theme/styles.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 /**
  18  * This file is responsible for serving the one huge CSS of each theme.
  19  *
  20  * @package   core
  21  * @copyright 2009 Petr Skoda (skodak)  {@link http://skodak.org}
  22  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23  */
  24
  25 // Disable moodle specific debug messages and any errors in output,
  26 // comment out when debugging or better look into error log!
  27 define('NO_DEBUG_DISPLAY', true);
  28
  29 define('ABORT_AFTER_CONFIG', true);
  30 require('../config.php');
  31 require_once($CFG->dirroot.'/lib/csslib.php');
  32
  33 if ($slashargument = min_get_slash_argument()) {
  34     $slashargument = ltrim($slashargument, '/');
  35     if (substr_count($slashargument, '/') < 2) {
  36         css_send_css_not_found();
  37     }
  38
  39     if (strpos($slashargument, '_s/') === 0) {
  40         // Can't use SVG.
  41         $slashargument = substr($slashargument, 3);
  42         $usesvg = false;
  43     } else {
  44         $usesvg = true;
  45     }
  46
  47     $chunk = null;
  48     if (preg_match('#/(chunk(\d+)(/|$))#', $slashargument, $matches)) {
  49         $chunk = (int)$matches[2];
  50         $slashargument = str_replace($matches[1], '', $slashargument);
  51     }
  52
  53     list($themename, $rev, $type) = explode('/', $slashargument, 3);
  54     $themename = min_clean_param($themename, 'SAFEDIR');
  55     $rev       = min_clean_param($rev, 'RAW');
  56     $type      = min_clean_param($type, 'SAFEDIR');
  57
  58 } else {
  59     $themename = min_optional_param('theme', 'standard', 'SAFEDIR');
  60     $rev       = min_optional_param('rev', 0, 'RAW');
  61     $type      = min_optional_param('type', 'all', 'SAFEDIR');
  62     $chunk     = min_optional_param('chunk', null, 'INT');
  63     $usesvg    = (bool)min_optional_param('svg', '1', 'INT');
  64 }
  65
  66 // Check if we received a theme sub revision which allows us
  67 // to handle local caching on a per theme basis.
  68 $values = explode('_', $rev);
  69 $rev = min_clean_param(array_shift($values), 'INT');
  70 $themesubrev = array_shift($values);
  71
  72 if (is_null($themesubrev)) {
  73     // Default to the current theme subrevision if one isn't
  74     // provided in the URL.
  75     $themesubrev = theme_get_sub_revision_for_theme($themename);
  76 } else {
  77     $themesubrev = min_clean_param($themesubrev, 'INT');
  78 }
  79
  80 // Check that type fits into the expected values.
  81 if ($type === 'editor') {
  82     // The editor CSS is never chunked.
  83     $chunk = null;
  84 } else if ($type === 'all' || $type === 'all-rtl') {
  85     // We're fine.
  86 } else {
  87     css_send_css_not_found();
  88 }
  89
  90 if (file_exists("$CFG->dirroot/theme/$themename/config.php")) {
  91     // The theme exists in standard location - ok.
  92 } else if (!empty($CFG->themedir) and file_exists("$CFG->themedir/$themename/config.php")) {
  93     // Alternative theme location contains this theme - ok.
  94 } else {
  95     header('HTTP/1.0 404 not found');
  96     die('Theme was not found, sorry.');
  97 }
  98
  99 $candidatedir = "$CFG->localcachedir/theme/$rev/$themename/css";
 100 $candidatesheet = "{$candidatedir}/" . theme_styles_get_filename($type, $themesubrev, $usesvg);
 101 $chunkedcandidatesheet = "{$candidatedir}/" . theme_styles_get_filename($type, $themesubrev, $usesvg, $chunk);
 102 $etag = theme_styles_get_etag($themename, $rev, $type, $themesubrev, $usesvg, $chunk);
 103
 104 if (file_exists($chunkedcandidatesheet)) {
 105     if (!empty($_SERVER['HTTP_IF_NONE_MATCH']) || !empty($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
 106         // We do not actually need to verify the etag value because our files
 107         // never change in cache because we increment the rev counter.
 108         css_send_unmodified(filemtime($chunkedcandidatesheet), $etag);
 109     }
 110     css_send_cached_css($chunkedcandidatesheet, $etag);
 111 }
 112
 113 // Ok, now we need to start normal moodle script, we need to load all libs and $DB.
 114 define('ABORT_AFTER_CONFIG_CANCEL', true);
 115
 116 define('NO_MOODLE_COOKIES', true); // Session not used here.
 117 define('NO_UPGRADE_CHECK', true);  // Ignore upgrade check.
 118
 119 require("$CFG->dirroot/lib/setup.php");
 120
 121 $theme = theme_config::load($themename);
 122 $theme->force_svg_use($usesvg);
 123 $theme->set_rtl_mode($type === 'all-rtl' ? true : false);
 124
 125 $themerev = theme_get_revision();
 126 $currentthemesubrev = theme_get_sub_revision_for_theme($themename);
 127
 128 $cache = true;
 129 // If the client is requesting a revision that doesn't match both
 130 // the global theme revision and the theme specific revision then
 131 // tell the browser not to cache this style sheet because it's
 132 // likely being regenerated.
 133 if ($themerev <= 0 or $themerev != $rev or $themesubrev != $currentthemesubrev) {
 134     $rev = $themerev;
 135     $cache = false;
 136
 137     $candidatedir = "$CFG->localcachedir/theme/$rev/$themename/css";
 138     $candidatesheet = "{$candidatedir}/" . theme_styles_get_filename($type, $themesubrev, $usesvg);
 139     $chunkedcandidatesheet = "{$candidatedir}/" . theme_styles_get_filename($type, $themesubrev, $usesvg, $chunk);
 140     $etag = theme_styles_get_etag($themename, $rev, $type, $themesubrev, $usesvg, $chunk);
 141 }
 142
 143 make_localcache_directory('theme', false);
 144
 145 if ($type === 'editor') {
 146     $csscontent = $theme->get_css_content_editor();
 147     css_store_css($theme, $candidatesheet, $csscontent, false);
 148
 149     if ($cache) {
 150         css_send_cached_css($candidatesheet, $etag);
 151     } else {
 152         css_send_uncached_css(file_get_contents($candidatesheet));
 153     }
 154
 155 }
 156
 157 if (($fallbacksheet = theme_styles_fallback_content($theme)) && !$theme->has_css_cached_content()) {
 158     // The theme is not yet available and a fallback is available.
 159     // Return the fallback immediately, specifying the Content-Length, then generate in the background.
 160     $css = file_get_contents($fallbacksheet);
 161     css_send_temporary_css($css);
 162
 163     // The fallback content has now been sent.
 164     // There will be an attempt to generate the content, but it should not be served.
 165     // The Content-Length above means that the client will disregard it anyway.
 166     $sendaftergeneration = false;
 167
 168     // There may be another client currently holding a lock and generating the stylesheet.
 169     // Use a very low lock timeout as the connection will be ended immediately afterwards.
 170     $locktimeout = 1;
 171 } else {
 172     // There is no fallback content to be issued here, therefore the generated content must be output.
 173     $sendaftergeneration = true;
 174
 175     // Use a realistic lock timeout as the intention is to avoid lock contention.
 176     $locktimeout = rand(90, 120);
 177 }
 178
 179 // Attempt to fetch the lock.
 180 $lockfactory = \core\lock\lock_config::get_lock_factory('core_theme_get_css_content');
 181 $lock = $lockfactory->get_lock($themename, $locktimeout);
 182
 183 if ($sendaftergeneration || $lock) {
 184     // Either the lock was successful, or the lock was unsuccessful but the content *must* be sent.
 185     if (!file_exists($chunkedcandidatesheet)) {
 186         // The content does not exist locally.
 187         // Generate and save it.
 188         $candidatesheet = theme_styles_generate_and_store($theme, $rev, $themesubrev, $candidatedir);
 189     }
 190
 191     if ($lock) {
 192         $lock->release();
 193     }
 194
 195     if ($sendaftergeneration) {
 196         if (!$cache) {
 197             // Do not pollute browser caches if invalid revision requested,
 198             // let's ignore legacy IE breakage here too.
 199             css_send_uncached_css(file_get_contents($candidatesheet));
 200
 201         } else if ($chunk !== null and file_exists($chunkedcandidatesheet)) {
 202             // Greetings stupid legacy IEs!
 203             css_send_cached_css($chunkedcandidatesheet, $etag);
 204
 205         } else {
 206             // Real browsers - this is the expected result!
 207             css_send_cached_css($candidatesheet, $etag);
 208         }
 209     }
 210 }
 211
 212 /**
 213  * Generate the theme CSS and store it.
 214  *
 215  * @param   theme_config    $theme The theme to be generated
 216  * @param   int             $rev The theme revision
 217  * @param   int             $themesubrev The theme sub-revision
 218  * @param   string          $candidatedir The directory that it should be stored in
 219  * @return  string          The path that the primary (non-chunked) CSS was written to
 220  */
 221 function theme_styles_generate_and_store($theme, $rev, $themesubrev, $candidatedir) {
 222     global $CFG;
 223
 224     // Generate the content first.
 225     if (!$csscontent = $theme->get_css_cached_content()) {
 226         $csscontent = $theme->get_css_content();
 227         $theme->set_css_content_cache($csscontent);
 228     }
 229
 230     if ($theme->get_rtl_mode()) {
 231         $type = "all-rtl";
 232     } else {
 233         $type = "all";
 234     }
 235
 236     // Determine the candidatesheet path.
 237     // Note: Do not pass any value for chunking as this is calcualted during css storage.
 238     $candidatesheet = "{$candidatedir}/" . theme_styles_get_filename($type, $themesubrev, $theme->use_svg_icons());
 239
 240     // Determine the chunking URL.
 241     // Note, this will be removed when support for IE9 is removed.
 242     $relroot = preg_replace('|^http.?://[^/]+|', '', $CFG->wwwroot);
 243     if (!empty(min_get_slash_argument())) {
 244         if ($theme->use_svg_icons()) {
 245             $chunkurl = "{$relroot}/theme/styles.php/{$theme->name}/{$rev}/$type";
 246         } else {
 247             $chunkurl = "{$relroot}/theme/styles.php/_s/{$theme->name}/{$rev}/$type";
 248         }
 249     } else {
 250         if ($theme->use_svg_icons()) {
 251             $chunkurl = "{$relroot}/theme/styles.php?theme={$theme->name}&rev={$rev}&type=$type";
 252         } else {
 253             $chunkurl = "{$relroot}/theme/styles.php?theme={$theme->name}&rev={$rev}&type=$type&svg=0";
 254         }
 255     }
 256
 257     // Store the CSS.
 258     css_store_css($theme, $candidatesheet, $csscontent, true, $chunkurl);
 259
 260     // Store the fallback CSS in the temp directory.
 261     // This file is used as a fallback when waiting for a theme to compile and is not versioned in any way.
 262     $fallbacksheet = make_temp_directory("theme/{$theme->name}")
 263         . "/"
 264         . theme_styles_get_filename($type, 0, $theme->use_svg_icons());
 265     css_store_css($theme, $fallbacksheet, $csscontent, true, $chunkurl);
 266
 267     return $candidatesheet;
 268 }
 269
 270 /**
 271  * Fetch the preferred fallback content location if available.
 272  *
 273  * @param   theme_config    $theme The theme to be generated
 274  * @return  string          The path to the fallback sheet on disk
 275  */
 276 function theme_styles_fallback_content($theme) {
 277     global $CFG;
 278
 279     if (!$theme->usefallback) {
 280         // This theme does not support fallbacks.
 281         return false;
 282     }
 283
 284     $type = $theme->get_rtl_mode() ? 'all-rtl' : 'all';
 285     $filename = theme_styles_get_filename($type);
 286
 287     $fallbacksheet = "{$CFG->tempdir}/theme/{$theme->name}/{$filename}";
 288     if (file_exists($fallbacksheet)) {
 289         return $fallbacksheet;
 290     }
 291
 292     return false;
 293 }
 294
 295 /**
 296  * Get the filename for the specified configuration.
 297  *
 298  * @param   string  $type The requested sheet type
 299  * @param   int     $themesubrev The theme sub-revision
 300  * @param   bool    $usesvg Whether SVGs are allowed
 301  * @param   int     $chunk The chunk number if specified
 302  * @return  string  The filename for this sheet
 303  */
 304 function theme_styles_get_filename($type, $themesubrev = 0, $usesvg = true, $chunk = null) {
 305     $filename = $type;
 306     $filename .= ($themesubrev > 0) ? "_{$themesubrev}" : '';
 307     $filename .= $usesvg ? '' : '-nosvg';
 308     $filename .= $chunk ? ".{$chunk}" : '';
 309
 310     return "{$filename}.css";
 311 }
 312
 313 /**
 314  * Determine the correct etag for the specified configuration.
 315  *
 316  * @param   string  $themename The name of the theme
 317  * @param   int     $rev The revision number
 318  * @param   string  $type The requested sheet type
 319  * @param   int     $themesubrev The theme sub-revision
 320  * @param   bool    $usesvg Whether SVGs are allowed
 321  * @param   int     $chunk The chunk number if specified
 322  * @return  string  The etag to use for this request
 323  */
 324 function theme_styles_get_etag($themename, $rev, $type, $themesubrev, $usesvg, $chunk) {
 325     $etag = [$rev, $themename, $type, $themesubrev];
 326
 327     if (!$usesvg) {
 328         $etag[] = 'nosvg';
 329     }
 330
 331     if ($chunk) {
 332         $etag[] = "chunk{$chunk}";
 333     }
 334
 335     return sha1(implode('/', $etag));
 336 }