perl uri_escape_utf8 with arabic - perl

Question

I am trying to escape some Arabic to LWP::UserAgent. I am testing this with a script below:
my $files = "/home/root/temp.txt";
unlink ($files);
open (OUTFILE, '>>', $files);
my $text = "ضثصثضصثشس";
print OUTFILE uri_escape_utf8($text)."\n";
close (OUTFILE);
However, this seems to cause the following:
%C3%96%C3%8B%C3%95%C3%8B%C3%96%C3%95%C3%8B%C3%94%C3%93
which is not correct. Any pointers to what I need to do in order to escape this correctly?
Thank you for your help in advance.
Regards,
Olli

Answer 1

Perl consideres your source file to be encoded as Latin-1 until you tell it to use utf8. If we do that, the string "ضثصثضصثشس" does not contain some jumbled bytes, but is rather a string of codepoints.
The uri_escape_utf8 expects a string of codepoints (not bytes!), encodes them, and then URI-escapes them. Ergo, the correct thing to do is
use utf8;
use URI::Escape;
print uri_escape_utf8("ضثصثضصثشس"), "\n";
Output: %D8%B6%D8%AB%D8%B5%D8%AB%D8%B6%D8%B5%D8%AB%D8%B4%D8%B3
If we fail to use utf8, then uri_escape_utf8 gets a string of bytes (which are accidentally encoded in UTF8), so we should have used uri_escape:
die "This is the wrong way to do it";
use URI::Escape;
print uri_escape("ضثصثضصثشس"), "\n";
which produces the same output as above – but only by accident.
Using uri_escape_utf8 whith a bytestring (that would decode to arabic characters) produces the totally wrong
%C3%98%C2%B6%C3%98%C2%AB%C3%98%C2%B5%C3%98%C2%AB%C3%98%C2%B6%C3%98%C2%B5%C3%98%C2%AB%C3%98%C2%B4%C3%98%C2%B3
because this effectively double-encodes the data. It is the same as
use utf8;
use URI::Escape;
use Encode;
print uri_escape(encode "utf8", encode "utf8", "ضثصثضصثشس"), "\n";
Edit: So you used CP-1256, which is a non-portable single byte encoding. It is unable to encode arbitrary Unicode characters, and should therefore be avoided along with other pre-Unicode encodings. You didn't declare your encoding, so perl thinks you meant Latin-1. This means that what you saw as "ضثصثضصثشس" was actually the byte stream D6 CB D5 CB D6 D5 CB D4 D3, which decodes to some unprintable junk in Latin-1.
Edit: So you want to decode command line arguments. The Encode::Locale module should manage this. Before accessing any parameters from #ARGV, do
use Encode::Locale;
decode_argv(Encode::FB_CROAK); # possibly: BEGIN { decode_argv(...) }
or use the locale pseudoencoding which it provides:
my $decoded_string = decode "locale" $some_binary_data;
Use this as a part in the overall strategy of decoding all input, and always encoding your output.