loadHTML( '' . $content . '' );
libxml_clear_errors();
libxml_use_internal_errors( $libxml_previous_state );
if ( ! $result ) {
return false;
}
return $dom;
}
/**
* Return valid HTML content extracted from the DOMDocument passed as a parameter.
*
* @see Reciprocal function get_dom_from_content()
*
* @since 0.2
*
* @param DOMDocument $dom Represents an HTML document from which to extract HTML content.
*
* @return string Returns the HTML content represented in the DOMDocument
*/
public static function get_content_from_dom( $dom ) {
/**
* We only want children of the body tag, since we have a subset of HTML.
*/
$body = $dom->getElementsByTagName( 'body' )->item( 0 );
/**
* The DOMDocument may contain no body. In which case return nothing.
*/
if ( is_null( $body ) ) {
return '';
}
$out = '';
foreach ( $body->childNodes as $child_node ) {
$out .= self::get_content_from_dom_node( $dom, $child_node );
}
return $out;
}
/**
* Return valid HTML content extracted from the DOMNode passed as a parameter.
*
* @see Called by function get_content_from_dom()
*
* @since 0.6
*
* @param DOMDocument $dom Represents an HTML document.
* @param DOMNode $node Represents an HTML element of the $dom from which to extract HTML content.
* @return string Returns the HTML content represented in the DOMNode
*/
public static function get_content_from_dom_node( $dom, $node ) {
/**
* Self closing tags regex.
*
* @var string Regular expression to match self-closing tags
* that saveXML() has generated a closing tag for.
*/
static $self_closing_tags_regex;
/*
* Most AMP elements need closing tags. To force them, we cannot use
* saveHTML (node support is 5.3+) and LIBXML_NOEMPTYTAG results in
* issues with self-closing tags like `br` and `hr`. So, we're manually
* forcing closing tags.
*/
self::recursive_force_closing_tags( $dom, $node );
/*
* Cache this regex so we don't have to recreate it every call.
*/
if ( ! isset( $self_closing_tags_regex ) ) {
$self_closing_tags = implode( '|', self::get_self_closing_tags() );
$self_closing_tags_regex = "#>#i";
}
$html = $dom->saveXML( $node );
// Whitespace just causes unit tests to fail... so whitespace begone.
if ( '' === trim( $html ) ) {
return '';
}
/*
* Travis w/PHP 7.1 generates and vs. and , respectively.
* Travis w/PHP 7.x generates vs. . Etc.
* Seems like LIBXML_NOEMPTYTAG was passed, but as you can see it was not.
* This does not happen in my (@mikeschinkel) local testing, btw.
*/
$html = preg_replace( $self_closing_tags_regex, '/>', $html );
return $html;
}
/**
* Create a new node w/attributes (a DOMElement) and add to the passed DOMDocument.
*
* @since 0.2
*
* @param DOMDocument $dom A representation of an HTML document to add the new node to.
* @param string $tag A valid HTML element tag for the element to be added.
* @param string[] $attributes One of more valid attributes for the new node.
*
* @return DOMElement|false The DOMElement for the given $tag, or false on failure
*/
public static function create_node( $dom, $tag, $attributes ) {
$node = $dom->createElement( $tag );
self::add_attributes_to_node( $node, $attributes );
return $node;
}
/**
* Extract a DOMElement node's HTML element attributes and return as an array.
*
* @since 0.2
*
* @param DOMNode $node Represents an HTML element for which to extract attributes.
*
* @return string[] The attributes for the passed node, or an
* empty array if it has no attributes.
*/
public static function get_node_attributes_as_assoc_array( $node ) {
$attributes = array();
if ( ! $node->hasAttributes() ) {
return $attributes;
}
foreach ( $node->attributes as $attribute ) {
$attributes[ $attribute->nodeName ] = $attribute->nodeValue;
}
return $attributes;
}
/**
* Add one or more HTML element attributes to a node's DOMElement.
*
* @since 0.2
*
* @param DOMElement $node Represents an HTML element.
* @param string[] $attributes One or more attributes for the node's HTML element.
*/
public static function add_attributes_to_node( $node, $attributes ) {
foreach ( $attributes as $name => $value ) {
$node->setAttribute( $name, $value );
}
}
/**
* Determines if a DOMElement's node is empty or not..
*
* @since 0.2
*
* @param DOMElement $node Represents an HTML element.
* @return bool Returns true if the DOMElement has no child nodes and
* the textContent property of the DOMElement is empty;
* Otherwise it returns false.
*/
public static function is_node_empty( $node ) {
return false === $node->hasChildNodes() && empty( $node->textContent );
}
/**
* Forces HTML element closing tags given a DOMDocument and optional DOMElement
*
* @since 0.2
*
* @param DOMDocument $dom Represents HTML document on which to force closing tags.
* @param DOMElement $node Represents HTML element to start closing tags on.
* If not passed, defaults to first child of body.
*/
public static function recursive_force_closing_tags( $dom, $node = null ) {
if ( is_null( $node ) ) {
$node = $dom->getElementsByTagName( 'body' )->item( 0 );
}
if ( XML_ELEMENT_NODE !== $node->nodeType ) {
return;
}
if ( self::is_self_closing_tag( $node->nodeName ) ) {
/*
* Ensure there is no text content to accidentally force a child
*/
$node->textContent = null;
return;
}
if ( self::is_node_empty( $node ) ) {
$text_node = $dom->createTextNode( '' );
$node->appendChild( $text_node );
return;
}
$num_children = $node->childNodes->length;
for ( $i = $num_children - 1; $i >= 0; $i -- ) {
$child = $node->childNodes->item( $i );
self::recursive_force_closing_tags( $dom, $child );
}
}
/**
* Determines if an HTML element tag is validly a self-closing tag per W3C HTML5 specs.
*
* @since 0.2
*
* @param string $tag Tag.
* @return bool Returns true if a valid self-closing tag, false if not.
*/
private static function is_self_closing_tag( $tag ) {
return in_array( $tag, self::get_self_closing_tags(), true );
}
/**
* Returns array of self closing tags
*
* @since 0.6
*
* @return string[]
*/
private static function get_self_closing_tags() {
/*
* As this function is called a lot the static var
* prevents having to re-create the array every time.
*/
static $self_closing_tags;
if ( ! isset( $self_closing_tags ) ) {
/*
* https://www.w3.org/TR/html5/syntax.html#serializing-html-fragments
* Not all are valid AMP, but we include them for completeness.
*/
$self_closing_tags = array(
'area',
'base',
'basefont',
'bgsound',
'br',
'col',
'embed',
'frame',
'hr',
'img',
'input',
'keygen',
'link',
'meta',
'param',
'source',
'track',
'wbr',
);
}
return $self_closing_tags;
}
}