WP HTML Table Processor

class-wp-html-table-processor.php

<?php
/**
 * WP_HTML_Table_Processor
 * @author Seth Rubenstein
 */

/**
 * Pass in a table and get back an array of the header, rows, and footer cells quickly and effeciently.
 * 
 * The WP_HTML_Tag_Processor bookmark tree navigation is heavily cribbed from WP_Directive_Processor class https://github.com/WordPress/block-interactivity-experiments/pull/169/files#diff-ad36045951e27010af027ae380350ae4b07b56a659a3127b40b7967b2308d5bc
 * @package 
 */
class WP_HTML_Table_Processor extends WP_HTML_Tag_Processor {
	/**
	 * 
	 * Find the matching closing tag for an opening tag.
	 *
	 * When called while on an open tag, traverse the HTML until we find
	 * the matching closing tag, respecting any in-between content, including
	 * nested tags of the same name. Return false when called on a closing or
	 * void tag, or if no matching closing tag was found.
	 *
	 * @return bool True if a matching closing tag was found.
	 */
	public function next_balanced_closer() {
		$depth = 0;

		$tag_name = $this->get_tag();

		while ( $this->next_tag(
			array(
				'tag_name'    => $tag_name,
				'tag_closers' => 'visit',
			)
		) ) {
			if ( ! $this->is_tag_closer() ) {
				$depth++;
				continue;
			}

			if ( 0 === $depth ) {
				return true;
			}

			$depth--;
		}

		return false;
	}

	public function get_matching_tag_bookmarks() {
		$i = 0;
		while ( array_key_exists( 'start-' . $i, $this->bookmarks ) ) {
			++$i;
		}
		$start_name = 'start-' . $i;

		$this->set_bookmark( $start_name );
		if ( ! $this->next_balanced_closer() ) {
			$this->release_bookmark( $start_name );
			return false;
		}

		$i = 0;
		while ( array_key_exists( 'end-' . $i, $this->bookmarks ) ) {
			++$i;
		}
		$end_name = 'end-' . $i;
		$this->set_bookmark( $end_name );

		return array( $start_name, $end_name );
	}

	/**
	 * Return the content between two matching tags.
	 *
	 * When called on an opening tag, return the HTML content found between
	 * that opening tag and its matching closing tag.
	 *
	 * @return string The content between the current opening and its matching closing tag.
	 */
	public function get_inner_html() {
		$bookmarks = $this->get_matching_tag_bookmarks();

		if ( ! $bookmarks ) {
			return false;
		}
		list( $start_name, $end_name ) = $bookmarks;

		$start = $this->bookmarks[ $start_name ]->end + 1;
		$end   = $this->bookmarks[ $end_name ]->start;

		$this->seek( $start_name ); // Return to original position.
		$this->release_bookmark( $start_name );
		$this->release_bookmark( $end_name );

		return substr( $this->html, $start, $end - $start );
	}

	/**
	 * Returns the data from the table as an array.
	 * 
	 * @return array 
	 */
	public function get_data() {
		$table_headers = array();
		$table_rows = array();
		$table_footer = array();

		$this->next_tag( 'table' );

		$this->next_tag( 'thead' );
		$this->set_bookmark( 'thead' );
		$this->next_tag( 'tr' );
		while ( $this->next_tag( 'th' ) ) {
			$table_headers[] = $this->get_inner_html();
		}
		// Cleaning the tree as we go
		$this->seek( 'thead' );

		$this->next_tag( 'tbody' );
		$this->set_bookmark( 'tbody' );
		while ( $this->next_tag( 'tr' ) ) {
			while ( $this->next_tag( 'td' ) ) {
				$table_rows[] = $this->get_inner_html();
			}
		}
		// Cleaning the tree as we go
		$this->seek( 'tbody' );
		// Split table rows into cells by the number of headers, quicker and easier than trying to compute and iterate over columns/cells in WP_HTML_Tag_Processor.
		$table_rows = array_chunk( $table_rows, count( $table_headers ) );

		$this->next_tag( 'tfoot' );
		$this->set_bookmark( 'tfoot' );
		while ( $this->next_tag( 'tr' ) ) {
			$table_footer[] = $this->get_inner_html();
		}
		// Cleaning the tree as we go
		$this->seek( 'tfoot' );
		// Split table rows into cells by the number of headers
		$table_footer = array_chunk( $table_footer, count( $table_headers ) );

		return array(
			'header' => $table_headers,
			'rows'   => $table_rows,
			'footer' => $table_footer,
		);
	}
}

/**
 * Processes a table block into an array of data. All HTML is stripped from the table.
 * 
 * Tested with the core/table block and flexible-table/table block.
 * 
 * @param mixed $table_content 
 * @return array
 */
function parse_table_block_into_array( $table_content ) {
	// strip $table_content of any <!-- comments -->, which can interfer with the parser below
	$table_content = preg_replace( '/<!--(.|\s)*?-->/', '', $table_content );
	$processor = new WP_HTML_Table_Processor( $table_content );
	return $processor->get_data();
}

Just an update for those following along at home. This ^ is super rough first look, an exploration of the WP_HTML_Tag_Processor class so I can understand how it works. I'll be making this more performant and not reliant on multiple calls to the class to process correctly.

Updated to parse through the the table data more effeciently, now WP_HTML_Table_Processor will process an entire table.

Usage:

<?php
$table = new WP_HTML_Table_Processor('<table><thead>...</thead><tbody>...</tbody><tfoot>...</tfoot></table>');
$data = $table->get_data();

Working on some additional bookmarks management and cleaning next week, expect an update next week, also man I'd really like to figure out how to gather cells as pairs for each row using bookmarks but thats going to take alot of trial and error and it might not be as quick as my current solution.