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woocommerce/includes/libraries/Emogrifier/CssInliner.php

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Update Emogrifier
2019-01-04 14:47:49 +00:00
<?php
namespace Pelago\Emogrifier;
use Symfony\Component\CssSelector\CssSelectorConverter;
use Symfony\Component\CssSelector\Exception\SyntaxErrorException;
/**
* This class provides functions for converting CSS styles into inline style attributes in your HTML code.
*
* For Emogrifier 3.0.0, this will be the successor to the \Pelago\Emogrifier class (which then will be deprecated).
*
* For more information, please see the README.md file.
*
* @internal This class currently is a new technology preview, and its API is still in flux. Don't use it in production.
*
* @author Cameron Brooks
* @author Jaime Prado
* @author Oliver Klee <github@oliverklee.de>
* @author Roman Ožana <ozana@omdesign.cz>
* @author Sander Kruger <s.kruger@invessel.com>
* @author Zoli Szabó <zoli.szabo+github@gmail.com>
*/
class CssInliner
{
/**
* @var int
*/
const CACHE_KEY_CSS = 0;
/**
* @var int
*/
const CACHE_KEY_SELECTOR = 1;
/**
* @var int
*/
const CACHE_KEY_CSS_DECLARATIONS_BLOCK = 2;
/**
* @var int
*/
const CACHE_KEY_COMBINED_STYLES = 3;
/**
* Regular expression component matching a static pseudo class in a selector, without the preceding ":",
* for which the applicable elements can be determined (by converting the selector to an XPath expression).
* (Contains alternation without a group and is intended to be placed within a capturing, non-capturing or lookahead
* group, as appropriate for the usage context.)
*
* @var string
*/
const PSEUDO_CLASS_MATCHER = '\\S+\\-(?:child|type\\()|not\\([[:ascii:]]*\\)';
/**
* @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 \DOMDocument
*/
protected $domDocument = null;
/**
* @var string
*/
private $css = '';
/**
* @var bool[]
*/
private $excludedSelectors = [];
/**
* @var string[]
*/
private $unprocessableHtmlTags = ['wbr'];
/**
* @var bool[]
*/
private $allowedMediaTypes = ['all' => true, 'screen' => true, 'print' => true];
/**
* @var mixed[]
*/
private $caches = [
self::CACHE_KEY_CSS => [],
self::CACHE_KEY_SELECTOR => [],
self::CACHE_KEY_CSS_DECLARATIONS_BLOCK => [],
self::CACHE_KEY_COMBINED_STYLES => [],
];
/**
* @var CssSelectorConverter
*/
private $cssSelectorConverter = null;
/**
* the visited nodes with the XPath paths as array keys
*
* @var \DOMElement[]
*/
private $visitedNodes = [];
/**
* 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 string[][]
*/
private $styleAttributesForNodes = [];
/**
* 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 $shouldRemoveInvisibleNodes = true;
/**
* For calculating selector precedence order.
* Keys are a regular expression part to match before a CSS name.
* Values are a multiplier factor per match to weight specificity.
*
* @var int[]
*/
private $selectorPrecedenceMatchers = [
// IDs: worth 10000
'\\#' => 10000,
// classes, attributes, pseudo-classes (not pseudo-elements) except `:not`: worth 100
'(?:\\.|\\[|(?<!:):(?!not\\())' => 100,
// elements (not attribute values or `:not`), pseudo-elements: worth 1
'(?:(?<![="\':\\w\\-])|::)' => 1,
];
/**
* Emogrifier will throw Exceptions when it encounters an error instead of silently ignoring them.
*
* @var bool
*/
private $debug = false;
/**
* @param string $unprocessedHtml raw HTML, must be UTF-encoded, must not be empty
*
* @throws \InvalidArgumentException if $unprocessedHtml is anything other than a non-empty string
*/
public function __construct($unprocessedHtml)
{
if (!\is_string($unprocessedHtml)) {
throw new \InvalidArgumentException('The provided HTML must be a string.', 1540403176);
}
if ($unprocessedHtml === '') {
throw new \InvalidArgumentException('The provided HTML must not be empty.', 1540403181);
}
$this->cssSelectorConverter = new CssSelectorConverter();
$this->setHtml($unprocessedHtml);
}
/**
* Sets the HTML to process.
*
* @param string $html the HTML to process, must be UTF-8-encoded
*
* @return void
*/
private function setHtml($html)
{
$this->createUnifiedDomDocument($html);
}
/**
* Provides access to the internal DOMDocument representation of the HTML in its current state.
*
* @return \DOMDocument
*/
public function getDomDocument()
{
return $this->domDocument;
}
/**
* 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;
}
/**
* Renders the normalized and processed HTML.
*
* @return string
*/
public function render()
{
return $this->domDocument->saveHTML();
}
/**
* Renders the content of the BODY element of the normalized and processed HTML.
*
* @return string
*/
public function renderBodyContent()
{
$bodyNodeHtml = $this->domDocument->saveHTML($this->getBodyElement());
return \str_replace(['<body>', '</body>'], '', $bodyNodeHtml);
}
/**
* Returns the BODY element.
*
* This method assumes that there always is a BODY element.
*
* @return \DOMElement
*/
private function getBodyElement()
{
return $this->domDocument->getElementsByTagName('body')->item(0);
}
/**
* Returns the HEAD element.
*
* This method assumes that there always is a HEAD element.
*
* @return \DOMElement
*/
private function getHeadElement()
{
return $this->domDocument->getElementsByTagName('head')->item(0);
}
/**
* Applies $this->css to the given HTML and returns the HTML with the CSS
* applied.
*
* This method places the CSS inline.
*
* @return string
*
* @throws SyntaxErrorException
*/
public function emogrify()
{
$this->process();
return $this->render();
}
/**
* Applies $this->css to the given HTML and returns only the HTML content
* within the <body> tag.
*
* This method places the CSS inline.
*
* @return string
*
* @throws SyntaxErrorException
*/
public function emogrifyBodyContent()
{
$this->process();
return $this->renderBodyContent();
}
/**
* Creates a DOM document from the given HTML and stores it in $this->domDocument.
*
* The DOM document will always have a BODY element and a document type.
*
* @param string $html
*
* @return void
*/
private function createUnifiedDomDocument($html)
{
$this->createRawDomDocument($html);
$this->ensureExistenceOfBodyElement();
}
/**
* Creates a DOMDocument instance from the given HTML and stores it in $this->domDocument.
*
* @param string $html
*
* @return void
*/
private function createRawDomDocument($html)
{
$domDocument = new \DOMDocument();
$domDocument->encoding = 'UTF-8';
$domDocument->strictErrorChecking = false;
$domDocument->formatOutput = true;
$libXmlState = \libxml_use_internal_errors(true);
$domDocument->loadHTML($this->prepareHtmlForDomConversion($html));
\libxml_clear_errors();
\libxml_use_internal_errors($libXmlState);
$domDocument->normalizeDocument();
$this->domDocument = $domDocument;
}
/**
* Returns the HTML with added document type and Content-Type meta tag if needed,
* ensuring that the HTML will be good for creating a DOM document from it.
*
* @param string $html
*
* @return string the unified HTML
*/
private function prepareHtmlForDomConversion($html)
{
$htmlWithDocumentType = $this->ensureDocumentType($html);
return $this->addContentTypeMetaTag($htmlWithDocumentType);
}
/**
* Applies $this->css to $this->domDocument.
*
* This method places the CSS inline.
*
* @return void
*
* @throws SyntaxErrorException
*/
protected function process()
{
$this->clearAllCaches();
$this->purgeVisitedNodes();
$xPath = new \DOMXPath($this->domDocument);
$this->removeUnprocessableTags();
$this->normalizeStyleAttributesOfAllNodes($xPath);
// 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);
}
$excludedNodes = $this->getNodesToExclude($xPath);
$cssRules = $this->parseCssRules($allCss);
foreach ($cssRules['inlineable'] as $cssRule) {
try {
$nodesMatchingCssSelectors = $xPath->query($this->cssSelectorConverter->toXPath($cssRule['selector']));
} catch (SyntaxErrorException $e) {
if ($this->debug) {
throw $e;
}
continue;
}
/** @var \DOMElement $node */
foreach ($nodesMatchingCssSelectors as $node) {
if (\in_array($node, $excludedNodes, true)) {
continue;
}
$this->copyInlineableCssToStyleAttribute($node, $cssRule);
}
}
if ($this->isInlineStyleAttributesParsingEnabled) {
$this->fillStyleAttributesWithMergedStyles();
}
$this->postProcess($xPath);
$this->removeImportantAnnotationFromAllInlineStyles($xPath);
$this->copyUninlineableCssToStyleNode($xPath, $cssRules['uninlineable']);
}
/**
* Applies some optional post-processing to the HTML in the DOM document.
*
* @param \DOMXPath $xPath
*
* @return void
*/
private function postProcess(\DOMXPath $xPath)
{
if ($this->shouldRemoveInvisibleNodes) {
$this->removeInvisibleNodes($xPath);
}
}
/**
* Searches for all nodes with a style attribute and removes the "!important" annotations out of
* the inline style declarations, eventually by rearranging declarations.
*
* @param \DOMXPath $xPath
*
* @return void
*/
private function removeImportantAnnotationFromAllInlineStyles(\DOMXPath $xPath)
{
foreach ($this->getAllNodesWithStyleAttribute($xPath) as $node) {
$this->removeImportantAnnotationFromNodeInlineStyle($node);
}
}
/**
* Removes the "!important" annotations out of the inline style declarations,
* eventually by rearranging declarations.
* Rearranging needed when !important shorthand properties are followed by some of their
* not !important expanded-version properties.
* For example "font: 12px serif !important; font-size: 13px;" must be reordered
* to "font-size: 13px; font: 12px serif;" in order to remain correct.
*
* @param \DOMElement $node
*
* @return void
*/
private function removeImportantAnnotationFromNodeInlineStyle(\DOMElement $node)
{
$inlineStyleDeclarations = $this->parseCssDeclarationsBlock($node->getAttribute('style'));
$regularStyleDeclarations = [];
$importantStyleDeclarations = [];
foreach ($inlineStyleDeclarations as $property => $value) {
if ($this->attributeValueIsImportant($value)) {
$importantStyleDeclarations[$property] = \trim(\str_replace('!important', '', $value));
} else {
$regularStyleDeclarations[$property] = $value;
}
}
$inlineStyleDeclarationsInNewOrder = \array_merge(
$regularStyleDeclarations,
$importantStyleDeclarations
);
$node->setAttribute(
'style',
$this->generateStyleStringFromSingleDeclarationsArray($inlineStyleDeclarationsInNewOrder)
);
}
/**
* Returns a list with all DOM nodes that have a style attribute.
*
* @param \DOMXPath $xPath
*
* @return \DOMNodeList
*/
private function getAllNodesWithStyleAttribute(\DOMXPath $xPath)
{
return $xPath->query('//*[@style]');
}
/**
* Extracts and parses the individual rules from a CSS string.
*
* @param string $css a string of raw CSS code
*
* @return string[][][] A 2-entry array with the key "inlineable" containing rules which can be inlined as `style`
* attributes and the key "uninlineable" containing rules which cannot. Each value is an array of string
* sub-arrays with the keys
* "media" (the media query string, e.g. "@media screen and (max-width: 480px)",
* or an empty string if not from a `@media` rule),
* "selector" (the CSS selector, e.g., "*" or "header h1"),
* "hasUnmatchablePseudo" (true if that selector contains psuedo-elements or dynamic pseudo-classes
* such that the declarations cannot be applied inline),
* "declarationsBlock" (the semicolon-separated CSS declarations for that selector,
* e.g., "color: red; height: 4px;"),
* and "line" (the line number e.g. 42)
*/
private function parseCssRules($css)
{
$cssKey = \md5($css);
if (!isset($this->caches[static::CACHE_KEY_CSS][$cssKey])) {
$matches = $this->getCssRuleMatches($css);
$cssRules = [
'inlineable' => [],
'uninlineable' => [],
];
/** @var string[][] $matches */
/** @var string[] $cssRule */
foreach ($matches as $key => $cssRule) {
$cssDeclaration = \trim($cssRule['declarations']);
if ($cssDeclaration === '') {
continue;
}
$selectors = \explode(',', $cssRule['selectors']);
foreach ($selectors as $selector) {
// don't process pseudo-elements and behavioral (dynamic) pseudo-classes;
// only allow structural pseudo-classes
$hasPseudoElement = \strpos($selector, '::') !== false;
$hasUnsupportedPseudoClass = (bool)\preg_match(
'/:(?!' . static::PSEUDO_CLASS_MATCHER . ')[\\w\\-]/i',
$selector
);
$hasUnmatchablePseudo = $hasPseudoElement || $hasUnsupportedPseudoClass;
$parsedCssRule = [
'media' => $cssRule['media'],
'selector' => \trim($selector),
'hasUnmatchablePseudo' => $hasUnmatchablePseudo,
'declarationsBlock' => $cssDeclaration,
// keep track of where it appears in the file, since order is important
'line' => $key,
];
$ruleType = ($cssRule['media'] === '' && !$hasUnmatchablePseudo) ? 'inlineable' : 'uninlineable';
$cssRules[$ruleType][] = $parsedCssRule;
}
}
\usort($cssRules['inlineable'], [$this, 'sortBySelectorPrecedence']);
$this->caches[static::CACHE_KEY_CSS][$cssKey] = $cssRules;
}
return $this->caches[static::CACHE_KEY_CSS][$cssKey];
}
/**
* Parses a string of CSS into the media query, selectors and declarations for each ruleset in order.
*
* @param string $css
*
* @return string[][] Array of string sub-arrays with the keys
* "media" (the media query string, e.g. "@media screen and (max-width: 480px)",
* or an empty string if not from an `@media` rule),
* "selectors" (the CSS selector(s), e.g., "*" or "h1, h2"),
* "declarations" (the semicolon-separated CSS declarations for that/those selector(s),
* e.g., "color: red; height: 4px;"),
*/
private function getCssRuleMatches($css)
{
$ruleMatches = [];
$splitCss = $this->splitCssAndMediaQuery($css);
foreach ($splitCss as $cssPart) {
// process each part for selectors and definitions
\preg_match_all('/(?:^|[\\s^{}]*)([^{]+){([^}]*)}/mi', $cssPart['css'], $matches, PREG_SET_ORDER);
/** @var string[][] $matches */
foreach ($matches as $cssRule) {
$ruleMatches[] = [
'media' => $cssPart['media'],
'selectors' => $cssRule[1],
'declarations' => $cssRule[2],
];
}
}
return $ruleMatches;
}
/**
* 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.
*
* @deprecated will be removed in Emogrifier 3.0
*
* @return void
*/
public function disableInvisibleNodeRemoval()
{
$this->shouldRemoveInvisibleNodes = false;
}
/**
* Clears all caches.
*
* @return void
*/
private function clearAllCaches()
{
$this->caches = [
static::CACHE_KEY_CSS => [],
static::CACHE_KEY_SELECTOR => [],
static::CACHE_KEY_CSS_DECLARATIONS_BLOCK => [],
static::CACHE_KEY_COMBINED_STYLES => [],
];
}
/**
* Purges the visited nodes.
*
* @return void
*/
private function purgeVisitedNodes()
{
$this->visitedNodes = [];
$this->styleAttributesForNodes = [];
}
/**
* 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([$node->parentNode, 'removeChild'])) {
$node->parentNode->removeChild($node);
}
}
}
/**
* Parses the document and normalizes 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 stores a reference of nodes with existing inline styles so we don't overwrite them.
*
* @param \DOMXPath $xPath
*
* @return void
*/
private function normalizeStyleAttributesOfAllNodes(\DOMXPath $xPath)
{
/** @var \DOMElement $node */
foreach ($this->getAllNodesWithStyleAttribute($xPath) as $node) {
if ($this->isInlineStyleAttributesParsingEnabled) {
$this->normalizeStyleAttributes($node);
}
// Remove style attribute in every case, so we can add them back (if inline style attributes
// parsing is enabled) to the end of the style list, thus keeping the right priority of CSS rules;
// else original inline style rules may remain at the beginning of the final inline style definition
// of a node, which may give not the desired results
$node->removeAttribute('style');
}
}
/**
* 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',
function (array $m) {
return \strtolower($m[0]);
},
$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)
{
$cacheKey = \serialize([$oldStyles, $newStyles]);
if (isset($this->caches[static::CACHE_KEY_COMBINED_STYLES][$cacheKey])) {
return $this->caches[static::CACHE_KEY_COMBINED_STYLES][$cacheKey];
}
// Unset the overridden styles to preserve order, important if shorthand and individual properties are mixed
foreach ($oldStyles as $attributeName => $attributeValue) {
if (!isset($newStyles[$attributeName])) {
continue;
}
$newAttributeValue = $newStyles[$attributeName];
if ($this->attributeValueIsImportant($attributeValue)
&& !$this->attributeValueIsImportant($newAttributeValue)
) {
unset($newStyles[$attributeName]);
} else {
unset($oldStyles[$attributeName]);
}
}
$combinedStyles = \array_merge($oldStyles, $newStyles);
$style = '';
foreach ($combinedStyles as $attributeName => $attributeValue) {
$style .= \strtolower(\trim($attributeName)) . ': ' . \trim($attributeValue) . '; ';
}
$trimmedStyle = \rtrim($style);
$this->caches[static::CACHE_KEY_COMBINED_STYLES][$cacheKey] = $trimmedStyle;
return $trimmedStyle;
}
/**
* Generates a CSS style string suitable to be used inline from the $styleDeclarations property => value array.
*
* @param string[] $styleDeclarations
*
* @return string
*/
private function generateStyleStringFromSingleDeclarationsArray(array $styleDeclarations)
{
return $this->generateStyleStringFromDeclarationsArrays([], $styleDeclarations);
}
/**
* Checks whether $attributeValue is marked as !important.
*
* @param string $attributeValue
*
* @return bool
*/
private function attributeValueIsImportant($attributeValue)
{
return \strtolower(\substr(\trim($attributeValue), -10)) === '!important';
}
/**
* Applies $cssRules to $this->domDocument, limited to the rules that actually apply to the document.
*
* @param \DOMXPath $xPath
* @param string[][] $cssRules The "uninlineable" array of CSS rules returned by `parseCssRules`
*
* @return void
*/
private function copyUninlineableCssToStyleNode(\DOMXPath $xPath, array $cssRules)
{
$cssRulesRelevantForDocument = \array_filter(
$cssRules,
function (array $cssRule) use ($xPath) {
$selector = $cssRule['selector'];
if ($cssRule['hasUnmatchablePseudo']) {
$selector = $this->removeUnmatchablePseudoComponents($selector);
}
return $this->existsMatchForCssSelector($xPath, $selector);
}
);
if ($cssRulesRelevantForDocument === []) {
// avoid adding empty style element (or including unneeded class dependency)
return;
}
$cssConcatenator = new CssConcatenator();
foreach ($cssRulesRelevantForDocument as $cssRule) {
$cssConcatenator->append([$cssRule['selector']], $cssRule['declarationsBlock'], $cssRule['media']);
}
$this->addStyleElementToDocument($cssConcatenator->getCss());
}
/**
* Removes pseudo-elements and dynamic pseudo-classes from a CSS selector, replacing them with "*" if necessary.
*
* @param string $selector
*
* @return string Selector which will match the relevant DOM elements if the pseudo-classes are assumed to apply,
* or in the case of pseudo-elements will match their originating element.
*/
private function removeUnmatchablePseudoComponents($selector)
{
$pseudoComponentMatcher = ':(?!' . static::PSEUDO_CLASS_MATCHER . '):?+[\\w\\-]++(?:\\([^\\)]*+\\))?+';
return \preg_replace(
['/(\\s|^)' . $pseudoComponentMatcher . '/i', '/' . $pseudoComponentMatcher . '/i'],
['$1*', ''],
$selector
);
}
/**
* Copies $cssRule into the style attribute of $node.
*
* Note: This method does not check whether $cssRule matches $node.
*
* @param \DOMElement $node
* @param string[][] $cssRule
*
* @return void
*/
private function copyInlineableCssToStyleAttribute(\DOMElement $node, array $cssRule)
{
// if it has a style attribute, get it, process it, and append (overwrite) new stuff
if ($node->hasAttribute('style')) {
// break it up into an associative array
$oldStyleDeclarations = $this->parseCssDeclarationsBlock($node->getAttribute('style'));
} else {
$oldStyleDeclarations = [];
}
$newStyleDeclarations = $this->parseCssDeclarationsBlock($cssRule['declarationsBlock']);
$node->setAttribute(
'style',
$this->generateStyleStringFromDeclarationsArrays($oldStyleDeclarations, $newStyleDeclarations)
);
}
/**
* Checks whether there is at least one matching element for $cssSelector.
* When not in debug mode, it returns true also for invalid selectors (because they may be valid,
* just not implemented/recognized yet by Emogrifier).
*
* @param \DOMXPath $xPath
* @param string $cssSelector
*
* @return bool
*
* @throws SyntaxErrorException
*/
private function existsMatchForCssSelector(\DOMXPath $xPath, $cssSelector)
{
try {
$nodesMatchingSelector = $xPath->query($this->cssSelectorConverter->toXPath($cssSelector));
} catch (SyntaxErrorException $e) {
if ($this->debug) {
throw $e;
}
return true;
}
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 $this->domDocument.
*
* This method is protected to allow overriding.
*
* @see https://github.com/jjriv/emogrifier/issues/103
*
* @param string $css
*
* @return void
*/
protected function addStyleElementToDocument($css)
{
$styleElement = $this->domDocument->createElement('style', $css);
$styleAttribute = $this->domDocument->createAttribute('type');
$styleAttribute->value = 'text/css';
$styleElement->appendChild($styleAttribute);
$headElement = $this->getHeadElement();
$headElement->appendChild($styleElement);
}
/**
* Checks that $this->domDocument has a BODY element and adds it if it is missing.
*
* @return void
*/
private function ensureExistenceOfBodyElement()
{
if ($this->domDocument->getElementsByTagName('body')->item(0) !== null) {
return;
}
$htmlElement = $this->domDocument->getElementsByTagName('html')->item(0);
$htmlElement->appendChild($this->domDocument->createElement('body'));
}
/**
* Splits input CSS code into an array of parts for different media querues, in order.
* Each part is an array where:
*
* - key "css" will contain clean CSS code (for @media rules this will be the group rule body within "{...}")
* - key "media" will contain "@media " followed by the media query list, for all allowed media queries,
* or an empty string for CSS not within a media query
*
* Example:
*
* The CSS code
*
* "@import "file.css"; h1 { color:red; } @media { h1 {}} @media tv { h1 {}}"
*
* will be parsed into the following array:
*
* 0 => [
* "css" => "h1 { color:red; }",
* "media" => ""
* ],
* 1 => [
* "css" => " h1 {}",
* "media" => "@media "
* ]
*
* @param string $css
*
* @return string[][]
*/
private function splitCssAndMediaQuery($css)
{
$cssWithoutComments = \preg_replace('/\\/\\*.*\\*\\//sU', '', $css);
$mediaTypesExpression = '';
if (!empty($this->allowedMediaTypes)) {
$mediaTypesExpression = '|' . \implode('|', \array_keys($this->allowedMediaTypes));
}
$mediaRuleBodyMatcher = '[^{]*+{(?:[^{}]*+{.*})?\\s*+}\\s*+';
$cssSplitForAllowedMediaTypes = \preg_split(
'#(@media\\s++(?:only\\s++)?+(?:(?=[{\\(])' . $mediaTypesExpression . ')' . $mediaRuleBodyMatcher
. ')#misU',
$cssWithoutComments,
-1,
PREG_SPLIT_DELIM_CAPTURE
);
// filter the CSS outside/between allowed @media rules
$cssCleaningMatchers = [
'import/charset directives' => '/\\s*+@(?:import|charset)\\s[^;]++;/i',
'remaining media enclosures' => '/\\s*+@media\\s' . $mediaRuleBodyMatcher . '/isU',
];
$splitCss = [];
foreach ($cssSplitForAllowedMediaTypes as $index => $cssPart) {
$isMediaRule = $index % 2 !== 0;
if ($isMediaRule) {
\preg_match('/^([^{]*+){(.*)}[^}]*+$/s', $cssPart, $matches);
$splitCss[] = [
'css' => $matches[2],
'media' => $matches[1],
];
} else {
$cleanedCss = \trim(\preg_replace($cssCleaningMatchers, '', $cssPart));
if ($cleanedCss !== '') {
$splitCss[] = [
'css' => $cleanedCss,
'media' => '',
];
}
}
}
return $splitCss;
}
/**
* Removes empty unprocessable tags from the DOM document.
*
* @return void
*/
private function removeUnprocessableTags()
{
foreach ($this->unprocessableHtmlTags as $tagName) {
$nodes = $this->domDocument->getElementsByTagName($tagName);
/** @var \DOMNode $node */
foreach ($nodes as $node) {
$hasContent = $node->hasChildNodes() || $node->hasChildNodes();
if (!$hasContent) {
$node->parentNode->removeChild($node);
}
}
}
}
/**
* 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 static::DEFAULT_DOCUMENT_TYPE . $html;
}
/**
* Adds a Content-Type meta tag for the charset.
*
* This method also ensures that there is a HEAD element.
*
* @param string $html
*
* @return string the HTML with the meta tag added
*/
private function addContentTypeMetaTag($html)
{
$hasContentTypeMetaTag = \stripos($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>' . static::CONTENT_TYPE_META_TAG, $html);
} elseif ($hasHtmlTag) {
$reworkedHtml = \preg_replace(
'/<html(.*?)>/i',
'<html$1><head>' . static::CONTENT_TYPE_META_TAG . '</head>',
$html
);
} else {
$reworkedHtml = static::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($this->caches[static::CACHE_KEY_SELECTOR][$selectorKey])) {
$precedence = 0;
foreach ($this->selectorPrecedenceMatchers as $matcher => $value) {
if (\trim($selector) === '') {
break;
}
$number = 0;
$selector = \preg_replace('/' . $matcher . '\\w+/', '', $selector, -1, $number);
$precedence += ($value * $number);
}
$this->caches[static::CACHE_KEY_SELECTOR][$selectorKey] = $precedence;
}
return $this->caches[static::CACHE_KEY_SELECTOR][$selectorKey];
}
/**
* 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($this->caches[static::CACHE_KEY_CSS_DECLARATIONS_BLOCK][$cssDeclarationsBlock])) {
return $this->caches[static::CACHE_KEY_CSS_DECLARATIONS_BLOCK][$cssDeclarationsBlock];
}
$properties = [];
$declarations = \preg_split('/;(?!base64|charset)/', $cssDeclarationsBlock);
foreach ($declarations as $declaration) {
$matches = [];
if (!\preg_match('/^([A-Za-z\\-]+)\\s*:\\s*(.+)$/s', \trim($declaration), $matches)) {
continue;
}
$propertyName = \strtolower($matches[1]);
$propertyValue = $matches[2];
$properties[$propertyName] = $propertyValue;
}
$this->caches[static::CACHE_KEY_CSS_DECLARATIONS_BLOCK][$cssDeclarationsBlock] = $properties;
return $properties;
}
/**
* Find the nodes that are not to be emogrified.
*
* @param \DOMXPath $xPath
*
* @return \DOMElement[]
*
* @throws SyntaxErrorException
*/
private function getNodesToExclude(\DOMXPath $xPath)
{
$excludedNodes = [];
foreach (\array_keys($this->excludedSelectors) as $selectorToExclude) {
try {
$matchingNodes = $xPath->query($this->cssSelectorConverter->toXPath($selectorToExclude));
} catch (SyntaxErrorException $e) {
if ($this->debug) {
throw $e;
}
continue;
}
foreach ($matchingNodes as $node) {
$excludedNodes[] = $node;
}
}
return $excludedNodes;
}
/**
* Sets the debug mode.
*
* @param bool $debug set to true to enable debug mode
*
* @return void
*/
public function setDebug($debug)
{
$this->debug = $debug;
}
}