How to convert any character encoding to UTF8 on PHP

Question

I'm working on a web crawler that grabs data from sites all over the world, and is dealing with distinct languages and encodings.

Currently I'm using the following function, and it works in 99% of the cases. But there is this 1% that is giving me headaches.

function convertEncoding($str) {
    return iconv(mb_detect_encoding($str), "UTF-8", $str);
}

Answer 1

Rather than blindly trying to detect the encoding, you should first check if the page that you downloaded has a listed character set. The character set may be set in the HTTP response header, for example:

Content-Type:text/html; charset=utf-8

Or in the HTML as a meta tag, for example:

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 

Only if neither are available then try to guess the encoding with mb_detect_encoding() or other methods.

Answer 2

It's not possible to detect character set of a string in 100% rate since some character sets are subset of some others. Try setting character set explicitly if possible without mixing iconv and mbstring functions. I recommend using a function like this and supplying from charset whenever possible:

function convertEncoding($str, $from = 'auto', $to = "UTF-8") {
    if($from == 'auto') $from = mb_detect_encoding($str);
    return mb_convert_encoding ($str , $to, $from); 
}

Answer 3

You can try utf_encode($str).

http://www.php.net/manual/en/function.utf8-encode.php#89789

Or you can replace the content type meta tag with

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 

from header of crawled content