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Diffstat (limited to 'contrib/perl5/lib/CGI/Carp.pm')
| -rw-r--r-- | contrib/perl5/lib/CGI/Carp.pm | 331 |
1 files changed, 331 insertions, 0 deletions
diff --git a/contrib/perl5/lib/CGI/Carp.pm b/contrib/perl5/lib/CGI/Carp.pm new file mode 100644 index 0000000..e20f754 --- /dev/null +++ b/contrib/perl5/lib/CGI/Carp.pm @@ -0,0 +1,331 @@ +package CGI::Carp; + +=head1 NAME + +B<CGI::Carp> - CGI routines for writing to the HTTPD (or other) error log + +=head1 SYNOPSIS + + use CGI::Carp; + + croak "We're outta here!"; + confess "It was my fault: $!"; + carp "It was your fault!"; + warn "I'm confused"; + die "I'm dying.\n"; + +=head1 DESCRIPTION + +CGI scripts have a nasty habit of leaving warning messages in the error +logs that are neither time stamped nor fully identified. Tracking down +the script that caused the error is a pain. This fixes that. Replace +the usual + + use Carp; + +with + + use CGI::Carp + +And the standard warn(), die (), croak(), confess() and carp() calls +will automagically be replaced with functions that write out nicely +time-stamped messages to the HTTP server error log. + +For example: + + [Fri Nov 17 21:40:43 1995] test.pl: I'm confused at test.pl line 3. + [Fri Nov 17 21:40:43 1995] test.pl: Got an error message: Permission denied. + [Fri Nov 17 21:40:43 1995] test.pl: I'm dying. + +=head1 REDIRECTING ERROR MESSAGES + +By default, error messages are sent to STDERR. Most HTTPD servers +direct STDERR to the server's error log. Some applications may wish +to keep private error logs, distinct from the server's error log, or +they may wish to direct error messages to STDOUT so that the browser +will receive them. + +The C<carpout()> function is provided for this purpose. Since +carpout() is not exported by default, you must import it explicitly by +saying + + use CGI::Carp qw(carpout); + +The carpout() function requires one argument, which should be a +reference to an open filehandle for writing errors. It should be +called in a C<BEGIN> block at the top of the CGI application so that +compiler errors will be caught. Example: + + BEGIN { + use CGI::Carp qw(carpout); + open(LOG, ">>/usr/local/cgi-logs/mycgi-log") or + die("Unable to open mycgi-log: $!\n"); + carpout(LOG); + } + +carpout() does not handle file locking on the log for you at this point. + +The real STDERR is not closed -- it is moved to SAVEERR. Some +servers, when dealing with CGI scripts, close their connection to the +browser when the script closes STDOUT and STDERR. SAVEERR is used to +prevent this from happening prematurely. + +You can pass filehandles to carpout() in a variety of ways. The "correct" +way according to Tom Christiansen is to pass a reference to a filehandle +GLOB: + + carpout(\*LOG); + +This looks weird to mere mortals however, so the following syntaxes are +accepted as well: + + carpout(LOG); + carpout(main::LOG); + carpout(main'LOG); + carpout(\LOG); + carpout(\'main::LOG'); + + ... and so on + +FileHandle and other objects work as well. + +Use of carpout() is not great for performance, so it is recommended +for debugging purposes or for moderate-use applications. A future +version of this module may delay redirecting STDERR until one of the +CGI::Carp methods is called to prevent the performance hit. + +=head1 MAKING PERL ERRORS APPEAR IN THE BROWSER WINDOW + +If you want to send fatal (die, confess) errors to the browser, ask to +import the special "fatalsToBrowser" subroutine: + + use CGI::Carp qw(fatalsToBrowser); + die "Bad error here"; + +Fatal errors will now be echoed to the browser as well as to the log. CGI::Carp +arranges to send a minimal HTTP header to the browser so that even errors that +occur in the early compile phase will be seen. +Nonfatal errors will still be directed to the log file only (unless redirected +with carpout). + +=head2 Changing the default message + +By default, the software error message is followed by a note to +contact the Webmaster by e-mail with the time and date of the error. +If this message is not to your liking, you can change it using the +set_message() routine. This is not imported by default; you should +import it on the use() line: + + use CGI::Carp qw(fatalsToBrowser set_message); + set_message("It's not a bug, it's a feature!"); + +You may also pass in a code reference in order to create a custom +error message. At run time, your code will be called with the text +of the error message that caused the script to die. Example: + + use CGI::Carp qw(fatalsToBrowser set_message); + BEGIN { + sub handle_errors { + my $msg = shift; + print "<h1>Oh gosh</h1>"; + print "Got an error: $msg"; + } + set_message(\&handle_errors); + } + +In order to correctly intercept compile-time errors, you should call +set_message() from within a BEGIN{} block. + +=head1 CHANGE LOG + +1.05 carpout() added and minor corrections by Marc Hedlund + <hedlund@best.com> on 11/26/95. + +1.06 fatalsToBrowser() no longer aborts for fatal errors within + eval() statements. + +1.08 set_message() added and carpout() expanded to allow for FileHandle + objects. + +1.09 set_message() now allows users to pass a code REFERENCE for + really custom error messages. croak and carp are now + exported by default. Thanks to Gunther Birznieks for the + patches. + +1.10 Patch from Chris Dean (ctdean@cogit.com) to allow + module to run correctly under mod_perl. + +=head1 AUTHORS + +Lincoln D. Stein <lstein@genome.wi.mit.edu>. Feel free to redistribute +this under the Perl Artistic License. + + +=head1 SEE ALSO + +Carp, CGI::Base, CGI::BasePlus, CGI::Request, CGI::MiniSvr, CGI::Form, +CGI::Response + +=cut + +require 5.000; +use Exporter; +use Carp; + +@ISA = qw(Exporter); +@EXPORT = qw(confess croak carp); +@EXPORT_OK = qw(carpout fatalsToBrowser wrap set_message); + +$main::SIG{__WARN__}=\&CGI::Carp::warn; +$main::SIG{__DIE__}=\&CGI::Carp::die; +$CGI::Carp::VERSION = '1.101'; +$CGI::Carp::CUSTOM_MSG = undef; + +# fancy import routine detects and handles 'errorWrap' specially. +sub import { + my $pkg = shift; + my(%routines); + grep($routines{$_}++,@_,@EXPORT); + $WRAP++ if $routines{'fatalsToBrowser'} || $routines{'wrap'}; + my($oldlevel) = $Exporter::ExportLevel; + $Exporter::ExportLevel = 1; + Exporter::import($pkg,keys %routines); + $Exporter::ExportLevel = $oldlevel; +} + +# These are the originals +# XXX Why not just use CORE::die etc., instead of these two? GSAR +sub realwarn { CORE::warn(@_); } +sub realdie { CORE::die(@_); } + +sub id { + my $level = shift; + my($pack,$file,$line,$sub) = caller($level); + my($id) = $file=~m|([^/]+)$|; + return ($file,$line,$id); +} + +sub stamp { + my $time = scalar(localtime); + my $frame = 0; + my ($id,$pack,$file); + do { + $id = $file; + ($pack,$file) = caller($frame++); + } until !$file; + ($id) = $id=~m|([^/]+)$|; + return "[$time] $id: "; +} + +sub warn { + my $message = shift; + my($file,$line,$id) = id(1); + $message .= " at $file line $line.\n" unless $message=~/\n$/; + my $stamp = stamp; + $message=~s/^/$stamp/gm; + realwarn $message; +} + +# The mod_perl package Apache::Registry loads CGI programs by calling +# eval. These evals don't count when looking at the stack backtrace. +sub _longmess { + my $message = Carp::longmess(); + my $mod_perl = ($ENV{'GATEWAY_INTERFACE'} + && $ENV{'GATEWAY_INTERFACE'} =~ /^CGI-Perl\//); + $message =~ s,eval[^\n]+Apache/Registry\.pm.*,,s if $mod_perl; + return( $message ); +} + +sub die { + my $message = shift; + my $time = scalar(localtime); + my($file,$line,$id) = id(1); + $message .= " at $file line $line.\n" unless $message=~/\n$/; + &fatalsToBrowser($message) if $WRAP && _longmess() !~ /eval [{\']/m; + my $stamp = stamp; + $message=~s/^/$stamp/gm; + realdie $message; +} + +sub set_message { + $CGI::Carp::CUSTOM_MSG = shift; + return $CGI::Carp::CUSTOM_MSG; +} + +# Avoid generating "subroutine redefined" warnings with the following +# hack: +{ + local $^W=0; + eval <<EOF; +sub confess { CGI::Carp::die Carp::longmess \@_; } +sub croak { CGI::Carp::die Carp::shortmess \@_; } +sub carp { CGI::Carp::warn Carp::shortmess \@_; } +EOF + ; +} + +# We have to be ready to accept a filehandle as a reference +# or a string. +sub carpout { + my($in) = @_; + my($no) = fileno(to_filehandle($in)); + realdie "Invalid filehandle $in\n" unless defined $no; + + open(SAVEERR, ">&STDERR"); + open(STDERR, ">&$no") or + ( print SAVEERR "Unable to redirect STDERR: $!\n" and exit(1) ); +} + +# headers +sub fatalsToBrowser { + my($msg) = @_; + $msg=~s/>/>/g; + $msg=~s/</</g; + $msg=~s/&/&/g; + $msg=~s/\"/"/g; + my($wm) = $ENV{SERVER_ADMIN} ? + qq[the webmaster (<a href="mailto:$ENV{SERVER_ADMIN}">$ENV{SERVER_ADMIN}</a>)] : + "this site's webmaster"; + my ($outer_message) = <<END; +For help, please send mail to $wm, giving this error message +and the time and date of the error. +END + ; + print STDOUT "Content-type: text/html\n\n"; + + if ($CUSTOM_MSG) { + if (ref($CUSTOM_MSG) eq 'CODE') { + &$CUSTOM_MSG($msg); # nicer to perl 5.003 users + return; + } else { + $outer_message = $CUSTOM_MSG; + } + } + + print STDOUT <<END; +<H1>Software error:</H1> +<CODE>$msg</CODE> +<P> +$outer_message; +END + ; +} + +# Cut and paste from CGI.pm so that we don't have the overhead of +# always loading the entire CGI module. +sub to_filehandle { + my $thingy = shift; + return undef unless $thingy; + return $thingy if UNIVERSAL::isa($thingy,'GLOB'); + return $thingy if UNIVERSAL::isa($thingy,'FileHandle'); + if (!ref($thingy)) { + my $caller = 1; + while (my $package = caller($caller++)) { + my($tmp) = $thingy=~/[\':]/ ? $thingy : "$package\:\:$thingy"; + return $tmp if defined(fileno($tmp)); + } + } + return undef; +} + +1; |
