By mercutio


2008-11-10 21:04:56 8 Comments

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.

Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?

This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.

14 comments

@castro_pereira 2019-03-24 19:27:24

if you want a mysql solution, I had similar issues with 2 of my projects, after a server migration. After searching and trying a lot of solutions i came across with this one /nothing before this one worked):

mysqli_set_charset($con,"utf8");

After adding this line to my config file everything works fine!

I found this solution https://www.w3schools.com/PHP/func_mysqli_set_charset.asp when i was looking to solve a insert from html query

good luck!

@Abdul Sadik Yalcin 2015-05-05 21:36:17

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: %s\n", $mysqli->error);
} else {
   printf("Current character set: %s\n", $mysqli->character_set_name());
}

View Source

@Funk Forty Niner 2017-01-21 14:16:41

I spent an hour trying to figure out an encoding problem on a page I'm working on and I'm usually pretty good at figuring out stuff. I always consult this page and your answer helped me a lot. Got my upvote. In my case, set_charset('utf8mb4') did not work but >set_charset("utf8") did and that wasn't actually shown in the other answers.

@Martin Hennings 2018-04-24 10:09:28

@FunkFortyNiner Beware: set_charset("utf8") may work but will behave differently (see the remarks about the difference between utf8 and utf8mb4 and the mysql version history). Use utf8 if you have to AND ONLY if you know what you're doing!

@Notflip 2014-01-13 09:37:02

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.

@Puerto AGP 2014-09-10 03:39:22

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.

@chazomaticus 2008-11-10 21:43:05

Data Storage:

  • Specify the utf8mb4 character set on all tables and text columns in your database. This makes MySQL physically store and retrieve values encoded natively in UTF-8. Note that MySQL will implicitly use utf8mb4 encoding if a utf8mb4_* collation is specified (without any explicit character set).

  • In older versions of MySQL (< 5.5.3), you'll unfortunately be forced to use simply utf8, which only supports a subset of Unicode characters. I wish I were kidding.

Data Access:

  • In your application code (e.g. PHP), in whatever DB access method you use, you'll need to set the connection charset to utf8mb4. This way, MySQL does no conversion from its native UTF-8 when it hands data off to your application and vice versa.

  • Some drivers provide their own mechanism for configuring the connection character set, which both updates its own internal state and informs MySQL of the encoding to be used on the connection—this is usually the preferred approach. In PHP:

    • If you're using the PDO abstraction layer with PHP ≥ 5.3.6, you can specify charset in the DSN:

      $dbh = new PDO('mysql:charset=utf8mb4');
      
    • If you're using mysqli, you can call set_charset():

      $mysqli->set_charset('utf8mb4');       // object oriented style
      mysqli_set_charset($link, 'utf8mb4');  // procedural style
      
    • If you're stuck with plain mysql but happen to be running PHP ≥ 5.2.3, you can call mysql_set_charset.

  • If the driver does not provide its own mechanism for setting the connection character set, you may have to issue a query to tell MySQL how your application expects data on the connection to be encoded: SET NAMES 'utf8mb4'.

  • The same consideration regarding utf8mb4/utf8 applies as above.

Output:

  • If your application transmits text to other systems, they will also need to be informed of the character encoding. With web applications, the browser must be informed of the encoding in which data is sent (through HTTP response headers or HTML metadata).

  • In PHP, you can use the default_charset php.ini option, or manually issue the Content-Type MIME header yourself, which is just more work but has the same effect.

Input:

  • Unfortunately, you should verify every received string as being valid UTF-8 before you try to store it or use it anywhere. PHP's mb_check_encoding() does the trick, but you have to use it religiously. There's really no way around this, as malicious clients can submit data in whatever encoding they want, and I haven't found a trick to get PHP to do this for you reliably.

  • From my reading of the current HTML spec, the following sub-bullets are not necessary or even valid anymore for modern HTML. My understanding is that browsers will work with and submit data in the character set specified for the document. However, if you're targeting older versions of HTML (XHTML, HTML4, etc.), these points may still be useful:

    • For HTML before HTML5 only: you want all data sent to you by browsers to be in UTF-8. Unfortunately, if you go by the the only way to reliably do this is add the accept-charset attribute to all your <form> tags: <form ... accept-charset="UTF-8">.
    • For HTML before HTML5 only: note that the W3C HTML spec says that clients "should" default to sending forms back to the server in whatever charset the server served, but this is apparently only a recommendation, hence the need for being explicit on every single <form> tag.

Other Code Considerations:

  • Obviously enough, all files you'll be serving (PHP, HTML, JavaScript, etc.) should be encoded in valid UTF-8.

  • You need to make sure that every time you process a UTF-8 string, you do so safely. This is, unfortunately, the hard part. You'll probably want to make extensive use of PHP's mbstring extension.

  • PHP's built-in string operations are not by default UTF-8 safe. There are some things you can safely do with normal PHP string operations (like concatenation), but for most things you should use the equivalent mbstring function.

  • To know what you're doing (read: not mess it up), you really need to know UTF-8 and how it works on the lowest possible level. Check out any of the links from utf8.com for some good resources to learn everything you need to know.

@troelskn 2008-11-10 21:47:51

collation is not the same as encoding. Be sure to set the encoding to utf8, in your database. Collation is less important.

@chazomaticus 2008-11-10 21:49:51

It's my understanding that if you specify the collation as utf8_*, it automatically encodes as utf8 as well. Is this wrong?

@chazomaticus 2008-11-10 23:01:19

I'm not wrong: COLLATE implies CHARACTER SET. See e.g. dev.mysql.com/doc/refman/5.0/en/charset-database.html.

@bobince 2010-01-15 01:28:24

The ‘submit forms in the same encoding as the page they came from’ recommendation does work in every browser since Unicode was invented. accept-charset="UTF-8", unfortunately, does not. In IE, this will make submissions use UTF-8 not as a replacement encoding, but as a backup encoding, for fields that can't be encoded in the primary (page) encoding. And it doesn't tell you which encoding it used, so you can't recover the information reliably. On pages that are already UTF-8 it has no effect; on pages with other charsets it is actively harmful. Avoid.

@VolkerK 2010-01-30 15:28:36

Regarding SET NAMES please have a read of ilia.ws/archives/… and docs.php.net/mysql_set_charset (if you're using php-mysql and not prepared statements)

@Ja͢ck 2012-10-22 03:35:21

Consider adding PDO examples for setting the character set as well.

@R. Martinho Fernandes 2013-04-09 09:21:04

Note that MySQL does not speak the same language as everyone else. When MySQL says "utf8" it really means "some weirdly retarded variant of UTF-8 that is limited to three bytes for god knows what ridiculous reason". If you really want UTF-8 you should tell MySQL that you want this weird thing MySQL likes to call utf8mb4. Don't bother saving on the "WTF!"s.

@Jago 2014-07-17 05:04:30

The key point of the whole answer is to use $mysqli->set_charset('utf8mb4'); or whatever other CHARSET/COLLATION you are using on your tables.

@David 2015-01-13 11:43:51

I guess the utf8mb4 is there because the CHAR type needs to allocate memory for the (number of chars) X (the maximum size of a single char). It seems that they considered in the past that this maximum size for UTF8 was 3 bytes. If they change it now then the text could not fit into the field if the server is not updated.

@Wes 2015-11-26 12:37:17

phpwact.org/php/i18n/utf-8 useful resource about php string functions

@vy32 2015-12-28 18:13:38

UTF-8 can encode all Unicode characters. It's only MySQL's UTF-8 is limited to 3 characters.

@Basil Musa 2016-01-16 11:41:51

For php string handling, save yourself the headache and use Patchwork UTF-8 github.com/tchwork/utf8

@rybo111 2016-11-14 16:01:39

Related note: utf8mb4 table keys are 250 characters or less, as MySQL limits to 1000 bytes. So, no more VARCHAR(255) (for keys, at least).

@Markus AO 2017-01-05 22:57:05

One more note, under "Input" and verifying source strings: You should, of course, also verify that a .sql dump file you're importing into MySQL is a valid UTF-8 file. Not uncommon to muck up a database with non-UTF-8 exported or imported dumps (or messed up by text editors).

@Petay87 2017-12-14 09:49:56

This answer helped me so much BUT I also found that in my case I needed to add JSON_UNESCAPED_UNICODE to my PHP json_encode when passing the DB query results back via ajax.

@Nikola Tulimirovic 2015-02-11 23:52:55

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.

@Jimmy Kane 2014-01-27 09:16:00

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.

@Alexander Yancharuk 2014-02-16 17:54:56

Yes, right. Mysqli and PDO can use their native drivers. Also they can use mysqlnd driver if you will compile php with --with-mysqli=mysqlnd --with-pdo-mysql=mysqlnd options.

@jalf 2008-11-10 21:48:07

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)

@Brad F Jacobs 2012-09-11 15:40:11

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.

@Marten Koetsier 2015-08-13 13:55:16

Looking for this a bit further, this is only necessary for PHP versions prior to 5.3.6. See also: http://stackoverflow.com/a/4361485/2286722 (although they use a separate $dbh->exec("set names utf8");; I do prefer the method presented here). Btw. there is also a similar note on this as a comment in the PHP manual: php.net/manual/en/pdo.construct.php#96325.

@JDelage 2012-02-23 22:20:22

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");.

@commonpike 2011-01-14 16:13:18

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 !

@mercator 2008-11-12 19:27:00

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:

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

@oliver 2008-11-20 17:47:32

Shouldn't it also be possible to specify the charset in the HTTP headers? Probably needs some config option for the webserver...

@user42092 2008-12-02 01:49:26

@oliver: Yes you can send it in the HTTP header, but it's better to send it in the content because if the client saves the file, it'll always save the meta tag. A HTTP header is likely to just disappear unless the browser is smart enough to copy it into a meta tag in the saved file.

@alex 2010-04-20 08:55:18

Also, make sure that line is the first child of head element (before any Unicode stuff). The browser may reinterpret the page after hitting that meta element described above.

@Mirich 2018-09-10 12:48:22

@mercator, hi dude, I am beginner in web development and faced the same issue, while trying to change language of formated date time I faced this issue 10 �������� 2018, I am using utf-8 in an html and I was suggested to make database and browser compatible with utf-8 so I can solve my problem. Please can you help me. I hope for your attention

@Mirich 2018-09-10 12:48:51

@mercator, I am using PHP Laravel

@chroder 2008-11-10 21:30:36

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.

@Anthony Rutledge 2015-12-21 20:52:27

Set the overload setting in the php.ini. It helps when using multi-byte strings.

@JW. 2008-11-10 21:29:21

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.)

@Simon East 2014-01-15 04:56:15

Great tip about the func_overload setting - allows for minimal modification to existing code.

@JW. 2014-01-15 18:18:29

Just be careful -- some code might actually be relying on the one-byte-per-character nature of the standard string functions.

@Simba 2017-02-07 13:08:02

Important to note that the mbstring.func_overload feature is being deprecated as of PHP 7.2, due to the issues noted in @JW's comment above. So the best advice is: Yes you should definitely use the mbstring functions, but don't use the overload feature to get the standard functions to work as multibyte.

Related Questions

Sponsored Content

16 Answered Questions

[SOLVED] Best way to convert text files between character sets?

41 Answered Questions

[SOLVED] How do I find all files containing specific text on Linux?

20 Answered Questions

11 Answered Questions

[SOLVED] How to change the default encoding to UTF-8 for Apache?

11 Answered Questions

[SOLVED] What is the best collation to use for MySQL with PHP?

7 Answered Questions

[SOLVED] UTF-8 problems PHP/MySQL

  • 2011-01-07 08:25:10
  • Mikkel
  • 30178 View
  • 11 Score
  • 7 Answer
  • Tags:   php mysql utf-8

1 Answered Questions

[SOLVED] Encoding problems between UTF-8 and ISO-8859-1 in LAMP stack

1 Answered Questions

[SOLVED] Ajax, Request Header UTF-8 to ISO Charset

1 Answered Questions

[SOLVED] Apache's default encoding is ISO-8859-1 but websites are UTF-8?

1 Answered Questions

[SOLVED] Why are Scandinavian characters converted to UTF-8?

  • 2010-09-26 06:48:03
  • Kristoffer Bohmann
  • 1437 View
  • 1 Score
  • 1 Answer
  • Tags:   php apache utf-8

Sponsored Content