create-block-theme/includes/create-theme/theme-locale.php

<?php
/*
* Locale related functionality
*/
class CBT_Theme_Locale {

	/**
	 * Escape a string for localization.
	 *
	 * @param string $string The string to escape.
	 * @return string The escaped string.
	 */
	public static function escape_string( $string ) {
		// Avoid escaping if the text is not a string.
		if ( ! is_string( $string ) ) {
			return $string;
		}

		// Check if the text is already escaped.
		if ( str_starts_with( $string, '<?php echo' ) ) {
			return $string;
		}

		$string = addcslashes( $string, "'" );
		return "<?php echo __('" . $string . "', '" . wp_get_theme()->get( 'TextDomain' ) . "');?>";
	}

	/**
	 * Get a replacement pattern for escaping the text from the html content of a block.
	 *
	 * @param string $block_name The block name.
	 * @return array|null The regex patterns to match the content that needs to be escaped.
	 *      Returns null if the block is not supported.
	 *      Returns an array of regex patterns if the block has html elements that need to be escaped.
	 */
	private static function get_text_replacement_patterns_for_html( $block_name ) {
		switch ( $block_name ) {
			case 'core/paragraph':
				return array( '/(<p[^>]*>)(.*?)(<\/p>)/' );
			case 'core/heading':
				return array( '/(<h[^>]*>)(.*?)(<\/h[^>]*>)/' );
			case 'core/list-item':
				return array( '/(<li[^>]*>)(.*?)(<\/li>)/' );
			case 'core/verse':
				return array( '/(<pre[^>]*>)(.*?)(<\/pre>)/' );
			case 'core/button':
				return array( '/(<a[^>]*>)(.*?)(<\/a>)/' );
			case 'core/image':
			case 'core/cover':
			case 'core/media-text':
				return array( '/alt="(.*?)"/' );
			case 'core/quote':
			case 'core/pullquote':
				return array(
					'/(<p[^>]*>)(.*?)(<\/p>)/',
					'/(<cite[^>]*>)(.*?)(<\/cite>)/',
				);
			case 'core/table':
				return array(
					'/(<td[^>]*>)(.*?)(<\/td>)/',
					'/(<th[^>]*>)(.*?)(<\/th>)/',
					'/(<figcaption[^>]*>)(.*?)(<\/figcaption>)/',
				);
			default:
				return null;
		}
	}

	/*
	 * Localize text in text blocks.
	 *
	 * @param array $blocks The blocks to localize.
	 * @return array The localized blocks.
	 */
	public static function escape_text_content_of_blocks( $blocks ) {
		foreach ( $blocks as &$block ) {

			// Recursively escape the inner blocks.
			if ( ! empty( $block['innerBlocks'] ) ) {
				$block['innerBlocks'] = self::escape_text_content_of_blocks( $block['innerBlocks'] );
			}

			/*
			 * Set the pattern based on the block type.
			 * The pattern is used to match the content that needs to be escaped.
			 * Patterns are defined in the get_text_replacement_patterns_for_html method.
			 */
			$patterns = self::get_text_replacement_patterns_for_html( $block['blockName'] );

			// If the block does not have any patterns leave the block as is and continue to the next block.
			if ( ! $patterns ) {
				continue;
			}

			// Builds the replacement callback function based on the block type.
			switch ( $block['blockName'] ) {
				case 'core/paragraph':
				case 'core/heading':
				case 'core/list-item':
				case 'core/verse':
				case 'core/button':
				case 'core/quote':
				case 'core/pullquote':
				case 'core/table':
					$replace_content_callback = function ( $content, $pattern ) {
						if ( empty( $content ) ) {
							return;
						}
						return preg_replace_callback(
							$pattern,
							function( $matches ) {
								return $matches[1] . self::escape_string( $matches[2] ) . $matches[3];
							},
							$content
						);
					};
					break;
				case 'core/image':
				case 'core/cover':
				case 'core/media-text':
					$replace_content_callback = function ( $content, $pattern ) {
						if ( empty( $content ) ) {
							return;
						}
						return preg_replace_callback(
							$pattern,
							function( $matches ) {
								return 'alt="' . self::escape_string( $matches[1] ) . '"';
							},
							$content
						);
					};
					break;
				default:
					$replace_content_callback = null;
					break;
			}

			// Apply the replacement patterns to the block content.
			foreach ( $patterns as $pattern ) {
				if (
					! empty( $block['innerContent'] ) &&
					is_callable( $replace_content_callback )
				) {
					$block['innerContent'] = is_array( $block['innerContent'] )
					? array_map(
						function( $content ) use ( $replace_content_callback, $pattern ) {
							return $replace_content_callback( $content, $pattern );
						},
						$block['innerContent']
					)
					: $replace_content_callback( $block['innerContent'], $pattern );
				}
			}
		}
		return $blocks;
	}
}