Commit c724390a authored by catch's avatar catch

Issue #2897408 by cburschka, gapple, xjm, effulgentsia: Remove IE9 support...

Issue #2897408 by cburschka, gapple, xjm, effulgentsia: Remove IE9 support from CssCollectionRenderer and provide it in contrib instead
parent 4af96a6a
......@@ -2,54 +2,10 @@
namespace Drupal\Core\Asset;
use Drupal\Component\Utility\Html;
use Drupal\Core\State\StateInterface;
* Renders CSS assets.
* For production websites, LINK tags are preferable to STYLE tags with @import
* statements, because:
* - They are the standard tag intended for linking to a resource.
* - On Firefox 2 and perhaps other browsers, CSS files included with @import
* statements don't get saved when saving the complete web page for offline
* use:
* - On IE, if only LINK tags and no @import statements are used, all the CSS
* files are downloaded in parallel, resulting in faster page load, but if
* @import statements are used and span across multiple STYLE tags, all the
* ones from one STYLE tag must be downloaded before downloading begins for
* the next STYLE tag. Furthermore, IE7 does not support media declaration on
* the @import statement, so multiple STYLE tags must be used when different
* files are for different media types. Non-IE browsers always download in
* parallel, so this is an IE-specific performance quirk:
* However, IE has an annoying limit of 31 total CSS inclusion tags
* ( and LINK tags are limited to one file
* per tag, whereas STYLE tags can contain multiple @import statements allowing
* multiple files to be loaded per tag. When CSS aggregation is disabled, a
* Drupal site can easily have more than 31 CSS files that need to be loaded, so
* using LINK tags exclusively would result in a site that would display
* incorrectly in IE. Depending on different needs, different strategies can be
* employed to decide when to use LINK tags and when to use STYLE tags.
* The strategy employed by this class is to use LINK tags for all aggregate
* files and for all files that cannot be aggregated (e.g., if 'preprocess' is
* set to FALSE or the type is 'external'), and to use STYLE tags for groups
* of files that could be aggregated together but aren't (e.g., if the site-wide
* aggregation setting is disabled). This results in all LINK tags when
* aggregation is enabled, a guarantee that as many or only slightly more tags
* are used with aggregation disabled than enabled (so that if the limit were to
* be crossed with aggregation enabled, the site developer would also notice the
* problem while aggregation is disabled), and an easy way for a developer to
* view HTML source while aggregation is disabled and know what files will be
* aggregated together when aggregation becomes enabled.
* This class evaluates the aggregation enabled/disabled condition on a group
* by group basis by testing whether an aggregate file has been made for the
* group rather than by testing the site-wide aggregation setting. This allows
* this class to work correctly even if modules have implemented custom
* logic for grouping and aggregating files.
class CssCollectionRenderer implements AssetCollectionRendererInterface {
......@@ -90,126 +46,30 @@ public function render(array $css_assets) {
'rel' => 'stylesheet',
$style_element_defaults = [
'#type' => 'html_tag',
'#tag' => 'style',
// For filthy IE hack.
$current_ie_group_keys = NULL;
$get_ie_group_key = function ($css_asset) {
return [$css_asset['type'], $css_asset['preprocess'], $css_asset['group'], $css_asset['media'], $css_asset['browsers']];
foreach ($css_assets as $css_asset) {
$element = $link_element_defaults;
$element['#attributes']['media'] = $css_asset['media'];
$element['#browsers'] = $css_asset['browsers'];
// Loop through all CSS assets, by key, to allow for the special IE
// workaround.
$css_assets_keys = array_keys($css_assets);
for ($i = 0; $i < count($css_assets_keys); $i++) {
$css_asset = $css_assets[$css_assets_keys[$i]];
switch ($css_asset['type']) {
// For file items, there are three possibilities.
// - There are up to 31 CSS assets on the page (some of which may be
// aggregated). In this case, output a LINK tag for file CSS assets.
// - There are more than 31 CSS assets on the page, yet we must stay
// below IE<10's limit of 31 total CSS inclusion tags, we handle this
// in two ways:
// - file CSS assets that are not eligible for aggregation (their
// 'preprocess' flag has been set to FALSE): in this case, output a
// LINK tag.
// - file CSS assets that can be aggregated (and possibly have been):
// in this case, figure out which subsequent file CSS assets share
// the same key properties ('group', 'media' and 'browsers') and
// output this group into as few STYLE tags as possible (a STYLE
// tag may contain only 31 @import statements).
// For file items, output a LINK tag for file CSS assets.
case 'file':
// The dummy query string needs to be added to the URL to control
// browser-caching.
$query_string_separator = (strpos($css_asset['data'], '?') !== FALSE) ? '&' : '?';
// As long as the current page will not run into IE's limit for CSS
// assets: output a LINK tag for a file CSS asset.
if (count($css_assets) <= 31) {
$element = $link_element_defaults;
$element['#attributes']['href'] = file_url_transform_relative(file_create_url($css_asset['data'])) . $query_string_separator . $query_string;
$element['#attributes']['media'] = $css_asset['media'];
$element['#browsers'] = $css_asset['browsers'];
$elements[] = $element;
// The current page will run into IE's limits for CSS assets: work
// around these limits by performing a light form of grouping.
// Once Drupal only needs to support IE10 and later, we can drop this.
else {
// The file CSS asset is ineligible for aggregation: output it in a
// LINK tag.
if (!$css_asset['preprocess']) {
$element = $link_element_defaults;
$element['#attributes']['href'] = file_url_transform_relative(file_create_url($css_asset['data'])) . $query_string_separator . $query_string;
$element['#attributes']['media'] = $css_asset['media'];
$element['#browsers'] = $css_asset['browsers'];
$elements[] = $element;
// The file CSS asset can be aggregated, but hasn't been: combine
// multiple items into as few STYLE tags as possible.
else {
$import = [];
// Start with the current CSS asset, iterate over subsequent CSS
// assets and find which ones have the same 'type', 'group',
// 'preprocess', 'media' and 'browsers' properties.
$j = $i;
$next_css_asset = $css_asset;
$current_ie_group_key = $get_ie_group_key($css_asset);
do {
// The dummy query string needs to be added to the URL to
// control browser-caching. IE7 does not support a media type on
// the @import statement, so we instead specify the media for
// the group on the STYLE tag.
$import[] = '@import url("' . Html::escape(file_url_transform_relative(file_create_url($next_css_asset['data'])) . '?' . $query_string) . '");';
// Move the outer for loop skip the next item, since we
// processed it here.
$i = $j;
// Retrieve next CSS asset, unless there is none: then break.
if ($j + 1 < count($css_assets_keys)) {
$next_css_asset = $css_assets[$css_assets_keys[$j]];
else {
} while ($get_ie_group_key($next_css_asset) == $current_ie_group_key);
// In addition to IE's limit of 31 total CSS inclusion tags, it
// also has a limit of 31 @import statements per STYLE tag.
while (!empty($import)) {
$import_batch = array_slice($import, 0, 31);
$import = array_slice($import, 31);
$element = $style_element_defaults;
// This simplifies the JavaScript regex, allowing each line
// (separated by \n) to be treated as a completely different
// string. This means that we can use ^ and $ on one line at a
// time, and not worry about style tags since they'll never
// match the regex.
$element['#value'] = "\n" . implode("\n", $import_batch) . "\n";
$element['#attributes']['media'] = $css_asset['media'];
$element['#browsers'] = $css_asset['browsers'];
$elements[] = $element;
$element['#attributes']['href'] = file_url_transform_relative(file_create_url($css_asset['data'])) . $query_string_separator . $query_string;
// Output a LINK tag for an external CSS asset. The asset's 'data'
// property contains the full URL.
case 'external':
$element = $link_element_defaults;
$element['#attributes']['href'] = $css_asset['data'];
$element['#attributes']['media'] = $css_asset['media'];
$element['#browsers'] = $css_asset['browsers'];
$elements[] = $element;
throw new \Exception('Invalid CSS asset type.');
$elements[] = $element;
return $elements;
......@@ -89,7 +89,7 @@ public function testAddFiles() {
$rendered_css = $this->renderer->renderPlain($css_render_array);
$rendered_js = $this->renderer->renderPlain($js_render_array);
$query_string = $this->container->get('state')->get('system.css_js_query_string') ?: '0';
$this->assertNotIdentical(strpos($rendered_css, '<link rel="stylesheet" href="' . file_url_transform_relative(file_create_url('core/modules/system/tests/modules/common_test/bar.css')) . '?' . $query_string . '" media="all" />'), FALSE, 'Rendering an external CSS file.');
$this->assertNotIdentical(strpos($rendered_css, '<link rel="stylesheet" media="all" href="' . file_url_transform_relative(file_create_url('core/modules/system/tests/modules/common_test/bar.css')) . '?' . $query_string . '" />'), FALSE, 'Rendering an external CSS file.');
$this->assertNotIdentical(strpos($rendered_js, '<script src="' . file_url_transform_relative(file_create_url('core/modules/system/tests/modules/common_test/foo.js')) . '?' . $query_string . '"></script>'), FALSE, 'Rendering an external JavaScript file.');
......@@ -128,7 +128,7 @@ public function testAddExternalFiles() {
$js_render_array = \Drupal::service('asset.js.collection_renderer')->render($js);
$rendered_css = $this->renderer->renderPlain($css_render_array);
$rendered_js = $this->renderer->renderPlain($js_render_array);
$this->assertNotIdentical(strpos($rendered_css, '<link rel="stylesheet" href="" media="all" />'), FALSE, 'Rendering an external CSS file.');
$this->assertNotIdentical(strpos($rendered_css, '<link rel="stylesheet" media="all" href="" />'), FALSE, 'Rendering an external CSS file.');
$this->assertNotIdentical(strpos($rendered_js, '<script src=""></script>'), FALSE, 'Rendering an external JavaScript file.');
......@@ -473,7 +473,7 @@ public function testAddJsFileWithQueryString() {
$js_render_array = \Drupal::service('asset.js.collection_renderer')->render($js);
$rendered_js = $this->renderer->renderPlain($js_render_array);
$query_string = $this->container->get('state')->get('system.css_js_query_string') ?: '0';
$this->assertNotIdentical(strpos($rendered_css, '<link rel="stylesheet" href="' . str_replace('&', '&amp;', file_url_transform_relative(file_create_url('core/modules/system/tests/modules/common_test/querystring.css?arg1=value1&arg2=value2'))) . '&amp;' . $query_string . '" media="all" />'), FALSE, 'CSS file with query string gets version query string correctly appended..');
$this->assertNotIdentical(strpos($rendered_css, '<link rel="stylesheet" media="all" href="' . str_replace('&', '&amp;', file_url_transform_relative(file_create_url('core/modules/system/tests/modules/common_test/querystring.css?arg1=value1&arg2=value2'))) . '&amp;' . $query_string . '" />'), FALSE, 'CSS file with query string gets version query string correctly appended..');
$this->assertNotIdentical(strpos($rendered_js, '<script src="' . str_replace('&', '&amp;', file_url_transform_relative(file_create_url('core/modules/system/tests/modules/common_test/querystring.js?arg1=value1&arg2=value2'))) . '&amp;' . $query_string . '"></script>'), FALSE, 'JavaScript file with query string gets version query string correctly appended.');
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