Nrthugu

I'd like to add one thing to chazomaticus' excellent answer:

Don't forget the META tag either (like this, or the HTML4 or XHTML version of it):

<meta charset="utf-8">

That seems trivial, but IE7 has given me problems with that before.

I was doing everything right; the database, database connection and Content-Type HTTP header were all set to UTF-8, and it worked fine in all other browsers, but Internet Explorer still insisted on using the "Western European" encoding.

It turned out the page was missing the META tag. Adding that solved the problem.

Edit:

The W3C actually has a rather large section dedicated to I18N. They have a number of articles related to this issue – describing the HTTP, (X)HTML and CSS side of things:

• FAQ: Changing (X)HTML page encoding to UTF-8


• Declaring character encodings in HTML


• Tutorial: Character sets & encodings in XHTML, HTML and CSS


• Setting the HTTP charset parameter

They recommend using both the HTTP header and HTML meta tag (or XML declaration in case of XHTML served as XML).

In addition to setting default_charset in php.ini, you can send the correct charset using header() from within your code, before any output:

header('Content-Type: text/html; charset=utf-8');

Working with Unicode in PHP is easy as long as you realize that most of the string functions don't work with Unicode, and some might mangle strings completely. PHP considers "characters" to be 1 byte long. Sometimes this is okay (for example, explode() only looks for a byte sequence and uses it as a separator -- so it doesn't matter what actual characters you look for). But other times, when the function is actually designed to work on characters, PHP has no idea that your text has multi-byte characters that are found with Unicode.

A good library to check into is phputf8. This rewrites all of the "bad" functions so you can safely work on UTF8 strings. There are extensions like the mbstring extension that try to do this for you, too, but I prefer using the library because it's more portable (but I write mass-market products, so that's important for me). But phputf8 can use mbstring behind the scenes, anyway, to increase performance.

Old topic, I know. Found an issue with someone using PDO and the answer was to use this for the PDO Connection string:

$pdo = new PDO(

    'mysql:host=mysql.example.com;dbname=example_db',

    "username",

    "password",

    array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"));

The site I took this from is down, was able to get it using google cache luckily.

In my case, I was using mb_split, which uses regex. Therefore I also had to manually make sure the regex encoding was utf-8 by doing mb_regex_encoding('UTF-8');

As a side note, I also discovered by running mb_internal_encoding() that the internal encoding wasn't utf-8, and I changed that by running mb_internal_encoding("UTF-8");.

First of all if you are in < 5.3PHP then no. You've got a ton of problems to tackle.

I am surprised that none has mentioned the intl library, the one that has good support for unicode, graphemes, string operations , localisation and many more, see below.

I will quote some information about unicode support in PHP by Elizabeth Smith's slides at PHPBenelux'14

INTL

Good:

• Wrapper around ICU library


• Standardised locales, set locale per script


• Number formatting


• Currency formatting


• Message formatting (replaces gettext)


• Calendars, dates, timezone and time


• Transliterator


• Spoofchecker


• Resource bundles


• Convertors


• IDN support


• Graphemes


• Collation


• Iterators

Bad:

• Does not support zend_multibite


• Does not support HTTP input output conversion


• Does not support function overloading

mb_string

• Enables zend_multibyte support


• Supports transparent HTTP in/out encoding


• Provides some wrappers for funtionallity such as strtoupper

ICONV

• Primary for charset conversion


• Output buffer handler


• mime encoding functionality


• conversion


• some string helpers (len, substr, strpos, strrpos)


• Stream Filter stream_filter_append($fp, 'convert.iconv.ISO-2022-JP/EUC-JP')
  

DATABASES

• mysql: Charset and collation on tables and on connection (not the collation). Also don't use mysql - msqli or PDO


• postgresql: pg_set_client_encoding


• sqlite(3): Make sure it was compiled with unicode and intl support

Some other Gotchas

• You cannot use unicode filenames with PHP and windows unless you use a 3rd part extension.


• Send everything in ASCII if you are using exec, proc_open and other command line calls


• Plain text is not plain text, files have encodings


• You can convert files on the fly with the iconv filter

I ll update this answer in case things change features added and so on.

I recently discovered that using strtolower() can cause issues where the data is truncated after a special character.

The solution was to use

mb_strtolower($string, 'UTF-8');

mb_ uses MultiByte. It supports more characters but in general is a little slower.

The only thing I would add to these amazing answers is to emphasize on saving your files in utf8 encoding, i have noticed that browsers accept this property over setting utf8 as your code encoding. Any decent text editor will show you this, for example Notepad++ has a menu option for file enconding, it shows you the current encoding and enables you to change it. For all my php files I use utf8 without BOM.

Sometime ago i had someone ask me to add utf8 support for a php/mysql application designed by someone else, i noticed that all files were encoded in ANSI, so I had to use ICONV to convert all files, change the database tables to use the utf8 charset and utf8_general_ci collate, add 'SET NAMES utf8' to the database abstraction layer after the connection (if using 5.3.6 or earlier otherwise you have to use charset=utf8 in the connection string) and change string functions to use the php multibyte string functions equivalent.

In PHP, you'll need to either use the multibyte functions, or turn on mbstring.func_overload. That way things like strlen will work if you have characters that take more than one byte.

You'll also need to identify the character set of your responses. You can either use AddDefaultCharset, as above, or write PHP code that returns the header. (Or you can add a META tag to your HTML documents.)

I have just went through the same issue and found a good solution at PHP manuals.

I changed all my file encoding to UTF8 then the default encoding on my connection. This solved all the problems.

if (!$mysqli->set_charset("utf8")) {

    printf("Error loading character set utf8: %sn", $mysqli->error);

} else {

   printf("Current character set: %sn", $mysqli->character_set_name());

}

View Source

Unicode support in PHP is still a huge mess. While it's capable of converting an ISO8859 string (which it uses internally) to utf8, it lacks the capability to work with unicode strings natively, which means all the string processing functions will mangle and corrupt your strings. So you have to either use a separate library for proper utf8 support, or rewrite all the string handling functions yourself.

The easy part is just specifying the charset in HTTP headers and in the database and such, but none of that matters if your PHP code doesn't output valid UTF8. That's the hard part, and PHP gives you virtually no help there. (I think PHP6 is supposed to fix the worst of this, but that's still a while away)

The top answer is excellent. Here is what I had to on a regular debian/php/mysql setup:

// storage

// debian. apparently already utf-8



// retrieval

// the mysql database was stored in utf-8, 

// but apparently php was requesting iso. this worked: 

// ***notice "utf8", without dash, this is a mysql encoding***

mysql_set_charset('utf8');



// delivery

// php.ini did not have a default charset, 

// (it was commented out, shared host) and

// no http encoding was specified in the apache headers.

// this made apache send out a utf-8 header

// (and perhaps made php actually send out utf-8)

// ***notice "utf-8", with dash, this is a php encoding***

ini_set('default_charset','utf-8');



// submission

// this worked in all major browsers once apache

// was sending out the utf-8 header. i didnt add

// the accept-charset attribute.



// processing

// changed a few commands in php, like substr,

// to mb_substr

that was all !

If you want MySQL server to decide character set, and not PHP as a client (old behaviour; preferred, in my opinion), try adding skip-character-set-client-handshake to your my.cnf, under [mysqld], and restart mysql.

This may cause troubles in case you're using anything other than UTF8.