PHP i18n

This is a simple i18n class for PHP. Nothing fancy, but fast, because it uses caching and it is easy to use. Try it out!

Some of its features:

• Translation strings in .ini/.properties, .json or .yaml format
• Caching
• Simple API: L::category_stringname
• Built-in support for vsprintf formatting: L::name($par1)
• Automatic user language detection
• Simplicity ;)

Requirements

• Write permissions in cache directory
• PHP 5.2 and above
• PHP SPL extension (installed by default)

Setup

There's a usable example in the example.php file. You just have to follow these easy five steps:

1. Create language files

To use this class, you need to create translation files with your translated strings. They can be .ini/.properties, .json or .yaml files. This could look like this:

lang_en.ini (English)

greeting = "Hello World!"

[category]
somethingother = "Something other..."

lang_de.ini (German)

greeting = "Hallo Welt!"

[category]
somethingother = "Etwas anderes..."

Save both files in the directory you will set in step 4. The files must be named according to the filePath setting, where '{LANGUAGE}' will be replaced by the user's language, e.g. 'en' or 'de'.

2. Include the class

<?php
	require_once 'i18n.class.php';
?>

3. Initialize the class

<?php
	$i18n = new i18n();
?>

4. Set some settings if necessary

The possible settings are:

• Language file path (default: ./lang/lang_{LANGUAGE}.ini)
• Cache file path (default: ./langcache/)
• Preserve language region variants: if set to true, region variants in language code strings such as en-us and en-gb will be preserved, otherwise will be trimmed to en (default: false)
• The fallback language, if no one of the user languages is available (default: en)
• A 'prefix', the compiled class name (default L)
• A forced language, if you want to force a language (default: none)
• The section separator: this is used to seperate the sections in the language class. If you set the separator to _abc_ you could access your localized strings via L::category_abc_stringname if you use categories in your ini. (default: _)
• Merge keys from the fallback language into the current language

<?php
	$i18n->setCachePath('./tmp/cache');
	$i18n->setFilePath('./langfiles/lang/lang_{LANGUAGE}.ini'); // language file path
	$i18n->setLangVariantEnabled(false); // trim region variant in language codes (e.g. en-us -> en)
	$i18n->setFallbackLang('en');
	$i18n->setPrefix('I');
	$i18n->setForcedLang('en'); // force english, even if another user language is available
	$i18n->setSectionSeparator('_');
	$i18n->setMergeFallback(false); // make keys available from the fallback language
?>

Shorthand

There is also a shorthand for that: you can set all settings in the constructor.

<?php
	$i18n = new i18n('lang/lang_{LANGUAGE}.ini', 'langcache/', 'en');
?>

The (all optional) parameters are:

1. the language file path (the ini files)
2. the language cache path
3. fallback language
4. the prefix/compiled class name

5. Call the init() method to load all files and translations

Call the init() file to instruct the class to load the appropriate language file, load the cache file or generate it if it doesn't exist and make the L class available so you can access your localizations.

<?php
	$i18n->init();
?>

6. Use the localizations

To call your localizations, simply use the L class and a class constant for the string.

In this example, we use the translation string seen in step 1.

<?php
	echo L::greeting;
	// If 'en' is applied: 'Hello World'

	echo L::category_somethingother;
	// If 'en' is applied: 'Something other...'

	echo L::last_modified("today");
	// Could be: 'Last modified: today'

	echo L($string);
	// Outputs a dynamically chosen static property

	echo L($string, $args);
	// Same as L::last_modified("today");

?>

As you can see, you can also call the constant as a function. It will be formatted with vsprintf.

Also, like in the two last examples, a helper function with the same name as the class makes it easier to dynamically access the constants if ever needed.

Thats it!

How the user language detection works

This class tries to detect the user's language by trying the following sources in this order:

1. Forced language (if set)
2. GET parameter 'lang' ($_GET['lang'])
3. SESSION parameter 'lang' ($_SESSION['lang'])
4. HTTP_ACCEPT_LANGUAGE (can be multiple languages) ($_SERVER['HTTP_ACCEPT_LANGUAGE'])
5. Fallback language

php-i18n will remove all characters that are not one of the following: A-Z, a-z or 0-9 to prevent arbitrary file inclusion. After that the class searches for the language files. For example, if you set the GET parameter 'lang' to 'en' without a forced language set, the class would try to find the file lang/lang_en.ini (if the setting langFilePath was set to default (lang/lang_{LANGUAGE}.ini)). If this file doesn't exist, php-i18n will try to find the language file for the language defined in the session variable and so on.

How to change this implementation

You can change the user detection by extending the i18n class and overriding the getUserLangs() method:

<?php
	require_once 'i18n.class.php';
	class My_i18n extends i18n {

		public function getUserLangs() {
			$userLangs = new array();

			$userLangs[] = $_GET['language'];

			$userLangs[] = $_SESSION['userlanguage'];

			return $userLangs;
		}

	}

	$i18n = new My_i18n();
	// [...]
?>

This very basic extension only uses the GET parameter 'language' and the session parameter 'userlanguage'. You see that this method must return an array.

Note that this example function is insecure: getUserLangs() also has to escape the results or else i18n will include arbitrary files. The default implementation is safe.

Fork it!

Contributions are always welcome.