I have a string that I know is utf8 but perl's utf8 flag is not set on the string and I have not run decode('UTF-8' => $string).

If I print this string to a filehandle with :utf8 layer set (via binmode or at open), will the utf8 be garbled somehow, since the string is not marked/known utf8? Or will everything be OK, since the utf8 string is in byte mode anyway?

I have read perlunicode, perluniintro, utf8, encoding, Encode and other docs and this is one thing I cannot figure out.

This is important because LWP does not seem to set the utf8 flag for UTF-8 encoded HTML strings, even when UTF-8 is sent in the appropriate HTTP header. And I am doing some scraping on these pages and printing some of the text back out on a filehandle where I set the layer to ':utf8' and I'm hoping this will Just Work.

If not, I need to add some code that takes HTML::Encoding to the HTTP response and even the HTML itself to sniff out the encoding and, if present, call Encode::decode() on it.

An example of LWP not setting the utf8 flag on UTF-8 encoded HTML: 

use strict;
use warnings;

use LWP::Simple;
use Encode;

#I have confirmed the correct HTTP header sent here
my $html = get('http://-redacted-/file.utf8.html');

print "utf8: " . utf8::is_utf8($html) . "\n";
#Output is utf8: 

my $html2 = decode('UTF-8' => $html);

print "utf8: " . utf8::is_utf8($html2) . "\n";
#Output is utf8: 1

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In reply to Printing undecoded utf8 -- safe? by ryantate

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