<?php
namespace League\HTMLToMarkdown;
/**
* Class HtmlConverter
*
* A helper class to convert HTML to Markdown.
*
* @author Colin O'Dell <colinodell@gmail.com>
* @author Nick Cernis <nick@cern.is>
*
* @link https://github.com/thephpleague/html-to-markdown/ Latest version on GitHub.
*
* @license http://www.opensource.org/licenses/mit-license.php MIT
*/
class HtmlConverter
{
/**
* @var Environment
*/
protected $environment;
/**
* Constructor
*
* @param Environment|array $options Environment object or configuration options
*/
public function __construct($options = array())
{
if ($options instanceof Environment) {
$this->environment = $options;
} elseif (is_array($options)) {
$defaults = array(
'header_style' => 'setext', // Set to 'atx' to output H1 and H2 headers as # Header1 and ## Header2
'suppress_errors' => true, // Set to false to show warnings when loading malformed HTML
'strip_tags' => false, // Set to true to strip tags that don't have markdown equivalents. N.B. Strips tags, not their content. Useful to clean MS Word HTML output.
'bold_style' => '**', // Set to '__' if you prefer the underlined style
'italic_style' => '_', // Set to '*' if you prefer the asterisk style
'remove_nodes' => '', // space-separated list of dom nodes that should be removed. example: 'meta style script'
'hard_break' => false, // Set to true to turn <br> into `\n` instead of ` \n`
'list_item_style' => '-', // Set the default character for each <li> in a <ul>. Can be '-', '*', or '+'
);
$this->environment = Environment::createDefaultEnvironment($defaults);
$this->environment->getConfig()->merge($options);
}
}
/**
* @return Environment
*/
public function getEnvironment()
{
return $this->environment;
}
/**
* @return Configuration
*/
public function getConfig()
{
return $this->environment->getConfig();
}
/**
* Convert
*
* @see HtmlConverter::convert
*
* @param string $html
*
* @return string The Markdown version of the html
*/
public function __invoke($html)
{
return $this->convert($html);
}
/**
* Convert
*
* Loads HTML and passes to getMarkdown()
*
* @param string $html
*
* @throws \InvalidArgumentException
*
* @return string The Markdown version of the html
*/
public function convert($html)
{
if (trim($html) === '') {
return '';
}
$document = $this->createDOMDocument($html);
// Work on the entire DOM tree (including head and body)
if (!($root = $document->getElementsByTagName('html')->item(0))) {
throw new \InvalidArgumentException('Invalid HTML was provided');
}
$rootElement = new Element($root);
$this->convertChildren($rootElement);
// Store the now-modified DOMDocument as a string
$markdown = $document->saveHTML();
return $this->sanitize($markdown);
}
/**
* @param string $html
*
* @return \DOMDocument
*/
private function createDOMDocument($html)
{
$document = new \DOMDocument();
if ($this->getConfig()->getOption('suppress_errors')) {
// Suppress conversion errors (from http://bit.ly/pCCRSX)
libxml_use_internal_errors(true);
}
// Hack to load utf-8 HTML (from http://bit.ly/pVDyCt)
$document->loadHTML('<?xml encoding="UTF-8">' . $html);
$document->encoding = 'UTF-8';
if ($this->getConfig()->getOption('suppress_errors')) {
libxml_clear_errors();
}
return $document;
}
/**
* Convert Children
*
* Recursive function to drill into the DOM and convert each node into Markdown from the inside out.
*
* Finds children of each node and convert those to #text nodes containing their Markdown equivalent,
* starting with the innermost element and working up to the outermost element.
*
* @param ElementInterface $element
*/
private function convertChildren(ElementInterface $element)
{
// Don't convert HTML code inside <code> and <pre> blocks to Markdown - that should stay as HTML
// except if the current node is a code tag, which needs to be converted by the CodeConverter.
if ($element->isDescendantOf(array('pre', 'code')) && $element->getTagName() !== 'code') {
return;
}
// If the node has children, convert those to Markdown first
if ($element->hasChildren()) {
foreach ($element->getChildren() as $child) {
$this->convertChildren($child);
}
}
// Now that child nodes have been converted, convert the original node
$markdown = $this->convertToMarkdown($element);
// Create a DOM text node containing the Markdown equivalent of the original node
// Replace the old $node e.g. '<h3>Title</h3>' with the new $markdown_node e.g. '### Title'
$element->setFinalMarkdown($markdown);
}
/**
* Convert to Markdown
*
* Converts an individual node into a #text node containing a string of its Markdown equivalent.
*
* Example: An <h3> node with text content of 'Title' becomes a text node with content of '### Title'
*
* @param ElementInterface $element
*
* @return string The converted HTML as Markdown
*/
protected function convertToMarkdown(ElementInterface $element)
{
$tag = $element->getTagName();
// Strip nodes named in remove_nodes
$tags_to_remove = explode(' ', $this->getConfig()->getOption('remove_nodes'));
if (in_array($tag, $tags_to_remove)) {
return false;
}
$converter = $this->environment->getConverterByTag($tag);
return $converter->convert($element);
}
/**
* @param string $markdown
*
* @return string
*/
protected function sanitize($markdown)
{
$markdown = html_entity_decode($markdown, ENT_QUOTES, 'UTF-8');
$markdown = preg_replace('/<!DOCTYPE [^>]+>/', '', $markdown); // Strip doctype declaration
$markdown = trim($markdown); // Remove blank spaces at the beggining of the html
/*
* Removing unwanted tags. Tags should be added to the array in the order they are expected.
* XML, html and body opening tags should be in that order. Same case with closing tags
*/
$unwanted = array('<?xml encoding="UTF-8">', '<html>', '</html>', '<body>', '</body>', '<head>', '</head>', '
');
foreach ($unwanted as $tag) {
if (strpos($tag, '/') === false) {
// Opening tags
if (strpos($markdown, $tag) === 0) {
$markdown = substr($markdown, strlen($tag));
}
} else {
// Closing tags
if (strpos($markdown, $tag) === strlen($markdown) - strlen($tag)) {
$markdown = substr($markdown, 0, -strlen($tag));
}
}
}
return trim($markdown, "\n\r\0\x0B");
}
}
