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perl::critic::policy::inputoutput::requireencodingwithutf8layer(3) [centos man page]

Perl::Critic::Policy::InputOutput::RequireEncodingWithUTUseryContributed Perl DoPerl::Critic::Policy::InputOutput::RequireEncodingWithUTF8Layer(3)

NAME

       Perl::Critic::Policy::InputOutput::RequireEncodingWithUTF8Layer - Write "open $fh, q{<:encoding(UTF-8)}, $filename;" instead of "open $fh,
       q{{<:utf8}, $filename;".

AFFILIATION

       This Policy is part of the core Perl::Critic distribution.

DESCRIPTION

       Use of the ":utf8" I/O layer (as opposed to ":encoding(UTF8)" or ":encoding(UTF-8)") was suggested in the Perl documentation up to version
       5.8.8. This may be OK for output, but on input ":utf8" does not validate the input, leading to unexpected results.

       An exploit based on this behavior of ":utf8" is exhibited on PerlMonks at <http://www.perlmonks.org/?node_id=644786>. The exploit involves
       a string read from an external file and sanitized with "m/^(w+)$/", where $1 nonetheless ends up containing shell meta-characters.

       To summarize:

	open $fh, '<:utf8', 'foo.txt';		   # BAD
	open $fh, '<:encoding(UTF8)', 'foo.txt';   # GOOD
	open $fh, '<:encoding(UTF-8)', 'foo.txt';  # BETTER

       See the Encode documentation for the difference between "UTF8" and "UTF-8". The short version is that "UTF-8" implements the Unicode
       standard, and "UTF8" is liberalized.

       For consistency's sake, this policy checks files opened for output as well as input, For complete coverage it also checks "binmode()"
       calls, where the direction the operation can not be determined.

CONFIGURATION

       This Policy is not configurable except for the standard options.

NOTES

       Because "Perl::Critic" does a static analysis, this policy can not detect cases like

	my $encoding = ':utf8';
	binmode $fh, $encoding;

       where the encoding is computed.

SEE ALSO

       PerlIO

       Encode

       "perldoc -f binmode"

       <http://www.socialtext.net/perl5/index.cgi?the_utf8_perlio_layer>

       <http://www.perlmonks.org/?node_id=644786>

AUTHOR

       Thomas R. Wyant, III wyant at cpan dot org

COPYRIGHT

       Copyright (c) 2010-2011 Thomas R. Wyant, III

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

perl v5.16.3							    2014-06-09	Perl::Critic::Policy::InputOutput::RequireEncodingWithUTF8Layer(3)

Check Out this Related Man Page

Perl::Critic::Policy::InputOutput::ProhibitTwoArgOpen(3)User Contributed Perl DocumentatioPerl::Critic::Policy::InputOutput::ProhibitTwoArgOpen(3)

NAME

       Perl::Critic::Policy::InputOutput::ProhibitTwoArgOpen - Write "open $fh, q{<}, $filename;" instead of "open $fh, "<$filename";".

AFFILIATION

       This Policy is part of the core Perl::Critic distribution.

DESCRIPTION

       The three-argument form of "open" (introduced in Perl 5.6) prevents subtle bugs that occur when the filename starts with funny characters
       like '>' or '<'.  The IO::File module provides a nice object-oriented interface to filehandles, which I think is more elegant anyway.

	 open( $fh, '>output.txt' );	      # not ok
	 open( $fh, q{>}, 'output.txt' );     # ok

	 use IO::File;
	 my $fh = IO::File->new( 'output.txt', q{>} ); # even better!

       It's also more explicitly clear to define the input mode of the file, as in the difference between these two:

	 open( $fh, 'foo.txt' );       # BAD: Reader must think what default mode is
	 open( $fh, '<', 'foo.txt' );  # GOOD: Reader can see open mode

       This policy will not complain if the file explicitly states that it is compatible with a version of perl prior to 5.6 via an include
       statement, e.g. by having "require 5.005" in it.

CONFIGURATION

       This Policy is not configurable except for the standard options.

NOTES

       There are two cases in which you are forced to use the two-argument form of open. When re-opening STDIN, STDOUT, or STDERR, and when doing
       a safe pipe open, as described in perlipc.

SEE ALSO

       IO::Handle

       IO::File

AUTHOR

       Jeffrey Ryan Thalhammer <jeff@imaginative-software.com>

COPYRIGHT

       Copyright (c) 2005-2011 Imaginative Software Systems.  All rights reserved.

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

perl v5.16.3							    2014-06-09		  Perl::Critic::Policy::InputOutput::ProhibitTwoArgOpen(3)
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