public function CssCollectionRenderer::render in Advanced CSS/JS Aggregation 8.2
Renders an asset collection.
Parameters
array $assets: An asset collection.
Return value
array A render array to render the asset collection.
Overrides CssCollectionRenderer::render
File
- src/
Asset/ CssCollectionRenderer.php, line 37
Class
Namespace
Drupal\advagg\AssetCode
public function render(array $css_assets) {
$elements = [
'prefetch' => [],
];
$prefetch = $this->config
->get('dns_prefetch');
// A dummy query-string is added to filenames, to gain control over
// browser-caching. The string changes on every update or full cache
// flush, forcing browsers to load a new copy of the files, as the
// URL changed.
$query_string = $this->state
->get('system.css_js_query_string') ?: '0';
// Defaults skeleton for elements.
$link_element_defaults = [
'#type' => 'html_tag',
'#tag' => 'link',
'#attributes' => [
'rel' => 'stylesheet',
],
];
$style_element_defaults = [
'#type' => 'html_tag',
'#tag' => 'style',
];
$prefetch_element_defaults = [
'#type' => 'html_tag',
'#tag' => 'link',
'#attributes' => [
'rel' => 'dns-prefetch',
],
];
// For filthy IE hack.
$current_ie_group_key = NULL;
$get_ie_group_key = function ($css_asset) {
return [
$css_asset['type'],
$css_asset['preprocess'],
$css_asset['group'],
$css_asset['media'],
$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', 'inline', 'browsers' and if
// set also 'media') and output this group into as few STYLE tags
// as possible (each STYLE tag must have less than 31 @import
// statements).
case 'file':
// Prefetch contained domains (ie calls to url()).
if ($prefetch && !empty($css_asset['dns_prefetch'])) {
foreach ($css_asset['dns_prefetch'] as $domain) {
$element = $prefetch_element_defaults;
$element['#attributes']['href'] = '//' . $domain;
$elements['prefetch'][] = $element;
if ($domain == 'fonts.googleapis.com') {
// Add fonts.gstatic.com when fonts.googleapis.com is added.
$element['#attributes']['href'] = 'https://fonts.gstatic.com';
array_unshift($elements, $element);
}
}
}
// 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['#browsers'] = $css_asset['browsers'];
if (isset($css_asset['media'])) {
$element['#attributes']['media'] = $css_asset['media'];
}
$element['#inline'] = !empty($css_asset['inline']) ? TRUE : FALSE;
$elements[] = $element;
}
else {
// The file CSS asset is ineligible for aggregation: output it in a
// LINK tag.
if (!$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'];
$element['#inline'] = !empty($css_asset['inline']) ? TRUE : FALSE;
$elements[] = $element;
}
else {
$import = [];
// Start with the current CSS asset, iterate over subsequent CSS
// assets and find which ones have the same 'type', 'group',
// 'preprocess', 'inline', 'browsers' properties and depending on
// settings, also 'media'.
$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)) {
$j++;
$next_css_asset = $css_assets[$css_assets_keys[$j]];
}
else {
break;
}
} while ($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", $import_batch) . "\n";
if (isset($css_asset['media'])) {
$element['#attributes']['media'] = $css_asset['media'];
}
$element['#browsers'] = $css_asset['browsers'];
$elements[] = $element;
}
}
}
break;
// 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[] = $element;
if ($prefetch) {
$element = $prefetch_element_defaults;
$element['#attributes']['href'] = '//' . parse_url($css_asset['data'], PHP_URL_HOST);
$elements['prefetch'][] = $element;
if ($element['#attributes']['href'] == 'fonts.googleapis.com') {
// Add fonts.gstatic.com when fonts.googleapis.com is added.
$element['#attributes']['href'] = 'https://fonts.gstatic.com';
$elements['prefetch'][] = $element;
}
}
break;
default:
throw new \Exception('Invalid CSS asset type.');
}
}
if (empty($elements['prefetch'])) {
unset($elements['prefetch']);
}
return $elements;
}