Việt hóa cho WordPress bằng cách dùng filter

Đại đa số người dùng ở Việt Nam đều dùng ngôn ngữ là Tiếng Việt để viết bài trên WordPress, để Việt hóa cho WordPress thì có nhiều cách khác nhau, bạn có thể chuyển toàn bộ ngôn ngữ sang sử dụng Tiếng Việt, cũng có thể dịch ở bên ngoài front-end, còn bên trong bảng điều khiển (back-end hay dashboard) thì dùng Tiếng Anh. Bài viết này mình sẽ hướng dẫn cho các bạn cách dịch ngôn ngữ sang Tiếng Việt bằng việc sử dụng các bộ lọc của WordPress.

Tiếng Việt cho WordPress

Đương nhiên là cách này phải đụng tới code PHP, do vậy để dễ dàng thực hiện được thì bạn phải biết một chút về code mới được. Nếu bạn không biết code thì cũng không sao vì lập trình là cóp dán mà, bạn chỉ việc sao chép và bỏ vào tập tin functions.php của giao diện là có thể hoạt động.

Các bài viết có liên quan đến ngôn ngữ

Danh sách các bộ lọc ngôn ngữ trên WordPress:

  • gettext: Sử dụng cho các hàm _e, __
  • gettext_with_context: sử dụng cho hàm _x, _ex
  • ngettext: sử dụng cho hàm _n
  • ngettext_with_context: sử dụng cho hàm _nx

Bạn có thể tham khảo thêm các hàm ngôn ngữ của WordPress trên trang L10n. Hoặc bạn có thể xem nội dung của tập tin l10n.php nằm trong bộ nhân của WordPress.

<?php
/**
 * WordPress Translation API
 *
 * @package WordPress
 * @subpackage i18n
 */

/**
 * Get the current locale.
 *
 * If the locale is set, then it will filter the locale in the 'locale' filter
 * hook and return the value.
 *
 * If the locale is not set already, then the WPLANG constant is used if it is
 * defined. Then it is filtered through the 'locale' filter hook and the value
 * for the locale global set and the locale is returned.
 *
 * The process to get the locale should only be done once, but the locale will
 * always be filtered using the 'locale' hook.
 *
 * @since 1.5.0
 *
 * @return string The locale of the blog or from the 'locale' hook.
 */
function get_locale() {
	global $locale, $wp_local_package;

	if ( isset( $locale ) ) {
		/**
		 * Filter WordPress install's locale ID.
		 *
		 * @since 1.5.0
		 *
		 * @param string $locale The locale ID.
		 */
		return apply_filters( 'locale', $locale );
	}

	if ( isset( $wp_local_package ) ) {
		$locale = $wp_local_package;
	}

	// WPLANG was defined in wp-config.
	if ( defined( 'WPLANG' ) ) {
		$locale = WPLANG;
	}

	// If multisite, check options.
	if ( is_multisite() ) {
		// Don't check blog option when installing.
		if ( defined( 'WP_INSTALLING' ) || ( false === $ms_locale = get_option( 'WPLANG' ) ) ) {
			$ms_locale = get_site_option( 'WPLANG' );
		}

		if ( $ms_locale !== false ) {
			$locale = $ms_locale;
		}
	} else {
		$db_locale = get_option( 'WPLANG' );
		if ( $db_locale !== false ) {
			$locale = $db_locale;
		}
	}

	if ( empty( $locale ) ) {
		$locale = 'en_US';
	}

	/** This filter is documented in wp-includes/l10n.php */
	return apply_filters( 'locale', $locale );
}

/**
 * Retrieve the translation of $text.
 *
 * If there is no translation, or the text domain isn't loaded, the original text is returned.
 *
 * *Note:* Don't use {@see translate()} directly, use `{@see __()} or related functions.
 *
 * @since 2.2.0
 *
 * @param string $text   Text to translate.
 * @param string $domain Optional. Text domain. Unique identifier for retrieving translated strings.
 * @return string Translated text
 */
function translate( $text, $domain = 'default' ) {
	$translations = get_translations_for_domain( $domain );
	$translations = $translations->translate( $text );

	/**
	 * Filter text with its translation.
	 *
	 * @since 2.0.11
	 *
	 * @param string $translations Translated text.
	 * @param string $text         Text to translate.
	 * @param string $domain       Text domain. Unique identifier for retrieving translated strings.
	 */
	return apply_filters( 'gettext', $translations, $text, $domain );
}

/**
 * Remove last item on a pipe-delimited string.
 *
 * Meant for removing the last item in a string, such as 'Role name|User role'. The original
 * string will be returned if no pipe '|' characters are found in the string.
 *
 * @since 2.8.0
 *
 * @param string $string A pipe-delimited string.
 * @return string Either $string or everything before the last pipe.
 */
function before_last_bar( $string ) {
	$last_bar = strrpos( $string, '|' );
	if ( false == $last_bar )
		return $string;
	else
		return substr( $string, 0, $last_bar );
}

/**
 * Retrieve the translation of $text in the context defined in $context.
 *
 * If there is no translation, or the text domain isn't loaded the original
 * text is returned.
 *
 * @since 2.8.0
 *
 * @param string $text    Text to translate.
 * @param string $context Context information for the translators.
 * @param string $domain  Optional. Text domain. Unique identifier for retrieving translated strings.
 * @return string Translated text on success, original text on failure.
 */
function translate_with_gettext_context( $text, $context, $domain = 'default' ) {
	$translations = get_translations_for_domain( $domain );
	$translations = $translations->translate( $text, $context );
	/**
	 * Filter text with its translation based on context information.
	 *
	 * @since 2.8.0
	 *
	 * @param string $translations Translated text.
	 * @param string $text         Text to translate.
	 * @param string $context      Context information for the translators.
	 * @param string $domain       Text domain. Unique identifier for retrieving translated strings.
	 */
	return apply_filters( 'gettext_with_context', $translations, $text, $context, $domain );
}

/**
 * Retrieve the translation of $text. If there is no translation,
 * or the text domain isn't loaded, the original text is returned.
 *
 * @since 2.1.0
 *
 * @param string $text   Text to translate.
 * @param string $domain Optional. Text domain. Unique identifier for retrieving translated strings.
 * @return string Translated text.
 */
function __( $text, $domain = 'default' ) {
	return translate( $text, $domain );
}

/**
 * Retrieve the translation of $text and escapes it for safe use in an attribute.
 *
 * If there is no translation, or the text domain isn't loaded, the original text is returned.
 *
 * @since 2.8.0
 *
 * @param string $text   Text to translate.
 * @param string $domain Optional. Text domain. Unique identifier for retrieving translated strings.
 * @return string Translated text on success, original text on failure.
 */
function esc_attr__( $text, $domain = 'default' ) {
	return esc_attr( translate( $text, $domain ) );
}

/**
 * Retrieve the translation of $text and escapes it for safe use in HTML output.
 *
 * If there is no translation, or the text domain isn't loaded, the original text is returned.
 *
 * @since 2.8.0
 *
 * @param string $text   Text to translate.
 * @param string $domain Optional. Text domain. Unique identifier for retrieving translated strings.
 * @return string Translated text
 */
function esc_html__( $text, $domain = 'default' ) {
	return esc_html( translate( $text, $domain ) );
}

/**
 * Display translated text.
 *
 * @since 1.2.0
 *
 * @param string $text   Text to translate.
 * @param string $domain Optional. Text domain. Unique identifier for retrieving translated strings.
 */
function _e( $text, $domain = 'default' ) {
	echo translate( $text, $domain );
}

/**
 * Display translated text that has been escaped for safe use in an attribute.
 *
 * @since 2.8.0
 *
 * @param string $text   Text to translate.
 * @param string $domain Optional. Text domain. Unique identifier for retrieving translated strings.
 */
function esc_attr_e( $text, $domain = 'default' ) {
	echo esc_attr( translate( $text, $domain ) );
}

/**
 * Display translated text that has been escaped for safe use in HTML output.
 *
 * @since 2.8.0
 *
 * @param string $text   Text to translate.
 * @param string $domain Optional. Text domain. Unique identifier for retrieving translated strings.
 */
function esc_html_e( $text, $domain = 'default' ) {
	echo esc_html( translate( $text, $domain ) );
}

/**
 * Retrieve translated string with gettext context.
 *
 * Quite a few times, there will be collisions with similar translatable text
 * found in more than two places, but with different translated context.
 *
 * By including the context in the pot file, translators can translate the two
 * strings differently.
 *
 * @since 2.8.0
 *
 * @param string $text    Text to translate.
 * @param string $context Context information for the translators.
 * @param string $domain  Optional. Text domain. Unique identifier for retrieving translated strings.
 * @return string Translated context string without pipe.
 */
function _x( $text, $context, $domain = 'default' ) {
	return translate_with_gettext_context( $text, $context, $domain );
}

/**
 * Display translated string with gettext context.
 *
 * @since 3.0.0
 *
 * @param string $text    Text to translate.
 * @param string $context Context information for the translators.
 * @param string $domain  Optional. Text domain. Unique identifier for retrieving translated strings.
 * @return string Translated context string without pipe.
 */
function _ex( $text, $context, $domain = 'default' ) {
	echo _x( $text, $context, $domain );
}

/**
 * Translate string with gettext context, and escapes it for safe use in an attribute.
 *
 * @since 2.8.0
 *
 * @param string $text    Text to translate.
 * @param string $context Context information for the translators.
 * @param string $domain  Optional. Text domain. Unique identifier for retrieving translated strings.
 * @return string Translated text
 */
function esc_attr_x( $text, $context, $domain = 'default' ) {
	return esc_attr( translate_with_gettext_context( $text, $context, $domain ) );
}

/**
 * Translate string with gettext context, and escapes it for safe use in HTML output.
 *
 * @since 2.9.0
 *
 * @param string $text    Text to translate.
 * @param string $context Context information for the translators.
 * @param string $domain  Optional. Text domain. Unique identifier for retrieving translated strings.
 * @return string Translated text.
 */
function esc_html_x( $text, $context, $domain = 'default' ) {
	return esc_html( translate_with_gettext_context( $text, $context, $domain ) );
}

/**
 * Retrieve the plural or single form based on the supplied amount.
 *
 * If the text domain is not set in the $l10n list, then a comparison will be made
 * and either $plural or $single parameters returned.
 *
 * If the text domain does exist, then the parameters $single, $plural, and $number
 * will first be passed to the text domain's ngettext method. Then it will be passed
 * to the 'ngettext' filter hook along with the same parameters. The expected
 * type will be a string.
 *
 * @since 2.8.0
 *
 * @param string $single The text that will be used if $number is 1.
 * @param string $plural The text that will be used if $number is not 1.
 * @param int    $number The number to compare against to use either $single or $plural.
 * @param string $domain Optional. Text domain. Unique identifier for retrieving translated strings.
 * @return string Either $single or $plural translated text.
 */
function _n( $single, $plural, $number, $domain = 'default' ) {
	$translations = get_translations_for_domain( $domain );
	$translation = $translations->translate_plural( $single, $plural, $number );
	/**
	 * Filter text with its translation when plural option is available.
	 *
	 * @since 2.2.0
	 *
	 * @param string $translation Translated text.
	 * @param string $single      The text that will be used if $number is 1.
	 * @param string $plural      The text that will be used if $number is not 1.
	 * @param string $number      The number to compare against to use either $single or $plural.
	 * @param string $domain      Text domain. Unique identifier for retrieving translated strings.
	 */
	return apply_filters( 'ngettext', $translation, $single, $plural, $number, $domain );
}

/**
 * Retrieve the plural or single form based on the supplied amount with gettext context.
 *
 * This is a hybrid of _n() and _x(). It supports contexts and plurals.
 *
 * @since 2.8.0
 *
 * @param string $single  The text that will be used if $number is 1.
 * @param string $plural  The text that will be used if $number is not 1.
 * @param int    $number  The number to compare against to use either $single or $plural.
 * @param string $context Context information for the translators.
 * @param string $domain  Optional. Text domain. Unique identifier for retrieving translated strings.
 * @return string Either $single or $plural translated text with context.
 */
function _nx($single, $plural, $number, $context, $domain = 'default') {
	$translations = get_translations_for_domain( $domain );
	$translation = $translations->translate_plural( $single, $plural, $number, $context );
	/**
	 * Filter text with its translation while plural option and context are available.
	 *
	 * @since 2.8.0
	 *
	 * @param string $translation Translated text.
	 * @param string $single      The text that will be used if $number is 1.
	 * @param string $plural      The text that will be used if $number is not 1.
	 * @param string $number      The number to compare against to use either $single or $plural.
	 * @param string $context     Context information for the translators.
	 * @param string $domain      Text domain. Unique identifier for retrieving translated strings.
	 */
	return apply_filters( 'ngettext_with_context', $translation, $single, $plural, $number, $context, $domain );
}

/**
 * Register plural strings in POT file, but don't translate them.
 *
 * Used when you want to keep structures with translatable plural
 * strings and use them later.
 *
 * Example:
 *
 *     $messages = array(
 *      	'post' => _n_noop( '%s post', '%s posts' ),
 *      	'page' => _n_noop( '%s pages', '%s pages' ),
 *     );
 *     ...
 *     $message = $messages[ $type ];
 *     $usable_text = sprintf( translate_nooped_plural( $message, $count ), $count );
 *
 * @since 2.5.0
 *
 * @param string $singular Single form to be i18ned.
 * @param string $plural   Plural form to be i18ned.
 * @param string $domain   Optional. Text domain. Unique identifier for retrieving translated strings.
 * @return array array($singular, $plural)
 */
function _n_noop( $singular, $plural, $domain = null ) {
	return array( 0 => $singular, 1 => $plural, 'singular' => $singular, 'plural' => $plural, 'context' => null, 'domain' => $domain );
}

/**
 * Register plural strings with context in POT file, but don't translate them.
 *
 * @since 2.8.0
 * @param string $singular
 * @param string $plural
 * @param string $context
 * @param string|null $domain
 * @return array
 */
function _nx_noop( $singular, $plural, $context, $domain = null ) {
	return array( 0 => $singular, 1 => $plural, 2 => $context, 'singular' => $singular, 'plural' => $plural, 'context' => $context, 'domain' => $domain );
}

/**
 * Translate the result of _n_noop() or _nx_noop().
 *
 * @since 3.1.0
 *
 * @param array  $nooped_plural Array with singular, plural and context keys, usually the result of _n_noop() or _nx_noop()
 * @param int    $count         Number of objects
 * @param string $domain        Optional. Text domain. Unique identifier for retrieving translated strings. If $nooped_plural contains
 *                              a text domain passed to _n_noop() or _nx_noop(), it will override this value.
 * @return string Either $single or $plural translated text.
 */
function translate_nooped_plural( $nooped_plural, $count, $domain = 'default' ) {
	if ( $nooped_plural['domain'] )
		$domain = $nooped_plural['domain'];

	if ( $nooped_plural['context'] )
		return _nx( $nooped_plural['singular'], $nooped_plural['plural'], $count, $nooped_plural['context'], $domain );
	else
		return _n( $nooped_plural['singular'], $nooped_plural['plural'], $count, $domain );
}

/**
 * Load a .mo file into the text domain $domain.
 *
 * If the text domain already exists, the translations will be merged. If both
 * sets have the same string, the translation from the original value will be taken.
 *
 * On success, the .mo file will be placed in the $l10n global by $domain
 * and will be a MO object.
 *
 * @since 1.5.0
 *
 * @param string $domain Text domain. Unique identifier for retrieving translated strings.
 * @param string $mofile Path to the .mo file.
 * @return bool True on success, false on failure.
 */
function load_textdomain( $domain, $mofile ) {
	global $l10n;

	/**
	 * Filter text domain and/or MO file path for loading translations.
	 *
	 * @since 2.9.0
	 *
	 * @param bool   $override Whether to override the text domain. Default false.
	 * @param string $domain   Text domain. Unique identifier for retrieving translated strings.
	 * @param string $mofile   Path to the MO file.
	 */
	$plugin_override = apply_filters( 'override_load_textdomain', false, $domain, $mofile );

	if ( true == $plugin_override ) {
		return true;
	}

	/**
	 * Fires before the MO translation file is loaded.
	 *
	 * @since 2.9.0
	 *
	 * @param string $domain Text domain. Unique identifier for retrieving translated strings.
	 * @param string $mofile Path to the .mo file.
	 */
	do_action( 'load_textdomain', $domain, $mofile );

	/**
	 * Filter MO file path for loading translations for a specific text domain.
	 *
	 * @since 2.9.0
	 *
	 * @param string $mofile Path to the MO file.
	 * @param string $domain Text domain. Unique identifier for retrieving translated strings.
	 */
	$mofile = apply_filters( 'load_textdomain_mofile', $mofile, $domain );

	if ( !is_readable( $mofile ) ) return false;

	$mo = new MO();
	if ( !$mo->import_from_file( $mofile ) ) return false;

	if ( isset( $l10n[$domain] ) )
		$mo->merge_with( $l10n[$domain] );

	$l10n[$domain] = &$mo;

	return true;
}

/**
 * Unload translations for a text domain.
 *
 * @since 3.0.0
 *
 * @param string $domain Text domain. Unique identifier for retrieving translated strings.
 * @return bool Whether textdomain was unloaded.
 */
function unload_textdomain( $domain ) {
	global $l10n;

	/**
	 * Filter the text domain for loading translation.
	 *
	 * @since 3.0.0
	 *
	 * @param bool   $override Whether to override unloading the text domain. Default false.
	 * @param string $domain   Text domain. Unique identifier for retrieving translated strings.
	 */
	$plugin_override = apply_filters( 'override_unload_textdomain', false, $domain );

	if ( $plugin_override )
		return true;

	/**
	 * Fires before the text domain is unloaded.
	 *
	 * @since 3.0.0
	 *
	 * @param string $domain Text domain. Unique identifier for retrieving translated strings.
	 */
	do_action( 'unload_textdomain', $domain );

	if ( isset( $l10n[$domain] ) ) {
		unset( $l10n[$domain] );
		return true;
	}

	return false;
}

/**
 * Load default translated strings based on locale.
 *
 * Loads the .mo file in WP_LANG_DIR constant path from WordPress root.
 * The translated (.mo) file is named based on the locale.
 *
 * @see load_textdomain()
 *
 * @since 1.5.0
 *
 * @param string $locale Optional. Locale to load. Default is the value of {@see get_locale()}.
 * @return bool Whether the textdomain was loaded.
 */
function load_default_textdomain( $locale = null ) {
	if ( null === $locale ) {
		$locale = get_locale();
	}

	// Unload previously loaded strings so we can switch translations.
	unload_textdomain( 'default' );

	$return = load_textdomain( 'default', WP_LANG_DIR . "/$locale.mo" );

	if ( ( is_multisite() || ( defined( 'WP_INSTALLING_NETWORK' ) && WP_INSTALLING_NETWORK ) ) && ! file_exists(  WP_LANG_DIR . "/admin-$locale.mo" ) ) {
		load_textdomain( 'default', WP_LANG_DIR . "/ms-$locale.mo" );
		return $return;
	}

	if ( is_admin() || defined( 'WP_INSTALLING' ) || ( defined( 'WP_REPAIRING' ) && WP_REPAIRING ) ) {
		load_textdomain( 'default', WP_LANG_DIR . "/admin-$locale.mo" );
	}

	if ( is_network_admin() || ( defined( 'WP_INSTALLING_NETWORK' ) && WP_INSTALLING_NETWORK ) )
		load_textdomain( 'default', WP_LANG_DIR . "/admin-network-$locale.mo" );

	return $return;
}

/**
 * Load a plugin's translated strings.
 *
 * If the path is not given then it will be the root of the plugin directory.
 *
 * The .mo file should be named based on the text domain with a dash, and then the locale exactly.
 *
 * @since 1.5.0
 *
 * @param string $domain          Unique identifier for retrieving translated strings
 * @param string $deprecated      Use the $plugin_rel_path parameter instead.
 * @param string $plugin_rel_path Optional. Relative path to WP_PLUGIN_DIR where the .mo file resides.
 *                                Default false.
 * @return bool True when textdomain is successfully loaded, false otherwise.
 */
function load_plugin_textdomain( $domain, $deprecated = false, $plugin_rel_path = false ) {
	$locale = get_locale();
	/**
	 * Filter a plugin's locale.
	 *
	 * @since 3.0.0
	 *
	 * @param string $locale The plugin's current locale.
	 * @param string $domain Text domain. Unique identifier for retrieving translated strings.
	 */
	$locale = apply_filters( 'plugin_locale', $locale, $domain );

	if ( false !== $plugin_rel_path	) {
		$path = WP_PLUGIN_DIR . '/' . trim( $plugin_rel_path, '/' );
	} elseif ( false !== $deprecated ) {
		_deprecated_argument( __FUNCTION__, '2.7' );
		$path = ABSPATH . trim( $deprecated, '/' );
	} else {
		$path = WP_PLUGIN_DIR;
	}

	// Load the textdomain according to the plugin first
	$mofile = $domain . '-' . $locale . '.mo';
	if ( $loaded = load_textdomain( $domain, $path . '/'. $mofile ) )
		return $loaded;

	// Otherwise, load from the languages directory
	$mofile = WP_LANG_DIR . '/plugins/' . $mofile;
	return load_textdomain( $domain, $mofile );
}

/**
 * Load the translated strings for a plugin residing in the mu-plugins directory.
 *
 * @since 3.0.0
 *
 * @param string $domain             Text domain. Unique identifier for retrieving translated strings.
 * @param string $mu_plugin_rel_path Relative to WPMU_PLUGIN_DIR directory in which the .mo file resides.
 *                                   Default empty string.
 * @return bool True when textdomain is successfully loaded, false otherwise.
 */
function load_muplugin_textdomain( $domain, $mu_plugin_rel_path = '' ) {
	/** This filter is documented in wp-includes/l10n.php */
	$locale = apply_filters( 'plugin_locale', get_locale(), $domain );
	$path = trailingslashit( WPMU_PLUGIN_DIR . '/' . ltrim( $mu_plugin_rel_path, '/' ) );

	// Load the textdomain according to the plugin first
	$mofile = $domain . '-' . $locale . '.mo';
	if ( $loaded = load_textdomain( $domain, $path . $mofile ) )
		return $loaded;

	// Otherwise, load from the languages directory
	$mofile = WP_LANG_DIR . '/plugins/' . $mofile;
	return load_textdomain( $domain, $mofile );
}

/**
 * Load the theme's translated strings.
 *
 * If the current locale exists as a .mo file in the theme's root directory, it
 * will be included in the translated strings by the $domain.
 *
 * The .mo files must be named based on the locale exactly.
 *
 * @since 1.5.0
 *
 * @param string $domain Text domain. Unique identifier for retrieving translated strings.
 * @param string $path   Optional. Path to the directory containing the .mo file.
 *                       Default false.
 * @return bool True when textdomain is successfully loaded, false otherwise.
 */
function load_theme_textdomain( $domain, $path = false ) {
	$locale = get_locale();
	/**
	 * Filter a theme's locale.
	 *
	 * @since 3.0.0
	 *
	 * @param string $locale The theme's current locale.
	 * @param string $domain Text domain. Unique identifier for retrieving translated strings.
	 */
	$locale = apply_filters( 'theme_locale', $locale, $domain );

	if ( ! $path )
		$path = get_template_directory();

	// Load the textdomain according to the theme
	$mofile = untrailingslashit( $path ) . "/{$locale}.mo";
	if ( $loaded = load_textdomain( $domain, $mofile ) )
		return $loaded;

	// Otherwise, load from the languages directory
	$mofile = WP_LANG_DIR . "/themes/{$domain}-{$locale}.mo";
	return load_textdomain( $domain, $mofile );
}

/**
 * Load the child themes translated strings.
 *
 * If the current locale exists as a .mo file in the child themes
 * root directory, it will be included in the translated strings by the $domain.
 *
 * The .mo files must be named based on the locale exactly.
 *
 * @since 2.9.0
 *
 * @param string $domain Text domain. Unique identifier for retrieving translated strings.
 * @param string $path   Optional. Path to the directory containing the .mo file.
 *                       Default false.
 * @return bool True when the theme textdomain is successfully loaded, false otherwise.
 */
function load_child_theme_textdomain( $domain, $path = false ) {
	if ( ! $path )
		$path = get_stylesheet_directory();
	return load_theme_textdomain( $domain, $path );
}

/**
 * Return the Translations instance for a text domain.
 *
 * If there isn't one, returns empty Translations instance.
 *
 * @since 2.8.0
 *
 * @param string $domain Text domain. Unique identifier for retrieving translated strings.
 * @return NOOP_Translations A Translations instance.
 */
function get_translations_for_domain( $domain ) {
	global $l10n;
	if ( !isset( $l10n[$domain] ) ) {
		$l10n[$domain] = new NOOP_Translations;
	}
	return $l10n[$domain];
}

/**
 * Whether there are translations for the text domain.
 *
 * @since 3.0.0
 *
 * @param string $domain Text domain. Unique identifier for retrieving translated strings.
 * @return bool Whether there are translations.
 */
function is_textdomain_loaded( $domain ) {
	global $l10n;
	return isset( $l10n[$domain] );
}

/**
 * Translates role name.
 *
 * Since the role names are in the database and not in the source there
 * are dummy gettext calls to get them into the POT file and this function
 * properly translates them back.
 *
 * The before_last_bar() call is needed, because older installs keep the roles
 * using the old context format: 'Role name|User role' and just skipping the
 * content after the last bar is easier than fixing them in the DB. New installs
 * won't suffer from that problem.
 *
 * @since 2.8.0
 *
 * @param string $name The role name.
 * @return string Translated role name on success, original name on failure.
 */
function translate_user_role( $name ) {
	return translate_with_gettext_context( before_last_bar($name), 'User role' );
}

/**
 * Get all available languages based on the presence of *.mo files in a given directory.
 *
 * The default directory is WP_LANG_DIR.
 *
 * @since 3.0.0
 *
 * @param string $dir A directory to search for language files.
 *                    Default WP_LANG_DIR.
 * @return array An array of language codes or an empty array if no languages are present. Language codes are formed by stripping the .mo extension from the language file names.
 */
function get_available_languages( $dir = null ) {
	$languages = array();

	foreach( (array)glob( ( is_null( $dir) ? WP_LANG_DIR : $dir ) . '/*.mo' ) as $lang_file ) {
		$lang_file = basename($lang_file, '.mo');
		if ( 0 !== strpos( $lang_file, 'continents-cities' ) && 0 !== strpos( $lang_file, 'ms-' ) &&
			0 !== strpos( $lang_file, 'admin-' ))
			$languages[] = $lang_file;
	}

	return $languages;
}

/**
 * Get installed translations.
 *
 * Looks in the wp-content/languages directory for translations of
 * plugins or themes.
 *
 * @since 3.7.0
 *
 * @param string $type What to search for. Accepts 'plugins', 'themes', 'core'.
 * @return array Array of language data.
 */
function wp_get_installed_translations( $type ) {
	if ( $type !== 'themes' && $type !== 'plugins' && $type !== 'core' )
		return array();

	$dir = 'core' === $type ? '' : "/$type";

	if ( ! is_dir( WP_LANG_DIR ) )
		return array();

	if ( $dir && ! is_dir( WP_LANG_DIR . $dir ) )
		return array();

	$files = scandir( WP_LANG_DIR . $dir );
	if ( ! $files )
		return array();

	$language_data = array();

	foreach ( $files as $file ) {
		if ( '.' === $file[0] || is_dir( $file ) ) {
			continue;
		}
		if ( substr( $file, -3 ) !== '.po' ) {
			continue;
		}
		if ( ! preg_match( '/(?:(.+)-)?([A-Za-z_]{2,6}).po/', $file, $match ) ) {
			continue;
		}
		if ( ! in_array( substr( $file, 0, -3 ) . '.mo', $files ) )  {
			continue;
		}

		list( , $textdomain, $language ) = $match;
		if ( '' === $textdomain ) {
			$textdomain = 'default';
		}
		$language_data[ $textdomain ][ $language ] = wp_get_pomo_file_data( WP_LANG_DIR . "$dir/$file" );
	}
	return $language_data;
}

/**
 * Extract headers from a PO file.
 *
 * @since 3.7.0
 *
 * @param string $po_file Path to PO file.
 * @return array PO file headers.
 */
function wp_get_pomo_file_data( $po_file ) {
	$headers = get_file_data( $po_file, array(
		'POT-Creation-Date'  => '"POT-Creation-Date',
		'PO-Revision-Date'   => '"PO-Revision-Date',
		'Project-Id-Version' => '"Project-Id-Version',
		'X-Generator'        => '"X-Generator',
	) );
	foreach ( $headers as $header => $value ) {
		// Remove possible contextual '\n' and closing double quote.
		$headers[ $header ] = preg_replace( '~(\\\n)?"$~', '', $value );
	}
	return $headers;
}

/**
 * Language selector.
 *
 * @since 4.0.0
 *
 * @see get_available_languages()
 * @see wp_get_available_translations()
 *
 * @param string|array $args {
 *     Optional. Array or string of arguments for outputting the language selector.
 *
 *     @type string  $id                           ID attribute of the select element. Default empty.
 *     @type string  $name                         Name attribute of the select element. Default empty.
 *     @type array   $languages                    List of installed languages, contain only the locales.
 *                                                 Default empty array.
 *     @type array   $translations                 List of available translations. Default result of
 *                                                 {@see wp_get_available_translations()}.
 *     @type string  $selected                     Language which should be selected. Default empty.
 *     @type bool    $show_available_translations  Whether to show available translations. Default true.
 * }
 */
function wp_dropdown_languages( $args = array() ) {

	$args = wp_parse_args( $args, array(
		'id'           => '',
		'name'         => '',
		'languages'    => array(),
		'translations' => array(),
		'selected'     => '',
		'show_available_translations' => true,
	) );

	$translations = $args['translations'];
	if ( empty( $translations ) ) {
		require_once( ABSPATH . 'wp-admin/includes/translation-install.php' );
		$translations = wp_get_available_translations();
	}

	/*
	 * $args['languages'] should only contain the locales. Find the locale in
	 * $translations to get the native name. Fall back to locale.
	 */
	$languages = array();
	foreach ( $args['languages'] as $locale ) {
		if ( isset( $translations[ $locale ] ) ) {
			$translation = $translations[ $locale ];
			$languages[] = array(
				'language'    => $translation['language'],
				'native_name' => $translation['native_name'],
				'lang'        => current( $translation['iso'] ),
			);

			// Remove installed language from available translations.
			unset( $translations[ $locale ] );
		} else {
			$languages[] = array(
				'language'    => $locale,
				'native_name' => $locale,
				'lang'        => '',
			);
		}
	}

	$translations_available = ( ! empty( $translations ) && $args['show_available_translations'] );

	printf( '<select name="%s" id="%s">', esc_attr( $args['name'] ), esc_attr( $args['id'] ) );

	// Holds the HTML markup.
	$structure = array();

	// List installed languages.
	if ( $translations_available ) {
		$structure[] = '<optgroup label="' . esc_attr_x( 'Installed', 'translations' ) . '">';
	}
	$structure[] = '<option value="" lang="en" data-installed="1">English (United States)</option>';
	foreach ( $languages as $language ) {
		$structure[] = sprintf(
			'<option value="%s" lang="%s"%s data-installed="1">%s</option>',
			esc_attr( $language['language'] ),
			esc_attr( $language['lang'] ),
			selected( $language['language'], $args['selected'], false ),
			esc_html( $language['native_name'] )
		);
	}
	if ( $translations_available ) {
		$structure[] = '</optgroup>';
	}

	// List available translations.
	if ( $translations_available ) {
		$structure[] = '<optgroup label="' . esc_attr_x( 'Available', 'translations' ) . '">';
		foreach ( $translations as $translation ) {
			$structure[] = sprintf(
				'<option value="%s" lang="%s"%s>%s</option>',
				esc_attr( $translation['language'] ),
				esc_attr( current( $translation['iso'] ) ),
				selected( $translation['language'], $args['selected'], false ),
				esc_html( $translation['native_name'] )
			);
		}
		$structure[] = '</optgroup>';
	}

	echo join( "\n", $structure );

	echo '</select>';
}

Bây giờ, nếu bạn muốn dịch cho WordPress thì bạn chỉ cần thêm hàm bên dưới vào tập tin functions.php của giao diện.

function sb_theme_translate_wp_front_end($translation, $text) {
    if(!is_admin() || (is_admin() && defined('DOING_AJAX'))) {
        switch($text) {
            case 'Email':
                $translation = 'Địa chỉ email';
                break;
            case 'Password':
                $translation = 'Mật khẩu';
                break;
        }
    }
    return $translation;
}
add_filter('gettext', 'sb_theme_translate_wp_front_end', 10, 2);

Bạn cứ dùng filter gettext trước, nếu sau khi đã dịch mà ngôn ngữ vẫn là Tiếng Anh thì bạn tiếp tục chuyển sang dùng các filter khác. Nếu bạn muốn biết chính xác phải nên dùng filter nào thì bạn mở chỗ text đó lên xem người ta dùng hàm gì, và đặt biệt nếu từ ngữ không được đặt trong các hàm __, _e, _n,… (các hàm ngôn ngữ) thì hệ thống sẽ không dịch được.

Gửi bình luận của bạn

Gửi bình luận

Địa chỉ email của bạn sẽ được giữ bí mật. Những mục bắt buộc được đánh dấu *