perl - 在 perl 中解码 UTF-8 JSON 的问题

Question

UTF-8 字符在使用 JSON 库处理时会被破坏(这可能类似于 Problem with decoding unicode JSON in perl ，但是设置 binmode 只会产生另一个问题)。

我已将问题简化为以下示例:

(hlovdal) localhost:/tmp/my_test>cat my_test.pl
#!/usr/bin/perl -w
use strict;
use warnings;
use JSON;
use File::Slurp;
use Getopt::Long;
use Encode;

my $set_binmode = 0;
GetOptions("set-binmode" => \$set_binmode);

if ($set_binmode) {
        binmode(STDIN,  ":encoding(UTF-8)");
        binmode(STDOUT, ":encoding(UTF-8)");
        binmode(STDERR, ":encoding(UTF-8)");
}

sub check {
        my $text = shift;
        return "is_utf8(): " . (Encode::is_utf8($text) ? "1" : "0") . ", is_utf8(1): " . (Encode::is_utf8($text, 1) ? "1" : "0"). ". ";
}

my $my_test = "hei på deg";
my $json_text = read_file('my_test.json');
my $hash_ref = JSON->new->utf8->decode($json_text);

print check($my_test), "\$my_test = $my_test\n";
print check($json_text), "\$json_text = $json_text";
print check($$hash_ref{'my_test'}), "\$\$hash_ref{'my_test'} = " . $$hash_ref{'my_test'} .  "\n";

(hlovdal) localhost:/tmp/my_test>

在运行测试时，由于某种原因，文本被压缩为 iso-8859-1。设置 binmode 可以解决它，但会导致其他字符串的双重编码。

(hlovdal) localhost:/tmp/my_test>cat my_test.json 
{ "my_test" : "hei på deg" }
(hlovdal) localhost:/tmp/my_test>file my_test.json 
my_test.json: UTF-8 Unicode text
(hlovdal) localhost:/tmp/my_test>hexdump -c my_test.json 
0000000   {       "   m   y   _   t   e   s   t   "       :       "   h
0000010   e   i       p 303 245       d   e   g   "       }  \n        
000001e
(hlovdal) localhost:/tmp/my_test>
(hlovdal) localhost:/tmp/my_test>perl my_test.pl
is_utf8(): 0, is_utf8(1): 0. $my_test = hei på deg
is_utf8(): 0, is_utf8(1): 0. $json_text = { "my_test" : "hei på deg" }
is_utf8(): 1, is_utf8(1): 1. $$hash_ref{'my_test'} = hei p� deg
(hlovdal) localhost:/tmp/my_test>perl my_test.pl --set-binmode
is_utf8(): 0, is_utf8(1): 0. $my_test = hei på deg
is_utf8(): 0, is_utf8(1): 0. $json_text = { "my_test" : "hei på deg" }
is_utf8(): 1, is_utf8(1): 1. $$hash_ref{'my_test'} = hei på deg
(hlovdal) localhost:/tmp/my_test>

这是什么原因造成的，如何解决？

这是在新安装的最新 Fedora 15 系统上。

(hlovdal) localhost:/tmp/my_test>perl --version | grep version
This is perl 5, version 12, subversion 4 (v5.12.4) built for x86_64-linux-thread-multi
(hlovdal) localhost:/tmp/my_test>rpm -q perl-JSON
perl-JSON-2.51-1.fc15.noarch
(hlovdal) localhost:/tmp/my_test>locale
LANG=en_US.UTF-8
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_PAPER="en_US.UTF-8"
LC_NAME="en_US.UTF-8"
LC_ADDRESS="en_US.UTF-8"
LC_TELEPHONE="en_US.UTF-8"
LC_MEASUREMENT="en_US.UTF-8"
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=
(hlovdal) localhost:/tmp/my_test>

更新:添加 use utf8没有解决，字符仍然没有正确处理(虽然与之前略有不同):

(hlovdal) localhost:/tmp/my_test>perl  my_test.pl
is_utf8(): 1, is_utf8(1): 1. $my_test = hei p� deg
is_utf8(): 0, is_utf8(1): 0. $json_text = { "my_test" : "hei på deg" }
is_utf8(): 1, is_utf8(1): 1. $$hash_ref{'my_test'} = hei p� deg
(hlovdal) localhost:/tmp/my_test>perl  my_test.pl --set-binmode
is_utf8(): 1, is_utf8(1): 1. $my_test = hei på deg
is_utf8(): 0, is_utf8(1): 0. $json_text = { "my_test" : "hei på deg" }
is_utf8(): 1, is_utf8(1): 1. $$hash_ref{'my_test'} = hei på deg
(hlovdal) localhost:/tmp/my_test>

正如 perlunifaq 所指出的

Can I use Unicode in my Perl sources?

Yes, you can! If your sources are UTF-8 encoded, you can indicate that with the use utf8 pragma.

use utf8;

This doesn't do anything to your input, or to your output. It only influences the way your sources are read. You can use Unicode in string literals, in identifiers (but they still have to be "word characters" according to \w ), and even in custom delimiters.

Answer 1

你用 UTF-8 保存了你的程序，但忘记告诉 Perl。添加 use utf8; .

此外，您的编程太复杂了。 JSON 函数 DWYM。要检查内容，请使用 Devel::Peek。

use utf8; # for the following line
my $my_test = 'hei på deg';

use Devel::Peek qw(Dump);
use File::Slurp (read_file);
use JSON qw(decode_json);

my $hash_ref = decode_json(read_file('my_test.json'));

Dump $hash_ref; # Perl character strings
Dump $my_test;  # Perl character string