I18N: Add JavaScript translation support.

Adds the `wp_set_script_translations()` function which registers translations for a JavaScript file. This function takes a handle, domain and optionally a path and ensures JavaScript translation files are loaded if they exist.

Merges [43825,43828,43859,43898] from the 5.0 branch to trunk.

Props herregroen, atimmer, omarreiss, nerrad, swissspidy, ocean90, georgestephanis.
Fixes #45103, #45256.


Built from https://develop.svn.wordpress.org/trunk@44169


git-svn-id: http://core.svn.wordpress.org/trunk@43999 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-wp-dependency.php

@@ -67,6 +67,22 @@ class _WP_Dependency {
 	 */
 	public $extra = array();
 
+	/**
+	 * Translation textdomain set for this dependency.
+	 *
+	 * @since 5.0.0
+	 * @var string
+	 */
+	public $textdomain;
+
+	/**
+	 * Translation path set for this dependency.
+	 *
+	 * @since 5.0.0
+	 * @var string
+	 */
+	public $translations_path;
+
 	/**
 	 * Setup dependencies.
 	 *
@@ -96,4 +112,12 @@ class _WP_Dependency {
 		return true;
 	}
 
+	public function set_translations( $domain, $path = null ) {
+		if ( ! is_string( $domain ) ) {
+			return false;
+		}
+		$this->textdomain        = $domain;
+		$this->translations_path = $path;
+		return true;
+	}
 }

wp-includes/class.wp-scripts.php

@@ -330,6 +330,11 @@ class WP_Scripts extends WP_Dependencies {
 			return true;
 		}
 
+		$translations = $this->print_translations( $handle, false );
+		if ( $translations ) {
+			$translations = sprintf( "<script type='text/javascript'>\n%s\n</script>\n", $translations );
+		}
+
 		if ( ! preg_match( '|^(https?:)?//|', $src ) && ! ( $this->content_url && 0 === strpos( $src, $this->content_url ) ) ) {
 			$src = $this->base_url . $src;
 		}
@@ -345,7 +350,7 @@ class WP_Scripts extends WP_Dependencies {
 			return true;
 		}
 
-		$tag = "{$cond_before}{$before_handle}<script type='text/javascript' src='$src'></script>\n{$after_handle}{$cond_after}";
+		$tag = "{$translations}{$cond_before}{$before_handle}<script type='text/javascript' src='$src'></script>\n{$after_handle}{$cond_after}";
 
 		/**
 		 * Filters the HTML script tag of an enqueued script.
@@ -490,6 +495,67 @@ class WP_Scripts extends WP_Dependencies {
 		return parent::set_group( $handle, $recursion, $grp );
 	}
 
+	/**
+	 * Sets a translation textdomain.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param string $handle Name of the script to register a translation domain to.
+	 * @param string $domain The textdomain.
+	 * @param string $path   Optional. The full file path to the directory containing translation files.
+	 *
+	 * @return bool True if the textdomain was registered, false if not.
+	 */
+	public function set_translations( $handle, $domain, $path = null ) {
+		if ( ! isset( $this->registered[ $handle ] ) ) {
+			return false;
+		}
+
+		/** @var \_WP_Dependency $obj */
+		$obj = $this->registered[ $handle ];
+
+		if ( ! in_array( 'wp-i18n', $obj->deps, true ) ) {
+			$obj->deps[] = 'wp-i18n';
+		}
+		return $obj->set_translations( $domain, $path );
+	}
+
+	/**
+	 * Prints translations set for a specific handle.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param string $handle Name of the script to add the inline script to. Must be lowercase.
+	 * @param bool   $echo   Optional. Whether to echo the script instead of just returning it.
+	 *                       Default true.
+	 * @return string|false Script on success, false otherwise.
+	 */
+	public function print_translations( $handle, $echo = true ) {
+		if ( ! isset( $this->registered[ $handle ] ) || empty( $this->registered[ $handle ]->textdomain ) ) {
+			return false;
+		}
+
+		$domain = $this->registered[ $handle ]->textdomain;
+		$path   = $this->registered[ $handle ]->translations_path;
+
+		$json_translations = load_script_textdomain( $handle, $domain, $path );
+
+		if ( ! $json_translations ) {
+			// Register empty locale data object to ensure the domain still exists.
+			$json_translations = '{ "locale_data": { "messages": { "": {} } } }';
+		}
+
+		$output = '(function( translations ){' .
+					  'wp.i18n.setLocaleData( translations.locale_data, "' . $domain . '" );' .
+				  '})(' . $json_translations . ');';
+
+		if ( $echo ) {
+			printf( "<script type='text/javascript'>\n%s\n</script>\n", $output );
+		}
+
+		return $output;
+	}
+
 	/**
 	 * Determines script dependencies.
 	 *

wp-includes/functions.wp-scripts.php

@@ -200,6 +200,32 @@ function wp_localize_script( $handle, $object_name, $l10n ) {
 	return $wp_scripts->localize( $handle, $object_name, $l10n );
 }
 
+/**
+ * Sets translated strings for a script.
+ *
+ * Works only if the script has already been added.
+ *
+ * @see WP_Scripts::set_translations()
+ * @global WP_Scripts $wp_scripts The WP_Scripts object for printing scripts.
+ *
+ * @since 5.0.0
+ *
+ * @param string $handle Script handle the textdomain will be attached to.
+ * @param string $domain The textdomain.
+ * @param string $path   Optional. The full file path to the directory containing translation files.
+ *
+ * @return bool True if the textdomain was successfully localized, false otherwise.
+ */
+function wp_set_script_translations( $handle, $domain, $path = null ) {
+	global $wp_scripts;
+	if ( ! ( $wp_scripts instanceof WP_Scripts ) ) {
+		_wp_scripts_maybe_doing_it_wrong( __FUNCTION__ );
+		return false;
+	}
+
+	return $wp_scripts->set_translations( $handle, $domain, $path );
+}
+
 /**
  * Remove a registered script.
  *

wp-includes/l10n.php

@@ -893,6 +893,91 @@ function load_child_theme_textdomain( $domain, $path = false ) {
 	return load_theme_textdomain( $domain, $path );
 }
 
+/**
+ * Load the script translated strings.
+ *
+ * @see WP_Scripts::set_translations()
+ * @link https://core.trac.wordpress.org/ticket/45103
+ * @global WP_Scripts $wp_scripts The WP_Scripts object for printing scripts.
+ *
+ * @since 5.0.0
+ *
+ * @param string $handle Name of the script to register a translation domain to.
+ * @param string $domain The textdomain.
+ * @param string $path   Optional. The full file path to the directory containing translation files.
+ *
+ * @return false|string False if the script textdomain could not be loaded, the translated strings
+ *                      in JSON encoding otherwise.
+ */
+function load_script_textdomain( $handle, $domain, $path = null ) {
+	global $wp_scripts;
+
+	$path   = untrailingslashit( $path );
+	$locale = is_admin() ? get_locale() : get_user_locale();
+
+	// If a path was given and the handle file exists simply return it.
+	$file_base       = $domain === 'default' ? $locale : $domain . '-' . $locale;
+	$handle_filename = $file_base . '-' . $handle . '.json';
+	if ( $path && file_exists( $path . '/' . $handle_filename ) ) {
+		return file_get_contents( $path . '/' . $handle_filename );
+	}
+
+	$obj = $wp_scripts->registered[ $handle ];
+
+	/** This filter is documented in wp-includes/class.wp-scripts.php */
+	$src = esc_url( apply_filters( 'script_loader_src', $obj->src, $handle ) );
+
+	$relative       = false;
+	$languages_path = WP_LANG_DIR;
+
+	$src_url     = wp_parse_url( $src );
+	$content_url = wp_parse_url( content_url() );
+	$site_url    = wp_parse_url( site_url() );
+
+	// If the host is the same or it's a relative URL.
+	if (
+		strpos( $src_url['path'], $content_url['path'] ) === 0 &&
+		( ! isset( $src_url['host'] ) || $src_url['host'] !== $content_url['host'] )
+	) {
+		// Make the src relative the specific plugin or theme.
+		$relative = trim( substr( $src, strlen( $content_url['path'] ) ), '/' );
+		$relative = explode( '/', $relative );
+
+		$languages_path = WP_LANG_DIR . '/' . $relative[0];
+
+		$relative = array_slice( $relative, 2 );
+		$relative = implode( '/', $relative );
+	} elseif ( ! isset( $src_url['host'] ) || $src_url['host'] !== $site_url['host'] ) {
+		if ( ! isset( $site_url['path'] ) ) {
+			$relative = trim( $src_url['path'], '/' );
+		} elseif ( ( strpos( $src_url['path'], $site_url['path'] ) === 0 ) ) {
+			// Make the src relative to the WP root.
+			$relative = substr( $src, strlen( $site_url['path'] ) );
+			$relative = trim( $relative, '/' );
+		}
+	}
+
+	// If the source is not from WP.
+	if ( false === $relative ) {
+		return false;
+	}
+
+	// Translations are always based on the unminified filename.
+	if ( substr( $relative, -7 ) === '.min.js' ) {
+		$relative = substr( $relative, 0, -7 ) . '.js';
+	}
+
+	$md5_filename = $file_base . '-' . md5( $relative ) . '.json';
+	if ( $path && file_exists( $path . '/' . $md5_filename ) ) {
+		return file_get_contents( $path . '/' . $md5_filename );
+	}
+	if ( file_exists( $languages_path . '/' . $md5_filename ) ) {
+		return file_get_contents( $languages_path . '/' . $md5_filename );
+	}
+
+	return false;
+}
+
 /**
  * Loads plugin and theme textdomains just-in-time.
  *

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44168';
+$wp_version = '5.1-alpha-44169';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.