3 * Minification of CSS stylesheets.
5 * Copyright 2010 Wikimedia Foundation
7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
8 * not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software distributed
14 * under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS
15 * OF ANY KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations under the License.
19 * @version 0.1.1 -- 2010-09-11
20 * @author Trevor Parscal <tparscal@wikimedia.org>
21 * @copyright Copyright 2010 Wikimedia Foundation
22 * @license http://www.apache.org/licenses/LICENSE-2.0
28 * This class provides minification, URL remapping, URL extracting, and data-URL embedding.
34 /** @var string Strip marker for comments. **/
35 const PLACEHOLDER
= "\x7fPLACEHOLDER\x7f";
38 * Internet Explorer data URI length limit. See encodeImageAsDataURI().
40 const DATA_URI_SIZE_LIMIT
= 32768;
41 const URL_REGEX
= 'url\(\s*[\'"]?(?P<file>[^\?\)\'"]*?)(?P<query>\?[^\)\'"]*?|)[\'"]?\s*\)';
42 const EMBED_REGEX
= '\/\*\s*\@embed\s*\*\/';
43 const COMMENT_REGEX
= '\/\*.*?\*\/';
45 /* Protected Static Members */
47 /** @var array List of common image files extensions and MIME-types */
48 protected static $mimeTypes = array(
50 'jpe' => 'image/jpeg',
51 'jpeg' => 'image/jpeg',
52 'jpg' => 'image/jpeg',
54 'tif' => 'image/tiff',
55 'tiff' => 'image/tiff',
56 'xbm' => 'image/x-xbitmap',
57 'svg' => 'image/svg+xml',
63 * Gets a list of local file paths which are referenced in a CSS style sheet.
65 * If you wish non-existent files to be listed too, use getAllLocalFileReferences().
67 * For backwards-compatibility, if the second parameter is not given or null,
68 * this function will return an empty array instead of erroring out.
70 * @param string $source CSS stylesheet source to process
71 * @param string $path File path where the source was read from
72 * @return array List of local file references
74 public static function getLocalFileReferences( $source, $path = null ) {
75 if ( $path === null ) {
79 $files = self
::getAllLocalFileReferences( $source, $path );
81 // Skip non-existent files
82 $files = array_filter( $files, function ( $file ) {
83 return file_exists( $file );
90 * Gets a list of local file paths which are referenced in a CSS style sheet, including
93 * @param string $source CSS stylesheet source to process
94 * @param string $path File path where the source wa
95 * @return array List of local file references
97 public static function getAllLocalFileReferences( $source, $path ) {
98 $path = rtrim( $path, '/' ) . '/';
101 $rFlags = PREG_OFFSET_CAPTURE | PREG_SET_ORDER
;
102 if ( preg_match_all( '/' . self
::URL_REGEX
. '/', $source, $matches, $rFlags ) ) {
103 foreach ( $matches as $match ) {
104 $url = $match['file'][0];
106 // Skip fully-qualified and protocol-relative URLs and data URIs
107 if ( substr( $url, 0, 2 ) === '//' ||
parse_url( $url, PHP_URL_SCHEME
) ) {
111 $files[] = $path . $url;
118 * Encode an image file as a data URI.
120 * If the image file has a suitable MIME type and size, encode it as a data URI, base64-encoded
121 * for binary files or just percent-encoded otherwise. Return false if the image type is
122 * unfamiliar or file exceeds the size limit.
124 * @param string $file Image file to encode.
125 * @param string|null $type File's MIME type or null. If null, CSSMin will
126 * try to autodetect the type.
127 * @param bool $ie8Compat By default, a data URI will only be produced if it can be made short
128 * enough to fit in Internet Explorer 8 (and earlier) URI length limit (32,768 bytes). Pass
129 * `false` to remove this limitation.
130 * @return string|bool Image contents encoded as a data URI or false.
132 public static function encodeImageAsDataURI( $file, $type = null, $ie8Compat = true ) {
133 // Fast-fail for files that definitely exceed the maximum data URI length
134 if ( $ie8Compat && filesize( $file ) >= self
::DATA_URI_SIZE_LIMIT
) {
138 if ( $type === null ) {
139 $type = self
::getMimeType( $file );
145 return self
::encodeStringAsDataURI( file_get_contents( $file ), $type, $ie8Compat );
149 * Encode file contents as a data URI with chosen MIME type.
151 * The URI will be base64-encoded for binary files or just percent-encoded otherwise.
155 * @param string $contents File contents to encode.
156 * @param string $type File's MIME type.
157 * @param bool $ie8Compat See encodeImageAsDataURI().
158 * @return string|bool Image contents encoded as a data URI or false.
160 public static function encodeStringAsDataURI( $contents, $type, $ie8Compat = true ) {
161 // Try #1: Non-encoded data URI
162 // The regular expression matches ASCII whitespace and printable characters.
163 if ( preg_match( '/^[\r\n\t\x20-\x7e]+$/', $contents ) ) {
164 // Do not base64-encode non-binary files (sane SVGs).
165 // (This often produces longer URLs, but they compress better, yielding a net smaller size.)
166 $uri = 'data:' . $type . ',' . rawurlencode( $contents );
167 if ( !$ie8Compat ||
strlen( $uri ) < self
::DATA_URI_SIZE_LIMIT
) {
172 // Try #2: Encoded data URI
173 $uri = 'data:' . $type . ';base64,' . base64_encode( $contents );
174 if ( !$ie8Compat ||
strlen( $uri ) < self
::DATA_URI_SIZE_LIMIT
) {
178 // A data URI couldn't be produced
183 * @param $file string
184 * @return bool|string
186 public static function getMimeType( $file ) {
187 $realpath = realpath( $file );
190 && function_exists( 'finfo_file' )
191 && function_exists( 'finfo_open' )
192 && defined( 'FILEINFO_MIME_TYPE' )
194 return finfo_file( finfo_open( FILEINFO_MIME_TYPE
), $realpath );
197 // Infer the MIME-type from the file extension
198 $ext = strtolower( pathinfo( $file, PATHINFO_EXTENSION
) );
199 if ( isset( self
::$mimeTypes[$ext] ) ) {
200 return self
::$mimeTypes[$ext];
207 * Build a CSS 'url()' value for the given URL, quoting parentheses (and other funny characters)
208 * and escaping quotes as necessary.
210 * See http://www.w3.org/TR/css-syntax-3/#consume-a-url-token
212 * @param string $url URL to process
213 * @return string 'url()' value, usually just `"url($url)"`, quoted/escaped if necessary
215 public static function buildUrlValue( $url ) {
216 // The list below has been crafted to match URLs such as:
217 // scheme://user@domain:port/~user/fi%20le.png?query=yes&really=y+s
218 // data:image/png;base64,R0lGODlh/+==
219 if ( preg_match( '!^[\w\d:@/~.%+;,?&=-]+$!', $url ) ) {
222 return 'url("' . strtr( $url, array( '\\' => '\\\\', '"' => '\\"' ) ) . '")';
227 * Remaps CSS URL paths and automatically embeds data URIs for CSS rules
228 * or url() values preceded by an / * @embed * / comment.
230 * @param string $source CSS data to remap
231 * @param string $local File path where the source was read from
232 * @param string $remote URL path to the file
233 * @param bool $embedData If false, never do any data URI embedding,
234 * even if / * @embed * / is found.
235 * @return string Remapped CSS data
237 public static function remap( $source, $local, $remote, $embedData = true ) {
238 // High-level overview:
239 // * For each CSS rule in $source that includes at least one url() value:
240 // * Check for an @embed comment at the start indicating that all URIs should be embedded
241 // * For each url() value:
242 // * Check for an @embed comment directly preceding the value
243 // * If either @embed comment exists:
244 // * Embedding the URL as data: URI, if it's possible / allowed
245 // * Otherwise remap the URL to work in generated stylesheets
247 // Guard against trailing slashes, because "some/remote/../foo.png"
248 // resolves to "some/remote/foo.png" on (some?) clients (bug 27052).
249 if ( substr( $remote, -1 ) == '/' ) {
250 $remote = substr( $remote, 0, -1 );
253 // Disallow U+007F DELETE, which is illegal anyway, and which
254 // we use for comment placeholders.
255 $source = str_replace( "\x7f", "?", $source );
257 // Replace all comments by a placeholder so they will not interfere with the remapping.
258 // Warning: This will also catch on anything looking like the start of a comment between
259 // quotation marks (e.g. "foo /* bar").
262 $pattern = '/(?!' . CSSMin
::EMBED_REGEX
. ')(' . CSSMin
::COMMENT_REGEX
. ')/s';
264 $source = preg_replace_callback(
266 function ( $match ) use ( &$comments ) {
267 $comments[] = $match[ 0 ];
268 return CSSMin
::PLACEHOLDER
. ( count( $comments ) - 1 ) . 'x';
273 // Note: This will not correctly handle cases where ';', '{' or '}'
274 // appears in the rule itself, e.g. in a quoted string. You are advised
275 // not to use such characters in file names. We also match start/end of
276 // the string to be consistent in edge-cases ('@import url(…)').
277 $pattern = '/(?:^|[;{])\K[^;{}]*' . CSSMin
::URL_REGEX
. '[^;}]*(?=[;}]|$)/';
279 $source = preg_replace_callback(
281 function ( $matchOuter ) use ( $local, $remote, $embedData ) {
282 $rule = $matchOuter[0];
284 // Check for global @embed comment and remove it. Allow other comments to be present
285 // before @embed (they have been replaced with placeholders at this point).
287 $rule = preg_replace( '/^((?:\s+|' . CSSMin
::PLACEHOLDER
. '(\d+)x)*)' . CSSMin
::EMBED_REGEX
. '\s*/', '$1', $rule, 1, $embedAll );
289 // Build two versions of current rule: with remapped URLs
290 // and with embedded data: URIs (where possible).
291 $pattern = '/(?P<embed>' . CSSMin
::EMBED_REGEX
. '\s*|)' . CSSMin
::URL_REGEX
. '/';
293 $ruleWithRemapped = preg_replace_callback(
295 function ( $match ) use ( $local, $remote ) {
296 $remapped = CSSMin
::remapOne( $match['file'], $match['query'], $local, $remote, false );
298 return CSSMin
::buildUrlValue( $remapped );
304 // Remember the occurring MIME types to avoid fallbacks when embedding some files.
305 $mimeTypes = array();
307 $ruleWithEmbedded = preg_replace_callback(
309 function ( $match ) use ( $embedAll, $local, $remote, &$mimeTypes ) {
310 $embed = $embedAll ||
$match['embed'];
311 $embedded = CSSMin
::remapOne(
319 $url = $match['file'] . $match['query'];
320 $file = $local . $match['file'];
322 !CSSMin
::isRemoteUrl( $url ) && !CSSMin
::isLocalUrl( $url )
323 && file_exists( $file )
325 $mimeTypes[ CSSMin
::getMimeType( $file ) ] = true;
328 return CSSMin
::buildUrlValue( $embedded );
333 // Are all referenced images SVGs?
334 $needsEmbedFallback = $mimeTypes !== array( 'image/svg+xml' => true );
337 if ( !$embedData ||
$ruleWithEmbedded === $ruleWithRemapped ) {
338 // We're not embedding anything, or we tried to but the file is not embeddable
339 return $ruleWithRemapped;
340 } elseif ( $embedData && $needsEmbedFallback ) {
341 // Build 2 CSS properties; one which uses a data URI in place of the @embed comment, and
342 // the other with a remapped and versioned URL with an Internet Explorer 6 and 7 hack
343 // making it ignored in all browsers that support data URIs
344 return "$ruleWithEmbedded;$ruleWithRemapped!ie";
346 // Look ma, no fallbacks! This is for files which IE 6 and 7 don't support anyway: SVG.
347 return $ruleWithEmbedded;
351 // Re-insert comments
352 $pattern = '/' . CSSMin
::PLACEHOLDER
. '(\d+)x/';
353 $source = preg_replace_callback( $pattern, function( $match ) use ( &$comments ) {
354 return $comments[ $match[1] ];
362 * Is this CSS rule referencing a remote URL?
364 * @private Until we require PHP 5.5 and we can access self:: from closures.
365 * @param string $maybeUrl
368 public static function isRemoteUrl( $maybeUrl ) {
369 if ( substr( $maybeUrl, 0, 2 ) === '//' ||
parse_url( $maybeUrl, PHP_URL_SCHEME
) ) {
376 * Is this CSS rule referencing a local URL?
378 * @private Until we require PHP 5.5 and we can access self:: from closures.
379 * @param string $maybeUrl
382 public static function isLocalUrl( $maybeUrl ) {
383 if ( $maybeUrl !== '' && $maybeUrl[0] === '/' && !self
::isRemoteUrl( $maybeUrl ) ) {
390 * Remap or embed a CSS URL path.
392 * @param string $file URL to remap/embed
393 * @param string $query
394 * @param string $local File path where the source was read from
395 * @param string $remote URL path to the file
396 * @param bool $embed Whether to do any data URI embedding
397 * @return string Remapped/embedded URL data
399 public static function remapOne( $file, $query, $local, $remote, $embed ) {
400 // The full URL possibly with query, as passed to the 'url()' value in CSS
401 $url = $file . $query;
403 // Expand local URLs with absolute paths like /w/index.php to possibly protocol-relative URL, if
404 // wfExpandUrl() is available. (This will not be the case if we're running outside of MW.)
405 if ( self
::isLocalUrl( $url ) && function_exists( 'wfExpandUrl' ) ) {
406 return wfExpandUrl( $url, PROTO_RELATIVE
);
409 // Pass thru fully-qualified and protocol-relative URLs and data URIs, as well as local URLs if
410 // we can't expand them.
411 if ( self
::isRemoteUrl( $url ) || self
::isLocalUrl( $url ) ) {
415 if ( $local === false ) {
416 // Assume that all paths are relative to $remote, and make them absolute
417 $url = $remote . '/' . $url;
419 // We drop the query part here and instead make the path relative to $remote
420 $url = "{$remote}/{$file}";
421 // Path to the actual file on the filesystem
422 $localFile = "{$local}/{$file}";
423 if ( file_exists( $localFile ) ) {
424 // Add version parameter as the first five hex digits
425 // of the MD5 hash of the file's contents.
426 $url .= '?' . substr( md5_file( $localFile ), 0, 5 );
428 $data = self
::encodeImageAsDataURI( $localFile );
429 if ( $data !== false ) {
434 // If any of these conditions failed (file missing, we don't want to embed it
435 // or it's not embeddable), return the URL (possibly with ?timestamp part)
437 if ( function_exists( 'wfRemoveDotSegments' ) ) {
438 $url = wfRemoveDotSegments( $url );
444 * Removes whitespace from CSS data
446 * @param string $css CSS data to minify
447 * @return string Minified CSS data
449 public static function minify( $css ) {
452 array( '; ', ': ', ' {', '{ ', ', ', '} ', ';}' ),
453 array( ';', ':', '{', '{', ',', '}', '}' ),
454 preg_replace( array( '/\s+/', '/\/\*.*?\*\//s' ), array( ' ', '' ), $css )