ s/&/&/g;
$value =~ s/</</g;
$value =~ s/>/>/g;
$value =~ s/'/'/g;
$value =~ s/"/"/g;
return $value;
}
sub _render_html {
my $self = shift;
# error_template defaults to something, always
my $template_name = $self->error_template;
my $ops = {
title => $self->title,
content => $self->message,
status => $self->status,
defined $self->exception ? ( exception => $self->exception ) : (),
};
my $content = $self->template->apply_renderer( $template_name, $ops );
$self->response->status( $self->status );
$self->response->header( 'Content-Type' => 'text/html' );
return $content;
}
1;
__END__
=pod
=head1 NAME
Dancer2::Core::Error - Class representing fatal errors
=head1 VERSION
version 0.140001
=head1 SYNOPSIS
# taken from send_file:
use Dancer2::Core::Error;
my $error = Dancer2::Core::Error->new(
status => 404,
message => "No such file: `$path'"
);
Dancer2::Core::Response->set($error->render);
=head1 DESCRIPTION
With Dancer2::Core::Error you can throw reasonable-looking errors to the user
instead of crashing the application and filling up the logs.
This is usually used in debugging environments, and it's what Dancer2 uses as
well under debugging to catch errors and show them on screen.
=head1 ATTRIBUTES
=head2 show_errors
=head2 charset
=head2 type
The error type.
=head2 title
The title of the error page.
This is only an attribute getter, you'll have to set it at C<new>.
=head2 status
The status that caused the error.
This is only an attribute getter, you'll have to set it at C<new>.
=head2 message
The message of the error page.
=head1 METHODS
=head2 my $error=new Dancer2::Core::Error(status => 404, message => "No such file: `$path'");
Create a new Dancer2::Core::Error object. For available arguments see ATTRIBUTES.
=head2 supported_hooks ();
=head2 throw($response)
Populates the content of the response with the error's information.
If I<$response> is not given, acts on the I<context>
attribute's response.
=head2 backtrace
Create a backtrace of the code where the error is caused.
This method tries to find out where the error appeared according to the actual
error message (using the C<message> attribute) and tries to parse it (supporting
the regular/default Perl warning or error pattern and the L<Devel::SimpleTrace>
output) and then returns an error-highlighted C<message>.
=head2 tabulate
Small subroutine to help output nicer.
=head2 environment
A main function to render environment information: the caller (using
C<get_caller>), the settings and environment (using C<dumper>) and more.
=head2 get_caller
Creates a stack trace of callers.
=head1 FUNCTIONS
=head2 _censor
An private function that tries to censor out content which should be protected.
C<dumper> calls this method to censor things like passwords and such.
=head2 my $string=_html_encode ($string);
Private function that replaces illegal entities in (X)HTML with their
escaped representations.
html_encode() doesn't do any UTF black magic.
=head2 dumper
This uses L<Data::Dumper> to create nice content output with a few predefined
options.
=head1 AUTHOR
Dancer Core Developers
=head1 COPYRIGHT AND LICENSE
This software is copyright (c) 2014 by Alexis Sukrieh.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
=cut