Perl: Escaping the double-quotes expanded from a variable

Question

How can I get

my $name = 'John "FOO" Rambo';

expanded in

<span title=\"The great and mighty $name\"

To something like

<span title=\"The great and mighty John \"FOO\" Rambo\"</span>

rather than

<span title=\"The great and mighty John "FOO" Rambo\"

So that my html tag is not corrupted when generating a page and the name contains " ?

@rbm that does work. Never dealt with perl before :) Can you please post that as an answer? This looks much like some sed expression. Can you please also elaborate on the final `g` thing? Thanks. — Zloj, Oct 06 '15 at 12:49
Please note that `\"` is not a valid HTML escape for `"`. `"` is. — el.pescado - нет войне, Oct 06 '15 at 13:28

score 1 · Accepted Answer · edited Oct 06 '15 at 14:41

1

The proper HTML would be the following:

<span title="The great and mighty John &quot;FOO&quot; Rambo">...</span>

You can obtain it using the following:

use HTML::Entities qw( encode_entities );

my $html = '<span title="' . encode_entities("The great and mighty $name") . '">...</span>';
   -or-
my $html = '<span title="The great and mighty ' . encode_entities($name) . '">...</span>';

You should probably be using a template system. Were you to use Template-Toolkit, the template would be

<span title="The great and mighty [% name | html %]">...</span>

edited Oct 06 '15 at 14:41

ThisSuitIsBlackNot

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answered Oct 06 '15 at 14:29

ikegami

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And this whole time I've been manually escaping HTML entities before passing them to TT. I should have known that would be built in...time to read some docs. – ThisSuitIsBlackNot Oct 06 '15 at 14:45
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@ThisSuitIsBlackNot, It's a builtin FILTER. It doesn't escape single-quotes, so you need to use double-quotes for your attribute value delimiters. – ikegami Oct 06 '15 at 15:00

rbm · Answer 2 · 2015-10-12T10:09:38.953

The correct HTML would be produced by using "

my $name = 'John "FOO" Rambo';
$name =~ s/"/&quot;/g;
my $html = "<span title=\"The great and mighty $name\"/>";
print $html ."\n";

For clarify on your original question:

You can use simple regular expression to substitute quotes. Example:

my $name = 'John "FOO" Rambo';
$name =~ s/"/\\"/g;
my $html = "<span title=\"The great and mighty $name\"/>";
print $html ."\n";

This

$name =~ s/"/\\"/g;

simply says replace all " with \" (but since \ is special character is needs to be escaped as \\".

the g means globally, i.e. all occurences within the string.

(i.e. if you run only $name =~ s/"/\\"/; then $name would be John \"FOO" Rambo, but with g it is John \"FOO\" Rambo)

But this won't produce a valid HTML

Perl: Escaping the double-quotes expanded from a variable

2 Answers2