无法使用PHP对UTF8中的CSV文件进行编码

Question

I've been trying, for some time now, to export a properly encoded and formated CSV file with PHP. But it's just not working. I've tried every tip in every CSV/PHP related thread on SOF, I've checked that the data in my database is UTF-8, it is. I've tried stuff like utf8_encode() on the whole CSV-line, I've checked that the actual PHP file is encoded in UTF-8, but still no success. When I run the file on http://csvlint.io/ I just get:

Your CSV appears to be encoded in ASCII-8BIT. We recommend you use UTF-8.

But I can't find a trace of any other encoding than UTF-8 anywhere in my code.. Basically this is my code:

First, I put all my CSV-rows in an array, then do this:

if (count($array) == 0)
{
    return NULL;
}
ob_start();
$df = fopen("php://output", 'w');
$csv = utf8_encode("header1|header2|header3|header4|header5|header6|header7
");
foreach($array as $line) {
    $csv .= $line . "
";
}
setlocale(LC_ALL, 'sv_SE', "swedish");
fwrite($df, "\xEF\xBB\xBF".$csv);
fclose($df);
return ob_get_clean();

And these are the headers sent:

$now = gmdate("D, d M Y H:i:s");
header("Expires: Tue, 03 Jul 2001 06:00:00 GMT");
header("Cache-Control: max-age=0, no-cache, must-revalidate, proxy-revalidate");
header("Last-Modified: {$now} GMT");
header("Content-Encoding: UTF-8");
header("Content-Type: text/csv; charset=UTF-8");
header("Content-Type: application/force-download");
header("Content-Type: application/octet-stream");
header("Content-Type: application/download");
header("Content-Disposition: attachment;filename={$filename}");
header("Content-Transfer-Encoding: binary");

Any ideas?

Answer 1

The issue is the byte-order mark you're prepending to the output in this line:

fwrite($df, "\xEF\xBB\xBF".$csv);

If you change this to simply

fwrite($df, $csv);

You should find the resulting file validates just fine (or at least, the validator doesn't complain about its encoding).

Arguably this is a problem with the validator, since as the Wikipedia article notes,

The Unicode Standard permits the BOM in UTF-8, but does not require or recommend its use.

I don't recommend you use it either, as most software seems not to recognize byte-order marks. But if you must or you simply prefer to, you can safely ignore the warning from CSVLint.

---

Since that is apparently not the issue, the next thing I'd look at is whether or not the data is being retrieved from the database in UTF-8. (I'll take your word you've already checked carefully to make sure the data is being stored in UTF-8.) If you're using MySQL, this will depend on the configuration of the database server and any options you may be sending the database after connection.

The PHP manual has a section on character sets and MySQL, and there is also this helpful article about using PHP and MySQL together with UTF-8 data. If you're using a different database system, it likely has equivalent configuration options that should be checked.

The only other suggestions I can make are that you

• Move the call to setlocale higher in the script, before string concatenation begins in the foreach loop. (I don't think this setting affects simple concatenation, but I'm not certain.)

• Remove the Content-Encoding header from your output, as it is invalid the way it is currently being used.