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