' prefixed lines * - core/code → fenced ``` block * - core/image → '' * - core/separator → '---' * - core/group / columns / column / * core/buttons → render children only * - everything else → stripped plaintext fallback * * Inline mapping (applied to each block's innerHTML before stripping): * - / → **bold** * - / → _italic_ * - → [text](href) * - inline → `code` * * Blocks are separated by a blank line. * * @since 1.2.0 */ class BlockMarkdown { /** * Render raw block markup to Markdown. * * @param string $post_content Raw block markup. * @return string Markdown rendering (no trailing newline). * * @since 1.2.0 */ public function render( string $post_content ): string { if ( trim( $post_content ) === '' ) { return ''; } $blocks = parse_blocks( $post_content ); return $this->render_blocks( $blocks ); } /** * Render a list of parsed blocks, joining each rendered block with a blank line. * * @param array> $blocks Parsed blocks. * @return string Markdown. * * @since 1.2.0 */ private function render_blocks( array $blocks ): string { $parts = []; foreach ( $blocks as $block ) { $name = $block['blockName'] ?? null; // Skip the empty whitespace "freeform" separators parse_blocks emits. if ( $name === null && trim( (string) ( $block['innerHTML'] ?? '' ) ) === '' ) { continue; } $rendered = $this->render_block( $block ); if ( trim( $rendered ) !== '' ) { $parts[] = $rendered; } } return implode( "\n\n", $parts ); } /** * Render a single parsed block to Markdown. * * @param array $block Parsed block. * @return string Markdown. * * @since 1.2.0 */ private function render_block( array $block ): string { $name = $block['blockName'] ?? null; $attrs = isset( $block['attrs'] ) && is_array( $block['attrs'] ) ? $block['attrs'] : []; $inner_html = (string) ( $block['innerHTML'] ?? '' ); $inner_blocks = isset( $block['innerBlocks'] ) && is_array( $block['innerBlocks'] ) ? $block['innerBlocks'] : []; switch ( $name ) { case 'core/heading': $level = isset( $attrs['level'] ) ? (int) $attrs['level'] : 2; if ( $level < 1 || $level > 6 ) { $level = 2; } return str_repeat( '#', $level ) . ' ' . $this->inline( $inner_html ); case 'core/list': return $this->render_list( $block ); case 'core/list-item': // A list-item rendered on its own (defensive) — emit one bullet. return '- ' . $this->inline( $inner_html ); case 'core/quote': case 'core/pullquote': return $this->render_quote( $block, $attrs, $inner_html, $inner_blocks ); case 'core/code': case 'core/preformatted': return $this->render_code( $inner_html ); case 'core/image': return $this->render_image( $attrs, $inner_html ); case 'core/separator': return '---'; case 'core/group': case 'core/columns': case 'core/column': case 'core/buttons': // Structural wrappers — render their children only. return $this->render_blocks( $inner_blocks ); case 'core/paragraph': return $this->inline( $inner_html ); default: // Unknown / unmapped block: render children if any, else fall // back to the block's own stripped plaintext. if ( $inner_blocks !== [] ) { $children = $this->render_blocks( $inner_blocks ); if ( trim( $children ) !== '' ) { return $children; } } return $this->plaintext( $inner_html ); } } /** * Render a core/list block (and its list-item children) to Markdown. * * Ordered lists use '1.' markers; unordered lists use '-'. Nested lists are * indented by two spaces per level. * * @param array $block The list block. * @param int $depth Current nesting depth (0 = top level). * @return string Markdown list. * * @since 1.2.0 */ private function render_list( array $block, int $depth = 0 ): string { $attrs = isset( $block['attrs'] ) && is_array( $block['attrs'] ) ? $block['attrs'] : []; $ordered = ! empty( $attrs['ordered'] ); $items = isset( $block['innerBlocks'] ) && is_array( $block['innerBlocks'] ) ? $block['innerBlocks'] : []; $lines = []; $number = 1; $indent = str_repeat( ' ', $depth ); foreach ( $items as $item ) { if ( ( $item['blockName'] ?? null ) !== 'core/list-item' ) { continue; } $marker = $ordered ? ( $number . '. ' ) : '- '; $text = $this->inline( (string) ( $item['innerHTML'] ?? '' ) ); $lines[] = $indent . $marker . $text; ++$number; // A list-item may contain a nested core/list. $nested = isset( $item['innerBlocks'] ) && is_array( $item['innerBlocks'] ) ? $item['innerBlocks'] : []; foreach ( $nested as $child ) { if ( ( $child['blockName'] ?? null ) === 'core/list' ) { $lines[] = $this->render_list( $child, $depth + 1 ); } } } return implode( "\n", $lines ); } /** * Render a quote/pullquote block to a Markdown blockquote. * * @param array $block The quote block. * @param array $attrs Block attributes. * @param string $inner_html The block's inner HTML. * @param array> $inner_blocks Inner blocks (paragraphs). * @return string Markdown blockquote. * * @since 1.2.0 */ private function render_quote( array $block, array $attrs, string $inner_html, array $inner_blocks ): string { // Quotes wrap inner paragraph blocks; pullquotes store text inline. if ( $inner_blocks !== [] ) { $body = $this->render_blocks( $inner_blocks ); } else { $body = $this->inline( $inner_html ); } $lines = []; foreach ( explode( "\n", $body ) as $line ) { $lines[] = trim( $line ) === '' ? '>' : '> ' . $line; } $citation = isset( $attrs['citation'] ) ? trim( (string) $attrs['citation'] ) : ''; if ( $citation === '' ) { // Pullquote/quote can also carry the citation in a tag. $citation = $this->cite_from_html( $inner_html ); } if ( $citation !== '' ) { $lines[] = '>'; $lines[] = '> — ' . $citation; } return implode( "\n", $lines ); } /** * Render a code/preformatted block as a fenced Markdown code block. * * @param string $inner_html The block's inner HTML. * @return string Fenced code block. * * @since 1.2.0 */ private function render_code( string $inner_html ): string { $code = $this->plaintext( $inner_html ); return "```\n" . $code . "\n```"; } /** * Render an image block as Markdown image syntax. * * The url/alt come from attributes when present, otherwise they are read * from the inner tag. * * @param array $attrs Block attributes. * @param string $inner_html The block's inner HTML. * @return string Markdown image (with optional caption line). * * @since 1.2.0 */ private function render_image( array $attrs, string $inner_html ): string { $url = isset( $attrs['url'] ) ? (string) $attrs['url'] : ''; $alt = isset( $attrs['alt'] ) ? (string) $attrs['alt'] : ''; if ( $url === '' && preg_match( '/]*\bsrc="([^"]*)"/i', $inner_html, $m ) ) { $url = $m[1]; } if ( $alt === '' && preg_match( '/]*\balt="([^"]*)"/i', $inner_html, $m ) ) { $alt = $m[1]; } $markdown = ''; $caption = isset( $attrs['caption'] ) ? trim( (string) $attrs['caption'] ) : ''; if ( $caption === '' && preg_match( '/]*>(.*?)<\/figcaption>/is', $inner_html, $m ) ) { $caption = $this->plaintext( $m[1] ); } if ( $caption !== '' ) { $markdown .= "\n\n" . $this->inline( $caption ); } return $markdown; } /** * Extract a citation from a trailing tag in the HTML. * * @param string $html Inner HTML. * @return string Citation text, or an empty string. * * @since 1.2.0 */ private function cite_from_html( string $html ): string { if ( preg_match( '/]*>(.*?)<\/cite>/is', $html, $m ) ) { return $this->plaintext( $m[1] ); } return ''; } /** * Convert a small set of inline HTML tags in a fragment to Markdown, then * strip any remaining tags and decode entities. * * Block-level boundaries (

,
, , ) collapse to a single * space so multi-paragraph innerHTML does not run words together. * * @param string $html Block inner HTML. * @return string Inline Markdown text. * * @since 1.2.0 */ private function inline( string $html ): string { $text = $html; // Links: capture href and inner text. Run before generic tag stripping. $text = preg_replace_callback( '/]*\bhref="([^"]*)"[^>]*>(.*?)<\/a>/is', static function ( array $m ): string { $label = trim( wp_strip_all_tags( $m[2] ) ); $href = $m[1]; if ( $label === '' ) { return $href; } return '[' . $label . '](' . $href . ')'; }, $text ) ?? $text; // Inline code. $text = preg_replace( '/]*>(.*?)<\/code>/is', '`$1`', $text ) ?? $text; // Bold. $text = preg_replace( '/<(strong|b)\b[^>]*>(.*?)<\/\1>/is', '**$2**', $text ) ?? $text; // Italic. $text = preg_replace( '/<(em|i)\b[^>]*>(.*?)<\/\1>/is', '_$2_', $text ) ?? $text; // Collapse block boundaries to spaces so words don't fuse together. $text = preg_replace( '/<\/(p|li|h[1-6]|blockquote|figcaption)>/i', ' ', $text ) ?? $text; $text = preg_replace( '//i', ' ', $text ) ?? $text; // Strip any remaining tags. $text = wp_strip_all_tags( $text ); // Decode entities the inner HTML carried (e.g. &, <). $text = html_entity_decode( $text, ENT_QUOTES | ENT_HTML5, 'UTF-8' ); // Collapse runs of whitespace introduced by boundary replacement. $text = preg_replace( '/[ \t]+/', ' ', $text ) ?? $text; return trim( $text ); } /** * Strip all tags and decode entities to bare text (the unknown-block fallback). * * @param string $html Inner HTML. * @return string Plain text. * * @since 1.2.0 */ private function plaintext( string $html ): string { $text = wp_strip_all_tags( $html ); $text = html_entity_decode( $text, ENT_QUOTES | ENT_HTML5, 'UTF-8' ); return trim( $text ); } }