"无法解码宽字符的字符串"出现在一个奇怪的地方

Question

我试图在UTF8编码文本上使用XML :: RAI perl模块,我仍然有错误我真的不明白...这里是代码(它不应该做任何有用的事情):

use HTTP::Request;
use LWP::UserAgent;
use XML::RAI;
use Encode;

my $ua = LWP::UserAgent->new;


sub readFromWeb{
    my $address = shift;
    my $request = HTTP::Request->new( GET => $address );
    my $response = $ua->request( $request );
    return unless $response->code == 200;

    return decode("utf8", $response->content());
}

sub readFromRSS{
    my $address=shift;
    my $content = readFromWeb $address;
    my $rai = XML::RAI->parse_string($content);
          #this line "causes" the error
}


readFromRSS("http://aktualne.centrum.cz/export/rss-hp.phtml");
     #I am testing it on this particular RSS

错误是:

 Cannot decode string with wide characters at /usr/lib/perl5/5.8.8/i686-linux/Encode.pm line 166.

我不知道这是我的错还是XML :: RAI的错.如果已经从utf8中解码了$ content,我看不出这些宽字符的位置...

编辑:由于某种原因我仍然不明白,删除"解码"部分实际上解决了问题.

Answer 1

问题是双重解码.XML::RAI::parse_string()显然需要一个UTF-8编码的文档并进行解码.如果传入已解码的字符串,则第二次解码将失败,当然:

#!/usr/bin/perl
use strict;
use warnings;

use Encode qw( decode );
use LWP::Simple qw( get );

my $xml = get("http://aktualne.centrum.cz/export/rss-hp.phtml");

$xml = decode('UTF-8', $xml);
$xml = decode('UTF-8', $xml); # dies: Cannot decode string with wide characters ...

所以,跳过这decode()一步,你会没事的.