<?php
declare(strict_types=1);
namespace Pelago\Emogrifier;
use Pelago\Emogrifier\Css\CssDocument;
use Pelago\Emogrifier\HtmlProcessor\AbstractHtmlProcessor;
use Pelago\Emogrifier\Utilities\CssConcatenator;
use Symfony\Component\CssSelector\CssSelectorConverter;
use Symfony\Component\CssSelector\Exception\ParseException;
/**
* This class provides functions for converting CSS styles into inline style attributes in your HTML code.
*/
class CssInliner extends AbstractHtmlProcessor
{
/**
* @var int
*/
private const CACHE_KEY_SELECTOR = 0;
/**
* @var int
*/
private const CACHE_KEY_CSS_DECLARATIONS_BLOCK = 1;
/**
* @var int
*/
private const CACHE_KEY_COMBINED_STYLES = 2;
/**
* 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
*/
private const PSEUDO_CLASS_MATCHER
= 'empty|(?:first|last|nth(?:-last)?+|only)-(?:child|of-type)|not\\([[:ascii:]]*\\)';
/**
* This regular expression componenet matches an `...of-type` pseudo class name, without the preceding ":". These
* pseudo-classes can currently online be inlined if they have an associated type in the selector expression.
*
* @var string
*/
private const OF_TYPE_PSEUDO_CLASS_MATCHER = '(?:first|last|nth(?:-last)?+|only)-of-type';
/**
* regular expression component to match a selector combinator
*
* @var string
*/
private const COMBINATOR_MATCHER = '(?:\\s++|\\s*+[>+~]\\s*+)(?=[[:alpha:]_\\-.#*:\\[])';
/**
* @var array<string, bool>
*/
private $excludedSelectors = [];
/**
* @var array<string, bool>
*/
private $allowedMediaTypes = ['all' => true, 'screen' => true, 'print' => true];
/**
* @var array{
* 0: array<string, int>,
* 1: array<string, array<string, string>>,
* 2: array<string, string>
* }
*/
private $caches = [
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 array<string, \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 array<string, array<string, 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;
/**
* 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 array<string, 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,
];
/**
* array of data describing CSS rules which apply to the document but cannot be inlined, in the format returned by
* {@see collateCssRules}
*
* @var array<array-key, array{
* media: string,
* selector: string,
* hasUnmatchablePseudo: bool,
* declarationsBlock: string,
* line: int
* }>|null
*/
private $matchingUninlinableCssRules = null;
/**
* Emogrifier will throw Exceptions when it encounters an error instead of silently ignoring them.
*
* @var bool
*/
private $debug = false;
/**
* Inlines the given CSS into the existing HTML.
*
* @param string $css the CSS to inline, must be UTF-8-encoded
*
* @return self fluent interface
*
* @throws ParseException in debug mode, if an invalid selector is encountered
* @throws \RuntimeException in debug mode, if an internal PCRE error occurs
*/
public function inlineCss(string $css = ''): self
{
$this->clearAllCaches();
$this->purgeVisitedNodes();
$this->normalizeStyleAttributesOfAllNodes();
$combinedCss = $css;
// grab any existing style blocks from the HTML and append them to the existing CSS
// (these blocks should be appended so as to have precedence over conflicting styles in the existing CSS)
if ($this->isStyleBlocksParsingEnabled) {
$combinedCss .= $this->getCssFromAllStyleNodes();
}
$parsedCss = new CssDocument($combinedCss);
$excludedNodes = $this->getNodesToExclude();
$cssRules = $this->collateCssRules($parsedCss);
$cssSelectorConverter = $this->getCssSelectorConverter();
foreach ($cssRules['inlinable'] as $cssRule) {
try {
$nodesMatchingCssSelectors = $this->getXPath()
->query($cssSelectorConverter->toXPath($cssRule['selector']));
/** @var \DOMElement $node */
foreach ($nodesMatchingCssSelectors as $node) {
if (\in_array($node, $excludedNodes, true)) {
continue;
}
$this->copyInlinableCssToStyleAttribute($node, $cssRule);
}
} catch (ParseException $e) {
if ($this->debug) {
throw $e;
}
}
}
if ($this->isInlineStyleAttributesParsingEnabled) {
$this->fillStyleAttributesWithMergedStyles();
}
$this->removeImportantAnnotationFromAllInlineStyles();
$this->determineMatchingUninlinableCssRules($cssRules['uninlinable']);
$this->copyUninlinableCssToStyleNode($parsedCss);
return $this;
}
/**
* Disables the parsing of inline styles.
*
* @return self fluent interface
*/
public function disableInlineStyleAttributesParsing(): self
{
$this->isInlineStyleAttributesParsingEnabled = false;
return $this;
}
/**
* Disables the parsing of `<style>` blocks.
*
* @return self fluent interface
*/
public function disableStyleBlocksParsing(): self
{
$this->isStyleBlocksParsingEnabled = false;
return $this;
}
/**
* Marks a media query type to keep.
*
* @param string $mediaName the media type name, e.g., "braille"
*
* @return self fluent interface
*/
public function addAllowedMediaType(string $mediaName): self
{
$this->allowedMediaTypes[$mediaName] = true;
return $this;
}
/**
* Drops a media query type from the allowed list.
*
* @param string $mediaName the tag name, e.g., "braille"
*
* @return self fluent interface
*/
public function removeAllowedMediaType(string $mediaName): self
{
if (isset($this->allowedMediaTypes[$mediaName])) {
unset($this->allowedMediaTypes[$mediaName]);
}
return $this;
}
/**
* 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 self fluent interface
*/
public function addExcludedSelector(string $selector): self
{
$this->excludedSelectors[$selector] = true;
return $this;
}
/**
* No longer excludes the nodes matching this selector from emogrification.
*
* @param string $selector the selector to no longer exclude, e.g., ".editor"
*
* @return self fluent interface
*/
public function removeExcludedSelector(string $selector): self
{
if (isset($this->excludedSelectors[$selector])) {
unset($this->excludedSelectors[$selector]);
}
return $this;
}
/**
* Sets the debug mode.
*
* @param bool $debug set to true to enable debug mode
*
* @return self fluent interface
*/
public function setDebug(bool $debug): self
{
$this->debug = $debug;
return $this;
}
/**
* Gets the array of selectors present in the CSS provided to `inlineCss()` for which the declarations could not be
* applied as inline styles, but which may affect elements in the HTML. The relevant CSS will have been placed in a
* `<style>` element. The selectors may include those used within `@media` rules or those involving dynamic
* pseudo-classes (such as `:hover`) or pseudo-elements (such as `::after`).
*
* @return array<array-key, string>
*
* @throws \BadMethodCallException if `inlineCss` has not been called first
*/
public function getMatchingUninlinableSelectors(): array
{
return \array_column($this->getMatchingUninlinableCssRules(), 'selector');
}
/**
* @return array<array-key, array{
* media: string,
* selector: string,
* hasUnmatchablePseudo: bool,
* declarationsBlock: string,
* line: int
* }>
*
* @throws \BadMethodCallException if `inlineCss` has not been called first
*/
private function getMatchingUninlinableCssRules(): array
{
if (!\is_array($this->matchingUninlinableCssRules)) {
throw new \BadMethodCallException('inlineCss must be called first', 1568385221);
}
return $this->matchingUninlinableCssRules;
}
/**
* Clears all caches.
*/
private function clearAllCaches(): void
{
$this->caches = [
self::CACHE_KEY_SELECTOR => [],
self::CACHE_KEY_CSS_DECLARATIONS_BLOCK => [],
self::CACHE_KEY_COMBINED_STYLES => [],
];
}
/**
* Purges the visited nodes.
*/
private function purgeVisitedNodes(): void
{
$this->visitedNodes = [];
$this->styleAttributesForNodes = [];
}
/**
* 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.
*/
private function normalizeStyleAttributesOfAllNodes(): void
{
/** @var \DOMElement $node */
foreach ($this->getAllNodesWithStyleAttribute() 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');
}
}
/**
* Returns a list with all DOM nodes that have a style attribute.
*
* @return \DOMNodeList
*
* @throws \RuntimeException
*/
private function getAllNodesWithStyleAttribute(): \DOMNodeList
{
$query = '//*[@style]';
$matches = $this->getXPath()->query($query);
if (!$matches instanceof \DOMNodeList) {
throw new \RuntimeException('XPatch query failed: ' . $query, 1618577797);
}
return $matches;
}
/**
* Normalizes the value of the "style" attribute and saves it.
*
* @param \DOMElement $node
*/
private function normalizeStyleAttributes(\DOMElement $node): void
{
$normalizedOriginalStyle = \preg_replace_callback(
'/-?+[_a-zA-Z][\\w\\-]*+(?=:)/S',
/** @param array<array-key, string> $propertyNameMatches */
static function (array $propertyNameMatches): string {
return \strtolower($propertyNameMatches[0]);
},
$node->getAttribute('style')
);
// In order to not overwrite existing style attributes in the HTML, we have to save the original HTML styles.
$nodePath = $node->getNodePath();
if (\is_string($nodePath) && !isset($this->styleAttributesForNodes[$nodePath])) {
$this->styleAttributesForNodes[$nodePath] = $this->parseCssDeclarationsBlock($normalizedOriginalStyle);
$this->visitedNodes[$nodePath] = $node;
}
$node->setAttribute('style', $normalizedOriginalStyle);
}
/**
* 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 array<string, string>
* the CSS declarations with the property names as array keys and the property values as array values
*/
private function parseCssDeclarationsBlock(string $cssDeclarationsBlock): array
{
if (isset($this->caches[self::CACHE_KEY_CSS_DECLARATIONS_BLOCK][$cssDeclarationsBlock])) {
return $this->caches[self::CACHE_KEY_CSS_DECLARATIONS_BLOCK][$cssDeclarationsBlock];
}
$properties = [];
foreach (\preg_split('/;(?!base64|charset)/', $cssDeclarationsBlock) as $declaration) {
/** @var array<int, string> $matches */
$matches = [];
if (!\preg_match('/^([A-Za-z\\-]+)\\s*:\\s*(.+)$/s', \trim($declaration), $matches)) {
continue;
}
$propertyName = \strtolower($matches[1]);
$propertyValue = $matches[2];
$properties[$propertyName] = $propertyValue;
}
$this->caches[self::CACHE_KEY_CSS_DECLARATIONS_BLOCK][$cssDeclarationsBlock] = $properties;
return $properties;
}
/**
* Returns CSS content.
*
* @return string
*/
private function getCssFromAllStyleNodes(): string
{
$styleNodes = $this->getXPath()->query('//style');
if ($styleNodes === false) {
return '';
}
$css = '';
foreach ($styleNodes as $styleNode) {
$css .= "\n\n" . $styleNode->nodeValue;
$parentNode = $styleNode->parentNode;
if ($parentNode instanceof \DOMNode) {
$parentNode->removeChild($styleNode);
}
}
return $css;
}
/**
* Find the nodes that are not to be emogrified.
*
* @return array<int, \DOMElement>
*
* @throws ParseException
* @throws \UnexpectedValueException
*/
private function getNodesToExclude(): array
{
$excludedNodes = [];
foreach (\array_keys($this->excludedSelectors) as $selectorToExclude) {
try {
$matchingNodes = $this->getXPath()
->query($this->getCssSelectorConverter()->toXPath($selectorToExclude));
foreach ($matchingNodes as $node) {
if (!$node instanceof \DOMElement) {
$path = $node->getNodePath() ?? '$node';
throw new \UnexpectedValueException($path . ' is not a DOMElement.', 1617975914);
}
$excludedNodes[] = $node;
}
} catch (ParseException $e) {
if ($this->debug) {
throw $e;
}
}
}
return $excludedNodes;
}
/**
* @return CssSelectorConverter
*/
private function getCssSelectorConverter(): CssSelectorConverter
{
if (!$this->cssSelectorConverter instanceof CssSelectorConverter) {
$this->cssSelectorConverter = new CssSelectorConverter();
}
return $this->cssSelectorConverter;
}
/**
* Collates the individual rules from a `CssDocument` object.
*
* @param CssDocument $parsedCss
*
* @return array<string, array<array-key, array{
* media: string,
* selector: string,
* hasUnmatchablePseudo: bool,
* declarationsBlock: string,
* line: int
* }>>
* This 2-entry array has the key "inlinable" containing rules which can be inlined as `style` attributes
* and the key "uninlinable" containing rules which cannot. Each value is an array of sub-arrays with the
* following 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 pseudo-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;`);
* - "line" (the line number, e.g. 42).
*/
private function collateCssRules(CssDocument $parsedCss): array
{
$matches = $parsedCss->getStyleRulesData(\array_keys($this->allowedMediaTypes));
$cssRules = [
'inlinable' => [],
'uninlinable' => [],
];
foreach ($matches as $key => $cssRule) {
if (!$cssRule->hasAtLeastOneDeclaration()) {
continue;
}
$mediaQuery = $cssRule->getContainingAtRule();
$declarationsBlock = $cssRule->getDeclarationAsText();
foreach ($cssRule->getSelectors() as $selector) {
// don't process pseudo-elements and behavioral (dynamic) pseudo-classes;
// only allow structural pseudo-classes
$hasPseudoElement = \strpos($selector, '::') !== false;
$hasUnmatchablePseudo = $hasPseudoElement || $this->hasUnsupportedPseudoClass($selector);
$parsedCssRule = [
'media' => $mediaQuery,
'selector' => $selector,
'hasUnmatchablePseudo' => $hasUnmatchablePseudo,
'declarationsBlock' => $declarationsBlock,
// keep track of where it appears in the file, since order is important
'line' => $key,
];
$ruleType = (!$cssRule->hasContainingAtRule() && !$hasUnmatchablePseudo) ? 'inlinable' : 'uninlinable';
$cssRules[$ruleType][] = $parsedCssRule;
}
}
\usort(
$cssRules['inlinable'],
/**
* @param array{selector: string, line: int} $first
* @param array{selector: string, line: int} $second
*/
function (array $first, array $second): int {
return $this->sortBySelectorPrecedence($first, $second);
}
);
return $cssRules;
}
/**
* Tests if a selector contains a pseudo-class which would mean it cannot be converted to an XPath expression for
* inlining CSS declarations.
*
* Any pseudo class that does not match {@see PSEUDO_CLASS_MATCHER} cannot be converted. Additionally, `...of-type`
* pseudo-classes cannot be converted if they are not associated with a type selector.
*
* @param string $selector
*
* @return bool
*/
private function hasUnsupportedPseudoClass(string $selector): bool
{
if (\preg_match('/:(?!' . self::PSEUDO_CLASS_MATCHER . ')[\\w\\-]/i', $selector)) {
return true;
}
if (!\preg_match('/:(?:' . self::OF_TYPE_PSEUDO_CLASS_MATCHER . ')/i', $selector)) {
return false;
}
foreach (\preg_split('/' . self::COMBINATOR_MATCHER . '/', $selector) as $selectorPart) {
if ($this->selectorPartHasUnsupportedOfTypePseudoClass($selectorPart)) {
return true;
}
}
return false;
}
/**
* Tests if part of a selector contains an `...of-type` pseudo-class such that it cannot be converted to an XPath
* expression.
*
* @param string $selectorPart part of a selector which has been split up at combinators
*
* @return bool `true` if the selector part does not have a type but does have an `...of-type` pseudo-class
*/
private function selectorPartHasUnsupportedOfTypePseudoClass(string $selectorPart): bool
{
if (\preg_match('/^[\\w\\-]/', $selectorPart)) {
return false;
}
return (bool)\preg_match('/:(?:' . self::OF_TYPE_PSEUDO_CLASS_MATCHER . ')/i', $selectorPart);
}
/**
* @param array{selector: string, line: int} $first
* @param array{selector: string, line: int} $second
*
* @return int
*/
private function sortBySelectorPrecedence(array $first, array $second): int
{
$precedenceOfFirst = $this->getCssSelectorPrecedence($first['selector']);
$precedenceOfSecond = $this->getCssSelectorPrecedence($second['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 = $first['line'] < $second['line'] ? -1 : 1;
$precedenceForNotEquals = $precedenceOfFirst < $precedenceOfSecond ? -1 : 1;
return ($precedenceOfFirst === $precedenceOfSecond) ? $precedenceForEquals : $precedenceForNotEquals;
}
/**
* @param string $selector
*
* @return int
*/
private function getCssSelectorPrecedence(string $selector): int
{
$selectorKey = \md5($selector);
if (isset($this->caches[self::CACHE_KEY_SELECTOR][$selectorKey])) {
return $this->caches[self::CACHE_KEY_SELECTOR][$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 * (int)$number);
}
$this->caches[self::CACHE_KEY_SELECTOR][$selectorKey] = $precedence;
return $precedence;
}
/**
* Copies $cssRule into the style attribute of $node.
*
* Note: This method does not check whether $cssRule matches $node.
*
* @param \DOMElement $node
* @param array{
* media: string,
* selector: string,
* hasUnmatchablePseudo: bool,
* declarationsBlock: string,
* line: int
* } $cssRule
*/
private function copyInlinableCssToStyleAttribute(\DOMElement $node, array $cssRule): void
{
$declarationsBlock = $cssRule['declarationsBlock'];
$newStyleDeclarations = $this->parseCssDeclarationsBlock($declarationsBlock);
if ($newStyleDeclarations === []) {
return;
}
// if it has a style attribute, get it, process it, and append (overwrite) new stuff
if ($node->hasAttribute('style')) {
// break it up into an associative array
$oldStyleDeclarations = $this->parseCssDeclarationsBlock($node->getAttribute('style'));
} else {
$oldStyleDeclarations = [];
}
$node->setAttribute(
'style',
$this->generateStyleStringFromDeclarationsArrays($oldStyleDeclarations, $newStyleDeclarations)
);
}
/**
* 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 array<string, string> $oldStyles
* @param array<string, string> $newStyles
*
* @return string
*/
private function generateStyleStringFromDeclarationsArrays(array $oldStyles, array $newStyles): string
{
$cacheKey = \serialize([$oldStyles, $newStyles]);
if (isset($this->caches[self::CACHE_KEY_COMBINED_STYLES][$cacheKey])) {
return $this->caches[self::CACHE_KEY_COMBINED_STYLES][$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);
$this->caches[self::CACHE_KEY_COMBINED_STYLES][$cacheKey] = $trimmedStyle;
return $trimmedStyle;
}
/**
* Checks whether $attributeValue is marked as !important.
*
* @param string $attributeValue
*
* @return bool
*/
private function attributeValueIsImportant(string $attributeValue): bool
{
return (bool)\preg_match('/!\\s*+important$/i', $attributeValue);
}
/**
* Merges styles from styles attributes and style nodes and applies them to the attribute nodes
*/
private function fillStyleAttributesWithMergedStyles(): void
{
foreach ($this->styleAttributesForNodes as $nodePath => $styleAttributesForNode) {
$node = $this->visitedNodes[$nodePath];
$currentStyleAttributes = $this->parseCssDeclarationsBlock($node->getAttribute('style'));
$node->setAttribute(
'style',
$this->generateStyleStringFromDeclarationsArrays(
$currentStyleAttributes,
$styleAttributesForNode
)
);
}
}
/**
* Searches for all nodes with a style attribute and removes the "!important" annotations out of
* the inline style declarations, eventually by rearranging declarations.
*
* @throws \RuntimeException
*/
private function removeImportantAnnotationFromAllInlineStyles(): void
{
/** @var \DOMElement $node */
foreach ($this->getAllNodesWithStyleAttribute() 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
*
* @throws \RuntimeException
*/
private function removeImportantAnnotationFromNodeInlineStyle(\DOMElement $node): void
{
$inlineStyleDeclarations = $this->parseCssDeclarationsBlock($node->getAttribute('style'));
/** @var array<string, string> $regularStyleDeclarations */
$regularStyleDeclarations = [];
/** @var array<string, string> $importantStyleDeclarations */
$importantStyleDeclarations = [];
foreach ($inlineStyleDeclarations as $property => $value) {
if ($this->attributeValueIsImportant($value)) {
$importantStyleDeclarations[$property] = $this->pregReplace('/\\s*+!\\s*+important$/i', '', $value);
} else {
$regularStyleDeclarations[$property] = $value;
}
}
$inlineStyleDeclarationsInNewOrder = \array_merge($regularStyleDeclarations, $importantStyleDeclarations);
$node->setAttribute(
'style',
$this->generateStyleStringFromSingleDeclarationsArray($inlineStyleDeclarationsInNewOrder)
);
}
/**
* Generates a CSS style string suitable to be used inline from the $styleDeclarations property => value array.
*
* @param array<string, string> $styleDeclarations
*
* @return string
*/
private function generateStyleStringFromSingleDeclarationsArray(array $styleDeclarations): string
{
return $this->generateStyleStringFromDeclarationsArrays([], $styleDeclarations);
}
/**
* Determines which of `$cssRules` actually apply to `$this->domDocument`, and sets them in
* `$this->matchingUninlinableCssRules`.
*
* @param array<array-key, array{
* media: string,
* selector: string,
* hasUnmatchablePseudo: bool,
* declarationsBlock: string,
* line: int
* }> $cssRules
* the "uninlinable" array of CSS rules returned by `collateCssRules`
*/
private function determineMatchingUninlinableCssRules(array $cssRules): void
{
$this->matchingUninlinableCssRules = \array_filter(
$cssRules,
function (array $cssRule): bool {
return $this->existsMatchForSelectorInCssRule($cssRule);
}
);
}
/**
* Checks whether there is at least one matching element for the CSS selector contained in the `selector` element
* of the provided CSS rule.
*
* Any dynamic pseudo-classes will be assumed to apply. If the selector matches a pseudo-element,
* it will test for a match with its originating element.
*
* @param array{
* media: string,
* selector: string,
* hasUnmatchablePseudo: bool,
* declarationsBlock: string,
* line: int
* } $cssRule
*
* @return bool
*
* @throws ParseException
*/
private function existsMatchForSelectorInCssRule(array $cssRule): bool
{
$selector = $cssRule['selector'];
if ($cssRule['hasUnmatchablePseudo']) {
$selector = $this->removeUnmatchablePseudoComponents($selector);
}
return $this->existsMatchForCssSelector($selector);
}
/**
* 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 string $cssSelector
*
* @return bool
*
* @throws ParseException
*/
private function existsMatchForCssSelector(string $cssSelector): bool
{
try {
$nodesMatchingSelector = $this->getXPath()->query($this->getCssSelectorConverter()->toXPath($cssSelector));
} catch (ParseException $e) {
if ($this->debug) {
throw $e;
}
return true;
}
return $nodesMatchingSelector !== false && $nodesMatchingSelector->length !== 0;
}
/**
* Removes pseudo-elements and dynamic pseudo-classes from a CSS selector, replacing them with "*" if necessary.
* If such a pseudo-component is within the argument of `:not`, the entire `:not` component is removed or replaced.
*
* @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(string $selector): string
{
// The regex allows nested brackets via `(?2)`.
// A space is temporarily prepended because the callback can't determine if the match was at the very start.
$selectorWithoutNots = \ltrim(\preg_replace_callback(
'/([\\s>+~]?+):not(\\([^()]*+(?:(?2)[^()]*+)*+\\))/i',
/** @param array<array-key, string> $matches */
function (array $matches): string {
return $this->replaceUnmatchableNotComponent($matches);
},
' ' . $selector
));
$selectorWithoutUnmatchablePseudoComponents = $this->removeSelectorComponents(
':(?!' . self::PSEUDO_CLASS_MATCHER . '):?+[\\w\\-]++(?:\\([^\\)]*+\\))?+',
$selectorWithoutNots
);
if (
!\preg_match(
'/:(?:' . self::OF_TYPE_PSEUDO_CLASS_MATCHER . ')/i',
$selectorWithoutUnmatchablePseudoComponents
)
) {
return $selectorWithoutUnmatchablePseudoComponents;
}
return \implode('', \array_map(
function (string $selectorPart): string {
return $this->removeUnsupportedOfTypePseudoClasses($selectorPart);
},
\preg_split(
'/(' . self::COMBINATOR_MATCHER . ')/',
$selectorWithoutUnmatchablePseudoComponents,
-1,
PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY
)
));
}
/**
* Helps `removeUnmatchablePseudoComponents()` replace or remove a selector `:not(...)` component if its argument
* contains pseudo-elements or dynamic pseudo-classes.
*
* @param array<array-key, string> $matches array of elements matched by the regular expression
*
* @return string
* the full match if there were no unmatchable pseudo components within; otherwise, any preceding combinator
* followed by "*", or an empty string if there was no preceding combinator
*/
private function replaceUnmatchableNotComponent(array $matches): string
{
[$notComponentWithAnyPrecedingCombinator, $anyPrecedingCombinator, $notArgumentInBrackets] = $matches;
if ($this->hasUnsupportedPseudoClass($notArgumentInBrackets)) {
return $anyPrecedingCombinator !== '' ? $anyPrecedingCombinator . '*' : '';
}
return $notComponentWithAnyPrecedingCombinator;
}
/**
* Removes components from a CSS selector, replacing them with "*" if necessary.
*
* @param string $matcher regular expression part to match the components to remove
* @param string $selector
*
* @return string
* selector which will match the relevant DOM elements if the removed components are assumed to apply (or in
* the case of pseudo-elements will match their originating element)
*/
private function removeSelectorComponents(string $matcher, string $selector): string
{
return \preg_replace(
['/([\\s>+~]|^)' . $matcher . '/i', '/' . $matcher . '/i'],
['$1*', ''],
$selector
);
}
/**
* Removes any `...-of-type` pseudo-classes from part of a CSS selector, if it does not have a type, replacing them
* with "*" if necessary.
*
* @param string $selectorPart part of a selector which has been split up at combinators
*
* @return string
* selector part which will match the relevant DOM elements if the pseudo-classes are assumed to apply
*/
private function removeUnsupportedOfTypePseudoClasses(string $selectorPart): string
{
if (!$this->selectorPartHasUnsupportedOfTypePseudoClass($selectorPart)) {
return $selectorPart;
}
return $this->removeSelectorComponents(
':(?:' . self::OF_TYPE_PSEUDO_CLASS_MATCHER . ')(?:\\([^\\)]*+\\))?+',
$selectorPart
);
}
/**
* Applies `$this->matchingUninlinableCssRules` to `$this->domDocument` by placing them as CSS in a `<style>`
* element.
* If there are no uninlinable CSS rules to copy there, a `<style>` element will be created containing only the
* applicable at-rules from `$parsedCss`.
* If there are none of either, an empty `<style>` element will not be created.
*
* @param CssDocument $parsedCss
* This may contain various at-rules whose content `CssInliner` does not currently attempt to inline or
* process in any other way, such as `@import`, `@font-face`, `@keyframes`, etc., and which should precede
* the processed but found-to-be-uninlinable CSS placed in the `<style>` element.
* Note that `CssInliner` processes `@media` rules so that they can be ordered correctly with respect to
* other uninlinable rules; these will not be duplicated from `$parsedCss`.
*/
private function copyUninlinableCssToStyleNode(CssDocument $parsedCss): void
{
$css = $parsedCss->renderNonConditionalAtRules();
// avoid including unneeded class dependency if there are no rules
if ($this->getMatchingUninlinableCssRules() !== []) {
$cssConcatenator = new CssConcatenator();
foreach ($this->getMatchingUninlinableCssRules() as $cssRule) {
$cssConcatenator->append([$cssRule['selector']], $cssRule['declarationsBlock'], $cssRule['media']);
}
$css .= $cssConcatenator->getCss();
}
// avoid adding empty style element
if ($css !== '') {
$this->addStyleElementToDocument($css);
}
}
/**
* Adds a style element with $css to $this->domDocument.
*
* This method is protected to allow overriding.
*
* @see https://github.com/MyIntervals/emogrifier/issues/103
*
* @param string $css
*/
protected function addStyleElementToDocument(string $css): void
{
$domDocument = $this->getDomDocument();
$styleElement = $domDocument->createElement('style', $css);
$styleAttribute = $domDocument->createAttribute('type');
$styleAttribute->value = 'text/css';
$styleElement->appendChild($styleAttribute);
$headElement = $this->getHeadElement();
$headElement->appendChild($styleElement);
}
/**
* Returns the HEAD element.
*
* This method assumes that there always is a HEAD element.
*
* @return \DOMElement
*
* @throws \UnexpectedValueException
*/
private function getHeadElement(): \DOMElement
{
$node = $this->getDomDocument()->getElementsByTagName('head')->item(0);
if (!$node instanceof \DOMElement) {
throw new \UnexpectedValueException('There is no HEAD element. This should never happen.', 1617923227);
}
return $node;
}
/**
* Wraps `preg_replace`. If an error occurs (which is highly unlikely), either it is logged and the original
* `$subject` is returned, or in debug mode an exception is thrown.
*
* This method only supports strings, not arrays of strings.
*
* @param string $pattern
* @param string $replacement
* @param string $subject
*
* @return string
*
* @throws \RuntimeException
*/
private function pregReplace(string $pattern, string $replacement, string $subject): string
{
$result = \preg_replace($pattern, $replacement, $subject);
if (!\is_string($result)) {
$this->logOrThrowPregLastError();
$result = $subject;
}
return $result;
}
/**
* Obtains the name of the error constant for `preg_last_error` (based on code posted at
* {@see https://www.php.net/manual/en/function.preg-last-error.php#124124}) and puts it into an error message
* which is either passed to `trigger_error` (in non-debug mode) or an exception which is thrown (in debug mode).
*
* @throws \RuntimeException
*/
private function logOrThrowPregLastError(): void
{
$pcreConstants = \get_defined_constants(true)['pcre'];
$pcreErrorConstantNames = \array_flip(\array_filter(
$pcreConstants,
static function (string $key): bool {
return \substr($key, -6) === '_ERROR';
},
ARRAY_FILTER_USE_KEY
));
$pregLastError = \preg_last_error();
$message = 'PCRE regex execution error `' . (string)($pcreErrorConstantNames[$pregLastError] ?? $pregLastError)
. '`';
if ($this->debug) {
throw new \RuntimeException($message, 1592870147);
}
\trigger_error($message);
}
}