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         $usesvg = true;
  45     }
  46
  47     list($themename, $rev, $type) = explode('/', $slashargument, 3);
  48     $themename = min_clean_param($themename, 'SAFEDIR');
  49     $rev       = min_clean_param($rev, 'RAW');
  50     $type      = min_clean_param($type, 'SAFEDIR');
  51
  52 } else {
  53     $themename = min_optional_param('theme', 'standard', 'SAFEDIR');
  54     $rev       = min_optional_param('rev', 0, 'RAW');
  55     $type      = min_optional_param('type', 'all', 'SAFEDIR');
  56     $usesvg    = (bool)min_optional_param('svg', '1', 'INT');
  57 }
  58
  59 // Check if we received a theme sub revision which allows us
  60 // to handle local caching on a per theme basis.
  61 $values = explode('_', $rev);
  62 $rev = min_clean_param(array_shift($values), 'INT');
  63 $themesubrev = array_shift($values);
  64
  65 if (!is_null($themesubrev)) {
  66     $themesubrev = min_clean_param($themesubrev, 'INT');
  67 }
  68
  69 // Note: We only check validity of the revision number here, we do not check the theme sub-revision because this is
  70 // not solely based on time.
  71 if (!min_is_revision_valid_and_current($rev)) {
  72     // If the rev is invalid, normalise it to -1 to disable all caching.
  73     $rev = -1;
  74 }
  75
  76 // Check that type fits into the expected values.
  77 if (!in_array($type, ['all', 'all-rtl', 'editor', 'editor-rtl'])) {
  78     css_send_css_not_found();
  79 }
  80
  81 if (file_exists("$CFG->dirroot/theme/$themename/config.php")) {
  82     // The theme exists in standard location - ok.
  83 } else if (!empty($CFG->themedir) and file_exists("$CFG->themedir/$themename/config.php")) {
  84     // Alternative theme location contains this theme - ok.
  85 } else {
  86     header('HTTP/1.0 404 not found');
  87     die('Theme was not found, sorry.');
  88 }
  89
  90 $candidatedir = "$CFG->localcachedir/theme/$rev/$themename/css";
  91 $candidatesheet = "{$candidatedir}/" . theme_styles_get_filename($type, $themesubrev, $usesvg);
  92 $etag = theme_styles_get_etag($themename, $rev, $type, $themesubrev, $usesvg);
  93
  94 if (file_exists($candidatesheet)) {
  95     if (!empty($_SERVER['HTTP_IF_NONE_MATCH']) || !empty($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
  96         // We do not actually need to verify the etag value because our files
  97         // never change in cache because we increment the rev counter.
  98         css_send_unmodified(filemtime($candidatesheet), $etag);
  99     }
 100     css_send_cached_css($candidatesheet, $etag);
 101 }
 102
 103 // Ok, now we need to start normal moodle script, we need to load all libs and $DB.
 104 define('ABORT_AFTER_CONFIG_CANCEL', true);
 105
 106 define('NO_MOODLE_COOKIES', true); // Session not used here.
 107 define('NO_UPGRADE_CHECK', true);  // Ignore upgrade check.
 108
 109 require("$CFG->dirroot/lib/setup.php");
 110
 111 $theme = theme_config::load($themename);
 112 $theme->force_svg_use($usesvg);
 113 $theme->set_rtl_mode(substr($type, -4) === '-rtl');
 114
 115 $themerev = theme_get_revision();
 116 $currentthemesubrev = theme_get_sub_revision_for_theme($themename);
 117
 118 $cache = true;
 119 // If the client is requesting a revision that doesn't match both
 120 // the global theme revision and the theme specific revision then
 121 // tell the browser not to cache this style sheet because it's
 122 // likely being regenerated.
 123 if ($themerev <= 0 or $themerev != $rev or $themesubrev != $currentthemesubrev) {
 124     $rev = $themerev;
 125     $themesubrev = $currentthemesubrev;
 126     $cache = false;
 127
 128     $candidatedir = "$CFG->localcachedir/theme/$rev/$themename/css";
 129     $candidatesheet = "{$candidatedir}/" . theme_styles_get_filename($type, $themesubrev, $usesvg);
 130     $etag = theme_styles_get_etag($themename, $rev, $type, $themesubrev, $usesvg);
 131 }
 132
 133 make_localcache_directory('theme', false);
 134
 135 if ($type === 'editor' || $type === 'editor-rtl') {
 136     $csscontent = $theme->get_css_content_editor();
 137
 138     if ($cache) {
 139         css_store_css($theme, $candidatesheet, $csscontent);
 140         css_send_cached_css($candidatesheet, $etag);
 141     } else {
 142         css_send_uncached_css($csscontent);
 143     }
 144
 145 }
 146
 147 if (($fallbacksheet = theme_styles_fallback_content($theme)) && !$theme->has_css_cached_content()) {
 148     // The theme is not yet available and a fallback is available.
 149     // Return the fallback immediately, specifying the Content-Length, then generate in the background.
 150     $css = file_get_contents($fallbacksheet);
 151     css_send_temporary_css($css);
 152
 153     // The fallback content has now been sent.
 154     // There will be an attempt to generate the content, but it should not be served.
 155     // The Content-Length above means that the client will disregard it anyway.
 156     $sendaftergeneration = false;
 157
 158     // There may be another client currently holding a lock and generating the stylesheet.
 159     // Use a very low lock timeout as the connection will be ended immediately afterwards.
 160     $locktimeout = 1;
 161 } else {
 162     // There is no fallback content to be issued here, therefore the generated content must be output.
 163     $sendaftergeneration = true;
 164
 165     // Use a realistic lock timeout as the intention is to avoid lock contention.
 166     $locktimeout = rand(90, 120);
 167 }
 168
 169 // Attempt to fetch the lock.
 170 $lockfactory = \core\lock\lock_config::get_lock_factory('core_theme_get_css_content');
 171 $lock = $lockfactory->get_lock($themename, $locktimeout);
 172
 173 if ($sendaftergeneration || $lock) {
 174     // Either the lock was successful, or the lock was unsuccessful but the content *must* be sent.
 175
 176     // The content does not exist locally.
 177     // Generate and save it.
 178     $candidatesheet = theme_styles_generate_and_store($theme, $rev, $themesubrev, $candidatedir);
 179
 180     if ($lock) {
 181         $lock->release();
 182     }
 183
 184     if ($sendaftergeneration) {
 185         if (!$cache) {
 186             // Do not pollute browser caches if invalid revision requested,
 187             // let's ignore legacy IE breakage here too.
 188             css_send_uncached_css(file_get_contents($candidatesheet));
 189
 190         } else {
 191             // Real browsers - this is the expected result!
 192             css_send_cached_css($candidatesheet, $etag);
 193         }
 194     }
 195 }
 196
 197 /**
 198  * Generate the theme CSS and store it.
 199  *
 200  * @param   theme_config    $theme The theme to be generated
 201  * @param   int             $rev The theme revision
 202  * @param   int             $themesubrev The theme sub-revision
 203  * @param   string          $candidatedir The directory that it should be stored in
 204  * @return  string          The path that the primary CSS was written to
 205  */
 206 function theme_styles_generate_and_store($theme, $rev, $themesubrev, $candidatedir) {
 207     global $CFG;
 208     require_once("{$CFG->libdir}/filelib.php");
 209
 210     // Generate the content first.
 211     if (!$csscontent = $theme->get_css_cached_content()) {
 212         $csscontent = $theme->get_css_content();
 213         $theme->set_css_content_cache($csscontent);
 214     }
 215
 216     if ($theme->get_rtl_mode()) {
 217         $type = "all-rtl";
 218     } else {
 219         $type = "all";
 220     }
 221
 222     // Determine the candidatesheet path.
 223     $candidatesheet = "{$candidatedir}/" . theme_styles_get_filename($type, $themesubrev, $theme->use_svg_icons());
 224
 225     // Store the CSS.
 226     css_store_css($theme, $candidatesheet, $csscontent);
 227
 228     // Store the fallback CSS in the temp directory.
 229     // This file is used as a fallback when waiting for a theme to compile and is not versioned in any way.
 230     $fallbacksheet = make_temp_directory("theme/{$theme->name}")
 231         . "/"
 232         . theme_styles_get_filename($type, 0, $theme->use_svg_icons());
 233     css_store_css($theme, $fallbacksheet, $csscontent);
 234
 235     // Delete older revisions from localcache.
 236     $themecachedirs = glob("{$CFG->localcachedir}/theme/*", GLOB_ONLYDIR);
 237     foreach ($themecachedirs as $localcachedir) {
 238         $cachedrev = [];
 239         preg_match("/\/theme\/([0-9]+)$/", $localcachedir, $cachedrev);
 240         $cachedrev = isset($cachedrev[1]) ? intval($cachedrev[1]) : 0;
 241         if ($cachedrev > 0 && $cachedrev < $rev) {
 242             fulldelete($localcachedir);
 243         }
 244     }
 245
 246     // Delete older theme subrevision CSS from localcache.
 247     $subrevfiles = glob("{$CFG->localcachedir}/theme/{$rev}/{$theme->name}/css/*.css");
 248     foreach ($subrevfiles as $subrevfile) {
 249         $cachedsubrev = [];
 250         preg_match("/_([0-9]+)\.([0-9]+\.)?css$/", $subrevfile, $cachedsubrev);
 251         $cachedsubrev = isset($cachedsubrev[1]) ? intval($cachedsubrev[1]) : 0;
 252         if ($cachedsubrev > 0 && $cachedsubrev < $themesubrev) {
 253             fulldelete($subrevfile);
 254         }
 255     }
 256
 257     return $candidatesheet;
 258 }
 259
 260 /**
 261  * Fetch the preferred fallback content location if available.
 262  *
 263  * @param   theme_config    $theme The theme to be generated
 264  * @return  string          The path to the fallback sheet on disk
 265  */
 266 function theme_styles_fallback_content($theme) {
 267     global $CFG;
 268
 269     if (!$theme->usefallback) {
 270         // This theme does not support fallbacks.
 271         return false;
 272     }
 273
 274     $type = $theme->get_rtl_mode() ? 'all-rtl' : 'all';
 275     $filename = theme_styles_get_filename($type);
 276
 277     $fallbacksheet = "{$CFG->tempdir}/theme/{$theme->name}/{$filename}";
 278     if (file_exists($fallbacksheet)) {
 279         return $fallbacksheet;
 280     }
 281
 282     return false;
 283 }
 284
 285 /**
 286  * Get the filename for the specified configuration.
 287  *
 288  * @param   string  $type The requested sheet type
 289  * @param   int     $themesubrev The theme sub-revision
 290  * @param   bool    $usesvg Whether SVGs are allowed
 291  * @return  string  The filename for this sheet
 292  */
 293 function theme_styles_get_filename($type, $themesubrev = 0, $usesvg = true) {
 294     $filename = $type;
 295     $filename .= ($themesubrev > 0) ? "_{$themesubrev}" : '';
 296     $filename .= $usesvg ? '' : '-nosvg';
 297
 298     return "{$filename}.css";
 299 }
 300
 301 /**
 302  * Determine the correct etag for the specified configuration.
 303  *
 304  * @param   string  $themename The name of the theme
 305  * @param   int     $rev The revision number
 306  * @param   string  $type The requested sheet type
 307  * @param   int     $themesubrev The theme sub-revision
 308  * @param   bool    $usesvg Whether SVGs are allowed
 309  * @return  string  The etag to use for this request
 310  */
 311 function theme_styles_get_etag($themename, $rev, $type, $themesubrev, $usesvg) {
 312     $etag = [$rev, $themename, $type, $themesubrev];
 313
 314     if (!$usesvg) {
 315         $etag[] = 'nosvg';
 316     }
 317
 318     return sha1(implode('/', $etag));
 319 }