README

Translation API for PHP using Gettext MO files.

Features

• All strings are stored in memory for fast lookup
• Fast loading of MO files
• Low level API for reading MO files
• Emulation of Gettext API
• No use of eval() for plural equation

Limitations

• Default InMemoryCache not suitable for huge MO files which you don't want to store in memory
• Input and output encoding has to match (preferably UTF-8)

Installation

Please use Composer to install:

composer require phpmyadmin/motranslator

Documentation

The API documentation is available at https://develdocs.phpmyadmin.net/motranslator/.

Object API usage

// Create loader object
$loader = new PhpMyAdmin\MoTranslator\Loader();

// Set locale
$loader->setlocale('cs');

// Set default text domain
$loader->textdomain('domain');

// Set path where to look for a domain
$loader->bindtextdomain('domain', __DIR__ . '/data/locale/');

// Get translator
$translator = $loader->getTranslator();

// Now you can use Translator API (see below)

Low level API usage

// Directly load the mo file
// You can use null to not load a file and the use a setter to set the translations
$cache = new PhpMyAdmin\MoTranslator\Cache\InMemoryCache(new PhpMyAdmin\MoTranslator\MoParser('./path/to/file.mo'));
$translator = new PhpMyAdmin\MoTranslator\Translator($cache);

// Now you can use Translator API (see below)

Translator API usage

// Translate string
echo $translator->gettext('String');

// Translate plural string
echo $translator->ngettext('String', 'Plural string', $count);

// Translate string with context
echo $translator->pgettext('Context', 'String');

// Translate plural string with context
echo $translator->npgettext('Context', 'String', 'Plural string', $count);

// Get the translations
echo $translator->getTranslations();

// All getters and setters below are more to be used if you are using a manual loading mode
// Example: $translator = new PhpMyAdmin\MoTranslator\Translator(null);

// Set a translation
echo $translator->setTranslation('Test', 'Translation for "Test" key');

// Set translations
echo $translator->setTranslations([
  'Test' => 'Translation for "Test" key',
  'Test 2' => 'Translation for "Test 2" key',
]);

// Use the translation
echo $translator->gettext('Test 2'); // -> Translation for "Test 2" key

Gettext compatibility usage

// Load compatibility layer
PhpMyAdmin\MoTranslator\Loader::loadFunctions();

// Configure
_setlocale(LC_MESSAGES, 'cs');
_textdomain('phpmyadmin');
_bindtextdomain('phpmyadmin', __DIR__ . '/data/locale/');
_bind_textdomain_codeset('phpmyadmin', 'UTF-8');

// Use functions
echo _gettext('Type');
echo __('Type');

// It also support other Gettext functions
_dnpgettext($domain, $msgctxt, $msgid, $msgidPlural, $number);
_dngettext($domain, $msgid, $msgidPlural, $number);
_npgettext($msgctxt, $msgid, $msgidPlural, $number);
_ngettext($msgid, $msgidPlural, $number);
_dpgettext($domain, $msgctxt, $msgid);
_dgettext($domain, $msgid);
_pgettext($msgctxt, $msgid);

Using APCu-backed cache

If you have the APCu extension installed you can use it for storing the translation cache. The .mo file will then only be loaded once and all processes will share the same cache, reducing memory usage and resulting in performance comparable to the native gettext extension.

If you are using Loader, pass it an ApcuCacheFactory before getting the translator instance:

PhpMyAdmin\MoTranslator\Loader::setCacheFactory(
    new PhpMyAdmin\MoTranslator\Cache\ApcuCacheFactory()
);
$loader = new PhpMyAdmin\MoTranslator\Loader();

// Proceed as before 

If you are using the low level API, instantiate the ApcuCache directly:

$cache = new PhpMyAdmin\MoTranslator\Cache\ApcuCache(
    new PhpMyAdmin\MoTranslator\MoParser('./path/to/file.mo'),
    'de_DE',     // the locale
    'phpmyadmin' // the domain
);
$translator = new PhpMyAdmin\MoTranslator\Translator($cache);

// Proceed as before

By default, APCu will cache the translations until next server restart and prefix the cache entries with mo_ to avoid clashes with other cache entries. You can control this behaviour by passing $ttl and $prefix arguments, either to the ApcuCacheFactory or when instantiating ApcuCache:

PhpMyAdmin\MoTranslator\Loader::setCacheFactory(
    new PhpMyAdmin\MoTranslator\Cache\ApcuCacheFactory(
        3600,     // cache for 1 hour
        true,     // reload on cache miss
        'custom_' // custom prefix for cache entries
    )
);
$loader = new PhpMyAdmin\MoTranslator\Loader();

// or...

$cache = new PhpMyAdmin\MoTranslator\Cache\ApcuCache(
    new PhpMyAdmin\MoTranslator\MoParser('./path/to/file.mo'),
    'de_DE',
    'phpmyadmin',
    3600,     // cache for 1 hour
    true,     // reload on cache miss
    'custom_' // custom prefix for cache entries
);
$translator = new PhpMyAdmin\MoTranslator\Translator($cache);

If you receive updated translation files you can load them without restarting the server using the low-level API:

$parser = new PhpMyAdmin\MoTranslator\MoParser('./path/to/file.mo');
$cache = new PhpMyAdmin\MoTranslator\Cache\ApcuCache($parser, 'de_DE', 'phpmyadmin');
$parser->parseIntoCache($cache);

You should ensure APCu has enough memory to store all your translations, along with any other entries you use it for. If an entry is evicted from cache, the .mo file will be re-parsed, impacting performance. See the apc.shm_size and apc.shm_segments documentation and monitor cache usage when first rolling out.

If your .mo files are missing lots of translations, the first time a missing entry is requested the .mo file will be re-parsed. Again, this will impact performance until all the missing entries are hit once. You can turn off this behaviour by setting the $reloadOnMiss argument to false. If you do this it is critical that APCu has enough memory, or users will see untranslated text when entries are evicted.

History

This library is based on php-gettext. It adds some performance improvements and ability to install using Composer.

Motivation

Motivation for this library includes:

• The php-gettext library is not maintained anymore
• It doesn't work with recent PHP version (phpMyAdmin has patched version)
• It relies on eval() function for plural equations what can have severe security implications, see CVE-2016-6175
• It's not possible to install it using Composer
• There was place for performance improvements in the library

Why not to use native gettext in PHP?

We've tried that, but it's not a viable solution:

• You can not use locales not known to system, what is something you can not control from web application. This gets even more tricky with minimalist virtualisation containers.
• Changing the MO file usually leads to PHP segmentation fault. It (or rather Gettext library) caches headers of MO file and if it's content is changed (for example new version is uploaded to server) it tries to access new data with old references. This is bug known for ages: https://bugs.php.net/bug.php?id=45943

Why use Gettext and not JSON, YAML or whatever?

We want translators to be able to use their favorite tools and we want us to be able to use wide range of tools available with Gettext as well such as web based translation using Weblate. Using custom format usually adds another barrier for translators and we want to make it easy for them to contribute.