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<?php
/**
* This class provides functions for converting CSS styles into inline style attributes in your HTML code.
*
* For more information, please see the README.md file.
*
* @version 1.0.0
*
* @author Cameron Brooks
* @author Jaime Prado
* @author Oliver Klee <typo3-coding@oliverklee.de>
* @author Roman Ožana <ozana@omdesign.cz>
*/
// @codingStandardsIgnoreFile
class Emogrifier
{
/**
* @var int
*/
const CACHE_KEY_CSS = 0;
/**
* @var int
*/
const CACHE_KEY_SELECTOR = 1;
/**
* @var int
*/
const CACHE_KEY_XPATH = 2;
/**
* @var int
*/
const CACHE_KEY_CSS_DECLARATIONS_BLOCK = 3;
/**
* @var int
*/
const CACHE_KEY_COMBINED_STYLES = 4;
/**
* for calculating nth-of-type and nth-child selectors
*
* @var int
*/
const INDEX = 0;
/**
* for calculating nth-of-type and nth-child selectors
*
* @var int
*/
const MULTIPLIER = 1;
/**
* @var string
*/
const ID_ATTRIBUTE_MATCHER = '/(\\w+)?\\#([\\w\\-]+)/';
/**
* @var string
*/
const CLASS_ATTRIBUTE_MATCHER = '/(\\w+|[\\*\\]])?((\\.[\\w\\-]+)+)/';
/**
* @var string
*/
const CONTENT_TYPE_META_TAG = '<meta http-equiv="Content-Type" content="text/html; charset=utf-8">';
/**
* @var string
*/
const DEFAULT_DOCUMENT_TYPE = '<!DOCTYPE html>';
/**
* @var string
*/
private $html = '';
/**
* @var string
*/
private $css = '';
/**
* @var bool[]
*/
private $excludedSelectors = array();
/**
* @var string[]
*/
private $unprocessableHtmlTags = array( 'wbr' );
/**
* @var bool[]
*/
private $allowedMediaTypes = array( 'all' => true, 'screen' => true, 'print' => true );
/**
* @var array[]
*/
private $caches = array(
self::CACHE_KEY_CSS => array(),
self::CACHE_KEY_SELECTOR => array(),
self::CACHE_KEY_XPATH => array(),
self::CACHE_KEY_CSS_DECLARATIONS_BLOCK => array(),
self::CACHE_KEY_COMBINED_STYLES => array(),
);
/**
* the visited nodes with the XPath paths as array keys
*
* @var DoMElement[]
*/
private $visitedNodes = array();
/**
* the styles to apply to the nodes with the XPath paths as array keys for the outer array
* and the attribute names/values as key/value pairs for the inner array
*
* @var array[]
*/
private $styleAttributesForNodes = array();
/**
* Determines whether the "style" attributes of tags in the the HTML passed to this class should be preserved.
* If set to false, the value of the style attributes will be discarded.
*
* @var bool
*/
private $isInlineStyleAttributesParsingEnabled = true;
/**
* Determines whether the <style> blocks in the HTML passed to this class should be parsed.
*
* If set to true, the <style> blocks will be removed from the HTML and their contents will be applied to the HTML
* via inline styles.
*
* If set to false, the <style> blocks will be left as they are in the HTML.
*
* @var bool
*/
private $isStyleBlocksParsingEnabled = true;
/**
* Determines whether elements with the `display: none` property are
* removed from the DOM.
*
* @var bool
*/
private $shouldKeepInvisibleNodes = true;
public static $_media = '';
/**
* The constructor.
*
* @param string $html the HTML to emogrify, must be UTF-8-encoded
* @param string $css the CSS to merge, must be UTF-8-encoded
*/
public function __construct( $html = '', $css = '' ) {
$this->setHtml($html);
$this->setCss($css);
}
/**
* The destructor.
*/
public function __destruct() {
$this->purgeVisitedNodes();
}
/**
* Sets the HTML to emogrify.
*
* @param string $html the HTML to emogrify, must be UTF-8-encoded
*
* @return void
*/
public function setHtml( $html ) {
$this->html = $html;
}
/**
* Sets the CSS to merge with the HTML.
*
* @param string $css the CSS to merge, must be UTF-8-encoded
*
* @return void
*/
public function setCss( $css ) {
$this->css = $css;
}
/**
* Applies $this->css to $this->html and returns the HTML with the CSS
* applied.
*
* This method places the CSS inline.
*
* @return string
*
* @throws BadMethodCallException
*/
public function emogrify() {
if ( $this->html === '' ) {
throw new BadMethodCallException('Please set some HTML first before calling emogrify.', 1390393096);
}
self::$_media = ''; // reset
$xmlDocument = $this->createXmlDocument();
$this->process($xmlDocument);
return $xmlDocument->saveHTML();
}
/**
* Applies $this->css to $this->html and returns only the HTML content
* within the <body> tag.
*
* This method places the CSS inline.
*
* @return string
*
* @throws BadMethodCallException
*/
public function emogrifyBodyContent() {
if ( $this->html === '' ) {
throw new BadMethodCallException('Please set some HTML first before calling emogrify.', 1390393096);
}
$xmlDocument = $this->createXmlDocument();
$this->process($xmlDocument);
$innerDocument = new DoMDocument();
foreach ( $xmlDocument->documentElement->getElementsByTagName('body')->item(0)->childNodes as $childNode ) {
$innerDocument->appendChild($innerDocument->importNode($childNode, true));
}
return $innerDocument->saveHTML();
}
/**
* Applies $this->css to $xmlDocument.
*
* This method places the CSS inline.
*
* @param DoMDocument $xmlDocument
*
* @return void
*/
protected function process( DoMDocument $xmlDocument ) {
$xpath = new DoMXPath($xmlDocument);
$this->clearAllCaches();
// Before be begin processing the CSS file, parse the document and normalize all existing CSS attributes.
// This changes 'DISPLAY: none' to 'display: none'.
// We wouldn't have to do this if DOMXPath supported XPath 2.0.
// Also store a reference of nodes with existing inline styles so we don't overwrite them.
$this->purgeVisitedNodes();
$nodesWithStyleAttributes = $xpath->query('//*[@style]');
if ( $nodesWithStyleAttributes !== false ) {
/** @var DoMElement $node */
foreach ( $nodesWithStyleAttributes as $node ) {
if ( $this->isInlineStyleAttributesParsingEnabled ) {
$this->normalizeStyleAttributes($node);
} else {
$node->removeAttribute('style');
}
}
}
// grab any existing style blocks from the html and append them to the existing CSS
// (these blocks should be appended so as to have precedence over conflicting styles in the existing CSS)
$allCss = $this->css;
if ( $this->isStyleBlocksParsingEnabled ) {
$allCss .= $this->getCssFromAllStyleNodes($xpath);
}
$cssParts = $this->splitCssAndMediaQuery($allCss);
$excludedNodes = $this->getNodesToExclude($xpath);
$cssRules = $this->parseCssRules($cssParts['css']);
foreach ( $cssRules as $cssRule ) {
// query the body for the xpath selector
$nodesMatchingCssSelectors = $xpath->query($this->translateCssToXpath($cssRule['selector']));
// ignore invalid selectors
if ( $nodesMatchingCssSelectors === false ) {
continue;
}
/** @var DoMElement $node */
foreach ( $nodesMatchingCssSelectors as $node ) {
if ( in_array($node, $excludedNodes, true) ) {
continue;
}
// if it has a style attribute, get it, process it, and append (overwrite) new stuff
if ( $node->hasAttribute('style') ) {
// break it up into an associative array
$oldStyleDeclarations = $this->parseCssDeclarationsBlock($node->getAttribute('style'));
} else {
$oldStyleDeclarations = array();
}
$newStyleDeclarations = $this->parseCssDeclarationsBlock($cssRule['declarationsBlock']);
$node->setAttribute(
'style',
$this->generateStyleStringFromDeclarationsArrays($oldStyleDeclarations, $newStyleDeclarations)
);
}
}
if ( $this->isInlineStyleAttributesParsingEnabled ) {
$this->fillStyleAttributesWithMergedStyles();
}
if ( $this->shouldKeepInvisibleNodes ) {
$this->removeInvisibleNodes($xpath);
}
$this->copyCssWithMediaToStyleNode($xmlDocument, $xpath, $cssParts['media']);
}
/**
* Extracts and parses the individual rules from a CSS string.
*
* @param string $css a string of raw CSS code
*
* @return string[][] an array of string sub-arrays with the keys
* "selector" (the CSS selector(s), e.g., "*" or "h1"),
* "declarationsBLock" (the semicolon-separated CSS declarations for that selector(s),
* e.g., "color: red; height: 4px;"),
* and "line" (the line number e.g. 42)
*/
private function parseCssRules( $css ) {
$cssKey = md5($css);
if ( ! isset($this->caches[ self::CACHE_KEY_CSS ][ $cssKey ]) ) {
// process the CSS file for selectors and definitions
preg_match_all('/(?:^|[\\s^{}]*)([^{]+){([^}]*)}/mis', $css, $matches, PREG_SET_ORDER);
$cssRules = array();
/** @var string[] $cssRule */
foreach ( $matches as $key => $cssRule ) {
$cssDeclaration = trim($cssRule[2]);
if ( $cssDeclaration === '' ) {
continue;
}
$selectors = explode(',', $cssRule[1]);
foreach ( $selectors as $selector ) {
// don't process pseudo-elements and behavioral (dynamic) pseudo-classes;
// only allow structural pseudo-classes
if ( strpos($selector, ':') !== false && ! preg_match('/:\\S+\\-(child|type\\()/i', $selector) ) {
continue;
}
$cssRules[] = array(
'selector' => trim($selector),
'declarationsBlock' => $cssDeclaration,
// keep track of where it appears in the file, since order is important
'line' => $key,
);
}
}
usort($cssRules, array( $this, 'sortBySelectorPrecedence' ) );
$this->caches[ self::CACHE_KEY_CSS ][ $cssKey ] = $cssRules;
}
return $this->caches[ self::CACHE_KEY_CSS ][ $cssKey ];
}
/**
* Disables the parsing of inline styles.
*
* @return void
*/
public function disableInlineStyleAttributesParsing() {
$this->isInlineStyleAttributesParsingEnabled = false;
}
/**
* Disables the parsing of <style> blocks.
*
* @return void
*/
public function disableStyleBlocksParsing() {
$this->isStyleBlocksParsingEnabled = false;
}
/**
* Disables the removal of elements with `display: none` properties.
*
* @return void
*/
public function disableInvisibleNodeRemoval() {
$this->shouldKeepInvisibleNodes = false;
}
/**
* Clears all caches.
*
* @return void
*/
private function clearAllCaches() {
$this->clearCache(self::CACHE_KEY_CSS);
$this->clearCache(self::CACHE_KEY_SELECTOR);
$this->clearCache(self::CACHE_KEY_XPATH);
$this->clearCache(self::CACHE_KEY_CSS_DECLARATIONS_BLOCK);
$this->clearCache(self::CACHE_KEY_COMBINED_STYLES);
}
/**
* Clears a single cache by key.
*
* @param int $key the cache key, must be CACHE_KEY_CSS, CACHE_KEY_SELECTOR, CACHE_KEY_XPATH
* or CACHE_KEY_CSS_DECLARATION_BLOCK
*
* @return void
*
* @throws \InvalidArgumentException
*/
private function clearCache( $key ) {
$allowedCacheKeys = array(
self::CACHE_KEY_CSS,
self::CACHE_KEY_SELECTOR,
self::CACHE_KEY_XPATH,
self::CACHE_KEY_CSS_DECLARATIONS_BLOCK,
self::CACHE_KEY_COMBINED_STYLES,
);
if ( ! in_array($key, $allowedCacheKeys, true) ) {
throw new InvalidArgumentException('Invalid cache key: ' . $key, 1391822035);
}
$this->caches[ $key ] = array();
}
/**
* Purges the visited nodes.
*
* @return void
*/
private function purgeVisitedNodes() {
$this->visitedNodes = array();
$this->styleAttributesForNodes = array();
}
/**
* Marks a tag for removal.
*
* There are some HTML tags that DOMDocument cannot process, and it will throw an error if it encounters them.
* In particular, DOMDocument will complain if you try to use HTML5 tags in an XHTML document.
*
* Note: The tags will not be removed if they have any content.
*
* @param string $tagName the tag name, e.g., "p"
*
* @return void
*/
public function addUnprocessableHtmlTag( $tagName ) {
$this->unprocessableHtmlTags[] = $tagName;
}
/**
* Drops a tag from the removal list.
*
* @param string $tagName the tag name, e.g., "p"
*
* @return void
*/
public function removeUnprocessableHtmlTag( $tagName ) {
$key = array_search($tagName, $this->unprocessableHtmlTags, true);
if ( $key !== false ) {
unset($this->unprocessableHtmlTags[ $key ]);
}
}
/**
* Marks a media query type to keep.
*
* @param string $mediaName the media type name, e.g., "braille"
*
* @return void
*/
public function addAllowedMediaType( $mediaName ) {
$this->allowedMediaTypes[ $mediaName ] = true;
}
/**
* Drops a media query type from the allowed list.
*
* @param string $mediaName the tag name, e.g., "braille"
*
* @return void
*/
public function removeAllowedMediaType( $mediaName ) {
if ( isset($this->allowedMediaTypes[ $mediaName ]) ) {
unset($this->allowedMediaTypes[ $mediaName ]);
}
}
/**
* Adds a selector to exclude nodes from emogrification.
*
* Any nodes that match the selector will not have their style altered.
*
* @param string $selector the selector to exclude, e.g., ".editor"
*
* @return void
*/
public function addExcludedSelector( $selector ) {
$this->excludedSelectors[ $selector ] = true;
}
/**
* No longer excludes the nodes matching this selector from emogrification.
*
* @param string $selector the selector to no longer exclude, e.g., ".editor"
*
* @return void
*/
public function removeExcludedSelector( $selector ) {
if ( isset($this->excludedSelectors[ $selector ]) ) {
unset($this->excludedSelectors[ $selector ]);
}
}
/**
* This removes styles from your email that contain display:none.
* We need to look for display:none, but we need to do a case-insensitive search. Since DOMDocument only
* supports XPath 1.0, lower-case() isn't available to us. We've thus far only set attributes to lowercase,
* not attribute values. Consequently, we need to translate() the letters that would be in 'NONE' ("NOE")
* to lowercase.
*
* @param DoMXPath $xpath
*
* @return void
*/
private function removeInvisibleNodes( DoMXPath $xpath ) {
$nodesWithStyleDisplayNone = $xpath->query(
'//*[contains(translate(translate(@style," ",""),"NOE","noe"),"display:none")]'
);
if ( $nodesWithStyleDisplayNone->length === 0 ) {
return;
}
// The checks on parentNode and is_callable below ensure that if we've deleted the parent node,
// we don't try to call removeChild on a nonexistent child node
/** @var DoMNode $node */
foreach ( $nodesWithStyleDisplayNone as $node ) {
if ( $node->parentNode && is_callable( array( $node->parentNode, 'removeChild' ) ) ) {
$node->parentNode->removeChild($node);
}
}
}
private function normalizeStyleAttributes_callback( $m ) {
return strtolower( $m[0] );
}
/**
* Normalizes the value of the "style" attribute and saves it.
*
* @param DoMElement $node
*
* @return void
*/
private function normalizeStyleAttributes( DoMElement $node ) {
$normalizedOriginalStyle = preg_replace_callback(
'/[A-z\\-]+(?=\\:)/S',
array( $this, 'normalizeStyleAttributes_callback' ),
$node->getAttribute('style')
);
// in order to not overwrite existing style attributes in the HTML, we
// have to save the original HTML styles
$nodePath = $node->getNodePath();
if ( ! isset($this->styleAttributesForNodes[ $nodePath ]) ) {
$this->styleAttributesForNodes[ $nodePath ] = $this->parseCssDeclarationsBlock($normalizedOriginalStyle);
$this->visitedNodes[ $nodePath ] = $node;
}
$node->setAttribute('style', $normalizedOriginalStyle);
}
/**
* Merges styles from styles attributes and style nodes and applies them to the attribute nodes
*
* @return void
*/
private function fillStyleAttributesWithMergedStyles() {
foreach ( $this->styleAttributesForNodes as $nodePath => $styleAttributesForNode ) {
$node = $this->visitedNodes[ $nodePath ];
$currentStyleAttributes = $this->parseCssDeclarationsBlock($node->getAttribute('style'));
$node->setAttribute(
'style',
$this->generateStyleStringFromDeclarationsArrays(
$currentStyleAttributes,
$styleAttributesForNode
)
);
}
}
/**
* This method merges old or existing name/value array with new name/value array
* and then generates a string of the combined style suitable for placing inline.
* This becomes the single point for CSS string generation allowing for consistent
* CSS output no matter where the CSS originally came from.
*
* @param string[] $oldStyles
* @param string[] $newStyles
*
* @return string
*/
private function generateStyleStringFromDeclarationsArrays( array $oldStyles, array $newStyles ) {
$combinedStyles = array_merge($oldStyles, $newStyles);
$cacheKey = serialize( $combinedStyles );
if ( isset($this->caches[ self::CACHE_KEY_COMBINED_STYLES ][ $cacheKey ]) ) {
return $this->caches[ self::CACHE_KEY_COMBINED_STYLES ][ $cacheKey ];
}
foreach ( $oldStyles as $attributeName => $attributeValue ) {
if ( isset($newStyles[ $attributeName ]) && strtolower(substr($attributeValue, -10)) === '!important' ) {
$combinedStyles[ $attributeName ] = $attributeValue;
}
}
$style = '';
foreach ( $combinedStyles as $attributeName => $attributeValue ) {
$style .= strtolower(trim($attributeName)) . ': ' . trim($attributeValue) . '; ';
}
$trimmedStyle = rtrim($style);
$this->caches[ self::CACHE_KEY_COMBINED_STYLES ][ $cacheKey ] = $trimmedStyle;
return $trimmedStyle;
}
/**
* Applies $css to $xmlDocument, limited to the media queries that actually apply to the document.
*
* @param DoMDocument $xmlDocument the document to match against
* @param DoMXPath $xpath
* @param string $css a string of CSS
*
* @return void
*/
private function copyCssWithMediaToStyleNode( DoMDocument $xmlDocument, DoMXPath $xpath, $css ) {
if ( $css === '' ) {
return;
}
$mediaQueriesRelevantForDocument = array();
foreach ( $this->extractMediaQueriesFromCss($css) as $mediaQuery ) {
foreach ( $this->parseCssRules($mediaQuery['css']) as $selector ) {
if ( $this->existsMatchForCssSelector($xpath, $selector['selector']) ) {
$mediaQueriesRelevantForDocument[] = $mediaQuery['query'];
break;
}
}
}
$this->addStyleElementToDocument($xmlDocument, implode($mediaQueriesRelevantForDocument));
}
/**
* Extracts the media queries from $css.
*
* @param string $css
*
* @return string[][] numeric array with string sub-arrays with the keys "css" and "query"
*/
private function extractMediaQueriesFromCss( $css ) {
preg_match_all('#(?<query>@media[^{]*\\{(?<css>(.*?)\\})(\\s*)\\})#s', $css, $mediaQueries);
$result = array();
foreach ( array_keys($mediaQueries['css']) as $key ) {
$result[] = array(
'css' => $mediaQueries['css'][ $key ],
'query' => $mediaQueries['query'][ $key ],
);
}
return $result;
}
/**
* Checks whether there is at least one matching element for $cssSelector.
*
* @param DoMXPath $xpath
* @param string $cssSelector
*
* @return bool
*/
private function existsMatchForCssSelector( DoMXPath $xpath, $cssSelector ) {
$nodesMatchingSelector = $xpath->query($this->translateCssToXpath($cssSelector));
return $nodesMatchingSelector !== false && $nodesMatchingSelector->length !== 0;
}
/**
* Returns CSS content.
*
* @param DoMXPath $xpath
*
* @return string
*/
private function getCssFromAllStyleNodes( DoMXPath $xpath ) {
$styleNodes = $xpath->query('//style');
if ( $styleNodes === false ) {
return '';
}
$css = '';
/** @var DoMNode $styleNode */
foreach ( $styleNodes as $styleNode ) {
$css .= "\n\n" . $styleNode->nodeValue;
$styleNode->parentNode->removeChild($styleNode);
}
return $css;
}
/**
* Adds a style element with $css to $document.
*
* This method is protected to allow overriding.
*
* @see https://github.com/jjriv/emogrifier/issues/103
*
* @param DoMDocument $document
* @param string $css
*
* @return void
*/
protected function addStyleElementToDocument( DoMDocument $document, $css ) {
$styleElement = $document->createElement('style', $css);
$styleAttribute = $document->createAttribute('type');
$styleAttribute->value = 'text/css';
$styleElement->appendChild($styleAttribute);
$head = $this->getOrCreateHeadElement($document);
$head->appendChild($styleElement);
}
/**
* Returns the existing or creates a new head element in $document.
*
* @param DoMDocument $document
*
* @return DoMNode the head element
*/
private function getOrCreateHeadElement( DoMDocument $document ) {
$head = $document->getElementsByTagName('head')->item(0);
if ( $head === null ) {
$head = $document->createElement('head');
$html = $document->getElementsByTagName('html')->item(0);
$html->insertBefore($head, $document->getElementsByTagName('body')->item(0));
}
return $head;
}
private function splitCssAndMediaQuery_callback() {
}
/**
* Splits input CSS code to an array where:
*
* - key "css" will be contains clean CSS code.
* - key "media" will be contains all valuable media queries.
*
* Example:
*
* The CSS code.
*
* "@import "file.css"; h1 { color:red; } @media { h1 {}} @media tv { h1 {}}"
*
* will be parsed into the following array:
*
* "css" => "h1 { color:red; }"
* "media" => "@media { h1 {}}"
*
* @param string $css
* @return array
*/
private function splitCssAndMediaQuery( $css ) {
$css = preg_replace_callback( '#@media\\s+(?:only\\s)?(?:[\\s{\(]|screen|all)\\s?[^{]+{.*}\\s*}\\s*#misU', array( $this, '_media_concat' ), $css );
// filter the CSS
$search = array(
// get rid of css comment code
'/\\/\\*.*\\*\\//sU',
// strip out any import directives
'/^\\s*@import\\s[^;]+;/misU',
// strip remains media enclosures
'/^\\s*@media\\s[^{]+{(.*)}\\s*}\\s/misU',
);
$replace = array(
'',
'',
'',
);
// clean CSS before output
$css = preg_replace($search, $replace, $css);
return array( 'css' => $css, 'media' => self::$_media );
}
private function _media_concat( $matches ) {
self::$_media .= $matches[0];
}
/**
* Creates a DOMDocument instance with the current HTML.
*
* @return DoMDocument
*/
private function createXmlDocument() {
$xmlDocument = new DoMDocument;
$xmlDocument->encoding = 'UTF-8';
$xmlDocument->strictErrorChecking = false;
$xmlDocument->formatOutput = true;
$libXmlState = libxml_use_internal_errors(true);
$xmlDocument->loadHTML($this->getUnifiedHtml());
libxml_clear_errors();
libxml_use_internal_errors($libXmlState);
$xmlDocument->normalizeDocument();
return $xmlDocument;
}
/**
* Returns the HTML with the unprocessable HTML tags removed and
* with added document type and Content-Type meta tag if needed.
*
* @return string the unified HTML
*
* @throws BadMethodCallException
*/
private function getUnifiedHtml() {
$htmlWithoutUnprocessableTags = $this->removeUnprocessableTags($this->html);
$htmlWithDocumentType = $this->ensureDocumentType($htmlWithoutUnprocessableTags);
return $this->addContentTypeMetaTag($htmlWithDocumentType);
}
/**
* Removes the unprocessable tags from $html (if this feature is enabled).
*
* @param string $html
*
* @return string the reworked HTML with the unprocessable tags removed
*/
private function removeUnprocessableTags( $html ) {
if ( empty($this->unprocessableHtmlTags) ) {
return $html;
}
$unprocessableHtmlTags = implode('|', $this->unprocessableHtmlTags);
return preg_replace(
'/<\\/?(' . $unprocessableHtmlTags . ')[^>]*>/i',
'',
$html
);
}
/**
* Makes sure that the passed HTML has a document type.
*
* @param string $html
*
* @return string HTML with document type
*/
private function ensureDocumentType( $html ) {
$hasDocumentType = stripos($html, '<!DOCTYPE') !== false;
if ( $hasDocumentType ) {
return $html;
}
return self::DEFAULT_DOCUMENT_TYPE . $html;
}
/**
* Adds a Content-Type meta tag for the charset.
*
* @param string $html
*
* @return string the HTML with the meta tag added
*/
private function addContentTypeMetaTag( $html ) {
$hasContentTypeMetaTag = stristr($html, 'Content-Type') !== false;
if ( $hasContentTypeMetaTag ) {
return $html;
}
// We are trying to insert the meta tag to the right spot in the DOM.
// If we just prepended it to the HTML, we would lose attributes set to the HTML tag.
$hasHeadTag = stripos($html, '<head') !== false;
$hasHtmlTag = stripos($html, '<html') !== false;
if ( $hasHeadTag ) {
$reworkedHtml = preg_replace('/<head(.*?)>/i', '<head$1>' . self::CONTENT_TYPE_META_TAG, $html);
} elseif ( $hasHtmlTag ) {
$reworkedHtml = preg_replace(
'/<html(.*?)>/i',
'<html$1><head>' . self::CONTENT_TYPE_META_TAG . '</head>',
$html
);
} else {
$reworkedHtml = self::CONTENT_TYPE_META_TAG . $html;
}
return $reworkedHtml;
}
/**
* @param string[] $a
* @param string[] $b
*
* @return int
*/
private function sortBySelectorPrecedence( array $a, array $b ) {
$precedenceA = $this->getCssSelectorPrecedence($a['selector']);
$precedenceB = $this->getCssSelectorPrecedence($b['selector']);
// We want these sorted in ascending order so selectors with lesser precedence get processed first and
// selectors with greater precedence get sorted last.
$precedenceForEquals = ($a['line'] < $b['line'] ? -1 : 1);
$precedenceForNotEquals = ($precedenceA < $precedenceB ? -1 : 1);
return ($precedenceA === $precedenceB) ? $precedenceForEquals : $precedenceForNotEquals;
}
/**
* @param string $selector
*
* @return int
*/
private function getCssSelectorPrecedence( $selector ) {
$selectorKey = md5($selector);
if ( ! isset($this->caches[ self::CACHE_KEY_SELECTOR ][ $selectorKey ]) ) {
$precedence = 0;
$value = 100;
// ids: worth 100, classes: worth 10, elements: worth 1
$search = array( '\\#','\\.','' );
foreach ( $search as $s ) {
if ( trim($selector) === '' ) {
break;
}
$number = 0;
$selector = preg_replace('/' . $s . '\\w+/', '', $selector, -1, $number);
$precedence += ($value * $number);
$value /= 10;
}
$this->caches[ self::CACHE_KEY_SELECTOR ][ $selectorKey ] = $precedence;
}
return $this->caches[ self::CACHE_KEY_SELECTOR ][ $selectorKey ];
}
private function translateCssToXpath_callback( $matches ) {
return strtolower($matches[0]);
}
/**
* Maps a CSS selector to an XPath query string.
*
* @see http://plasmasturm.org/log/444/
*
* @param string $cssSelector a CSS selector
*
* @return string the corresponding XPath selector
*/
private function translateCssToXpath( $cssSelector ) {
$paddedSelector = ' ' . $cssSelector . ' ';
$lowercasePaddedSelector = preg_replace_callback(
'/\\s+\\w+\\s+/',
array( $this, 'translateCssToXpath_callback' ),
$paddedSelector
);
$trimmedLowercaseSelector = trim($lowercasePaddedSelector);
$xpathKey = md5($trimmedLowercaseSelector);
if ( ! isset($this->caches[ self::CACHE_KEY_XPATH ][ $xpathKey ]) ) {
$cssSelectorMatches = array(
'child' => '/\\s+>\\s+/',
'adjacent sibling' => '/\\s+\\+\\s+/',
'descendant' => '/\\s+/',
':first-child' => '/([^\\/]+):first-child/i',
':last-child' => '/([^\\/]+):last-child/i',
'attribute only' => '/^\\[(\\w+|\\w+\\=[\'"]?\\w+[\'"]?)\\]/',
'attribute' => '/(\\w)\\[(\\w+)\\]/',
'exact attribute' => '/(\\w)\\[(\\w+)\\=[\'"]?(\\w+)[\'"]?\\]/',
);
$xPathReplacements = array(
'child' => '/',
'adjacent sibling' => '/following-sibling::*[1]/self::',
'descendant' => '//',
':first-child' => '\\1/*[1]',
':last-child' => '\\1/*[last()]',
'attribute only' => '*[@\\1]',
'attribute' => '\\1[@\\2]',
'exact attribute' => '\\1[@\\2="\\3"]',
);
$roughXpath = '//' . preg_replace($cssSelectorMatches, $xPathReplacements, $trimmedLowercaseSelector);
$xpathWithIdAttributeMatchers = preg_replace_callback(
self::ID_ATTRIBUTE_MATCHER,
array( $this, 'matchIdAttributes' ),
$roughXpath
);
$xpathWithIdAttributeAndClassMatchers = preg_replace_callback(
self::CLASS_ATTRIBUTE_MATCHER,
array( $this, 'matchClassAttributes' ),
$xpathWithIdAttributeMatchers
);
// Advanced selectors are going to require a bit more advanced emogrification.
// When we required PHP 5.3, we could do this with closures.
$xpathWithIdAttributeAndClassMatchers = preg_replace_callback(
'/([^\\/]+):nth-child\\(\\s*(odd|even|[+\\-]?\\d|[+\\-]?\\d?n(\\s*[+\\-]\\s*\\d)?)\\s*\\)/i',
array( $this, 'translateNthChild' ),
$xpathWithIdAttributeAndClassMatchers
);
$finalXpath = preg_replace_callback(
'/([^\\/]+):nth-of-type\\(\s*(odd|even|[+\\-]?\\d|[+\\-]?\\d?n(\\s*[+\\-]\\s*\\d)?)\\s*\\)/i',
array( $this, 'translateNthOfType' ),
$xpathWithIdAttributeAndClassMatchers
);
$this->caches[ self::CACHE_KEY_SELECTOR ][ $xpathKey ] = $finalXpath;
}
return $this->caches[ self::CACHE_KEY_SELECTOR ][ $xpathKey ];
}
/**
* @param string[] $match
*
* @return string
*/
private function matchIdAttributes( array $match ) {
return ($match[1] !== '' ? $match[1] : '*') . '[@id="' . $match[2] . '"]';
}
/**
* @param string[] $match
*
* @return string
*/
private function matchClassAttributes( array $match ) {
return ($match[1] !== '' ? $match[1] : '*') . '[contains(concat(" ",@class," "),concat(" ","' .
implode(
'"," "))][contains(concat(" ",@class," "),concat(" ","',
explode('.', substr($match[2], 1))
) . '"," "))]';
}
/**
* @param string[] $match
*
* @return string
*/
private function translateNthChild( array $match ) {
$parseResult = $this->parseNth($match);
if ( isset($parseResult[ self::MULTIPLIER ]) ) {
if ( $parseResult[ self::MULTIPLIER ] < 0 ) {
$parseResult[ self::MULTIPLIER ] = abs($parseResult[ self::MULTIPLIER ]);
$xPathExpression = sprintf(
'*[(last() - position()) mod %u = %u]/self::%s',
$parseResult[ self::MULTIPLIER ],
$parseResult[ self::INDEX ],
$match[1]
);
} else {
$xPathExpression = sprintf(
'*[position() mod %u = %u]/self::%s',
$parseResult[ self::MULTIPLIER ],
$parseResult[ self::INDEX ],
$match[1]
);
}
} else {
$xPathExpression = sprintf('*[%u]/self::%s', $parseResult[ self::INDEX ], $match[1]);
}
return $xPathExpression;
}
/**
* @param string[] $match
*
* @return string
*/
private function translateNthOfType( array $match ) {
$parseResult = $this->parseNth($match);
if ( isset($parseResult[ self::MULTIPLIER ]) ) {
if ( $parseResult[ self::MULTIPLIER ] < 0 ) {
$parseResult[ self::MULTIPLIER ] = abs($parseResult[ self::MULTIPLIER ]);
$xPathExpression = sprintf(
'%s[(last() - position()) mod %u = %u]',
$match[1],
$parseResult[ self::MULTIPLIER ],
$parseResult[ self::INDEX ]
);
} else {
$xPathExpression = sprintf(
'%s[position() mod %u = %u]',
$match[1],
$parseResult[ self::MULTIPLIER ],
$parseResult[ self::INDEX ]
);
}
} else {
$xPathExpression = sprintf('%s[%u]', $match[1], $parseResult[ self::INDEX ]);
}
return $xPathExpression;
}
/**
* @param string[] $match
*
* @return int[]
*/
private function parseNth( array $match ) {
if ( in_array(strtolower($match[2]), array( 'even', 'odd' ), true) ) {
// we have "even" or "odd"
$index = strtolower($match[2]) === 'even' ? 0 : 1;
return array( self::MULTIPLIER => 2, self::INDEX => $index );
}
if ( stripos($match[2], 'n') === false ) {
// if there is a multiplier
$index = (int) str_replace(' ', '', $match[2]);
return array( self::INDEX => $index );
}
if ( isset($match[3]) ) {
$multipleTerm = str_replace($match[3], '', $match[2]);
$index = (int) str_replace(' ', '', $match[3]);
} else {
$multipleTerm = $match[2];
$index = 0;
}
$multiplier = str_ireplace('n', '', $multipleTerm);
if ( $multiplier === '' ) {
$multiplier = 1;
} elseif ( $multiplier === '0' ) {
return array( self::INDEX => $index );
} else {
$multiplier = (int) $multiplier;
}
while ( $index < 0 ) {
$index += abs($multiplier);
}
return array( self::MULTIPLIER => $multiplier, self::INDEX => $index );
}
/**
* Parses a CSS declaration block into property name/value pairs.
*
* Example:
*
* The declaration block
*
* "color: #000; font-weight: bold;"
*
* will be parsed into the following array:
*
* "color" => "#000"
* "font-weight" => "bold"
*
* @param string $cssDeclarationsBlock the CSS declarations block without the curly braces, may be empty
*
* @return string[]
* the CSS declarations with the property names as array keys and the property values as array values
*/
private function parseCssDeclarationsBlock( $cssDeclarationsBlock ) {
if ( isset($this->caches[ self::CACHE_KEY_CSS_DECLARATIONS_BLOCK ][ $cssDeclarationsBlock ]) ) {
return $this->caches[ self::CACHE_KEY_CSS_DECLARATIONS_BLOCK ][ $cssDeclarationsBlock ];
}
$properties = array();
$declarations = preg_split('/;(?!base64|charset)/', $cssDeclarationsBlock);
foreach ( $declarations as $declaration ) {
$matches = array();
if ( ! preg_match('/^([A-Za-z\\-]+)\\s*:\\s*(.+)$/', trim($declaration), $matches) ) {
continue;
}
$propertyName = strtolower($matches[1]);
$propertyValue = $matches[2];
$properties[ $propertyName ] = $propertyValue;
}
$this->caches[ self::CACHE_KEY_CSS_DECLARATIONS_BLOCK ][ $cssDeclarationsBlock ] = $properties;
return $properties;
}
/**
* Find the nodes that are not to be emogrified.
*
* @param DoMXPath $xpath
*
* @return DoMElement[]
*/
private function getNodesToExclude( DoMXPath $xpath ) {
$excludedNodes = array();
foreach ( array_keys($this->excludedSelectors) as $selectorToExclude ) {
foreach ( $xpath->query($this->translateCssToXpath($selectorToExclude)) as $node ) {
$excludedNodes[] = $node;
}
}
return $excludedNodes;
}
}