Solve a page encoding problem

This guide is for developers and webmasters experiencing issues displaying special characters (such as accents, Arabic characters, Chinese characters, emojis, etc.), whether on an Infomaniak website or in its database.

Preamble

Common causes of incorrectly displayed characters that appear instead of special characters or emojis like ??:
- PHP connection in utf8 instead of utf8mb4
- MySQL table or column in latin1 or utf8 instead of utf8mb4
- SQL file encoded differently from the import parameter
- HTML/CSS/JS files improperly encoded
- Missing or incorrect charset declaration on the HTML, PHP, or HTTP side
Common solutions:
- Use utf8mb4 everywhere: database, connections, tables, columns, files, headers
- Validate the encoding of all files and dumps
- Test the display of emojis, accents, and other multilingual characters
Also refer to this other guide to force another encoding when connecting to a MySQL database.

Use a text editor that supports saving in UTF-8 without BOM (Visual Studio Code, Sublime Text, Notepad++...)

1. Use UTF-8 or UTF-8MB4 everywhere

The utf8 encoding of MySQL does not support characters on 4 bytes, like emojis. These will display as ??. Therefore, you should use utf8mb4, which is a true complete implementation of UTF-8.

2. HTML – Correct encoding declaration

In the <head> of your HTML pages:

<meta charset="UTF-8">

Make sure that CSS/JS files are also saved in UTF-8 (without BOM).

3. PHP – Force UTF-8 or UTF-8MB4

a) HTTP headers

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

b) MySQL Connection (MySQL API)

$connection = mysql_connect($host, $user, $pass);
mysql_set_charset('utf8mb4', $connection);

c) PDO Connection

 $dsn = "mysql:host=localhost;dbname=ma_base;charset=utf8mb4";
$pdo = new PDO($dsn, $user, $pass, [
    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
]);

4. MySQL database

a) Configuration in phpMyAdmin

Databases, tables, and columns should be in utf8mb4_unicode_ci or utf8mb4_general_ci.
In the Operations tab, select utf8mb4_unicode_ci for the collation.

b) Useful SQL commands

ALTER DATABASE ma_base CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci;
ALTER TABLE ma_table CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

c) After the PHP connection

mysqli_query($conn, "SET NAMES 'utf8mb4'");
mysqli_query($conn, "SET CHARACTER SET 'utf8mb4'");

5. .user.ini / .htaccess file

To force encoding on the server side (Apache):

AddDefaultCharset utf-8
Header set Content-Type "text/html; charset=utf-8"
# Pour PHP
php_value default_charset UTF-8
php_value mbstring.internal_encoding UTF-8

6. Import / export of SQL dumps

Errors such as é becoming ? or an emoji ☺ becoming ?? often stem from encoding misalignment.

Check the encoding of the SQL file before import. Use iconv if necessary:

iconv -f ISO-8859-1 -t UTF-8 dump.sql > dump_utf8.sql

In phpMyAdmin, specify the import encoding (for example UTF-8, UTF-8MB4 or latin1 depending on the file).

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