BigPipeStrategy.php 10.8 KB
 effulgentsia committed Mar 01, 2016 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107  tag, chunks 2 to (N-1) are replacement * values for the placeholders, chunk N is and everything after it. * 2. with JavaScript disabled: #attached[big_pipe_nojs_placeholders]. Their * replacements are streamed in situ: chunk 1 is the entire page until the * first no-JS BigPipe placeholder, chunk 2 is the replacement for that * placeholder, chunk 3 is the chunk from after that placeholder until the * next no-JS BigPipe placeholder, et cetera. * * JS BigPipe placeholders are preferred because they result in better perceived * performance: the entire page can be sent, minus the placeholders. But it * requires JavaScript. * * No-JS BigPipe placeholders result in more visible blocking: only the part of * the page can be sent until the first placeholder, after it is rendered until * the second, et cetera. (In essence: multiple flushes.) * * Finally, both of those substrategies can also be combined: some placeholders * live in places that cannot be efficiently replaced by JavaScript, for example * CSRF tokens in URLs. Using no-JS BigPipe placeholders in those cases allows * the first part of the page (until the first no-JS BigPipe placeholder) to be * sent sooner than when they would be replaced using SingleFlushStrategy, which * would prevent anything from being sent until all those non-HTML placeholders * would have been replaced. * * See \Drupal\big_pipe\Render\BigPipe for detailed documentation on how those * different placeholders are actually replaced. * * @see \Drupal\big_pipe\Render\BigPipeInterface */ class BigPipeStrategy implements PlaceholderStrategyInterface { /** * BigPipe no-JS cookie name. */ const NOJS_COOKIE = 'big_pipe_nojs'; /** * The session configuration. * * @var \Drupal\Core\Session\SessionConfigurationInterface */ protected $sessionConfiguration; /** * The request stack. * * @var \Symfony\Component\HttpFoundation\RequestStack */ protected$requestStack; /** * The current route match. * * @var \Drupal\Core\Routing\RouteMatchInterface */ protected $routeMatch; /** * Constructs a new BigPipeStrategy class. * * @param \Drupal\Core\Session\SessionConfigurationInterface$session_configuration * The session configuration. * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack * The request stack. * @param \Drupal\Core\Routing\RouteMatchInterface$route_match * The current route match. */ public function __construct(SessionConfigurationInterface $session_configuration, RequestStack$request_stack, RouteMatchInterface $route_match) {$this->sessionConfiguration = $session_configuration;$this->requestStack = $request_stack;$this->routeMatch = $route_match; } /** * {@inheritdoc} */ public function processPlaceholders(array$placeholders) {  catch committed Apr 28, 2016 108 109 110 111 112 113 114  $request =$this->requestStack->getCurrentRequest(); // @todo remove this check when https://www.drupal.org/node/2367555 lands. if (!$request->isMethodSafe()) { return []; }  effulgentsia committed Mar 01, 2016 115 116 117 118 119  // Routes can opt out from using the BigPipe HTML delivery technique. if ($this->routeMatch->getRouteObject()->getOption('_no_big_pipe')) { return []; }  catch committed Apr 28, 2016 120  if (!$this->sessionConfiguration->hasSession($request)) {  effulgentsia committed Mar 01, 2016 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223  return []; } return $this->doProcessPlaceholders($placeholders); } /** * Transforms placeholders to BigPipe placeholders, either no-JS or JS. * * @param array $placeholders * The placeholders to process. * * @return array * The BigPipe placeholders. */ protected function doProcessPlaceholders(array$placeholders) { $overridden_placeholders = []; foreach ($placeholders as $placeholder =>$placeholder_elements) { // BigPipe uses JavaScript and the DOM to find the placeholder to replace. // This means finding the placeholder to replace must be efficient. Most // placeholders are HTML, which we can find efficiently thanks to the // querySelector API. But some placeholders are HTML attribute values or // parts thereof, and potentially even plain text in DOM text nodes. For // BigPipe's JavaScript to find those placeholders, it would need to // iterate over all DOM text nodes. This is highly inefficient. Therefore, // the BigPipe placeholder strategy only converts HTML placeholders into // BigPipe placeholders. The other placeholders need to be replaced on the // server, not via BigPipe. // @see \Drupal\Core\Access\RouteProcessorCsrf::renderPlaceholderCsrfToken() // @see \Drupal\Core\Form\FormBuilder::renderFormTokenPlaceholder() // @see \Drupal\Core\Form\FormBuilder::renderPlaceholderFormAction() if ($placeholder[0] !== '<' ||$placeholder !== Html::normalize($placeholder)) {$overridden_placeholders[$placeholder] = static::createBigPipeNoJsPlaceholder($placeholder, $placeholder_elements, TRUE); } else { // If the current request/session doesn't have JavaScript, fall back to // no-JS BigPipe. if ($this->requestStack->getCurrentRequest()->cookies->has(static::NOJS_COOKIE)) { $overridden_placeholders[$placeholder] = static::createBigPipeNoJsPlaceholder($placeholder,$placeholder_elements, FALSE); } else { $overridden_placeholders[$placeholder] = static::createBigPipeJsPlaceholder($placeholder,$placeholder_elements); } $overridden_placeholders[$placeholder]['#cache']['contexts'][] = 'cookies:' . static::NOJS_COOKIE; } } return $overridden_placeholders; } /** * Creates a BigPipe JS placeholder. * * @param string$original_placeholder * The original placeholder. * @param array $placeholder_render_array * The render array for a placeholder. * * @return array * The resulting BigPipe JS placeholder render array. */ protected static function createBigPipeJsPlaceholder($original_placeholder, array $placeholder_render_array) {$big_pipe_placeholder_id = static::generateBigPipePlaceholderId($original_placeholder,$placeholder_render_array); return [ '#markup' => '
', '#cache' => [ 'max-age' => 0, 'contexts' => [ 'session.exists', ], ], '#attached' => [ 'library' => [ 'big_pipe/big_pipe', ], // Inform BigPipe' JavaScript known BigPipe placeholder IDs (a whitelist). 'drupalSettings' => [ 'bigPipePlaceholderIds' => [$big_pipe_placeholder_id => TRUE], ], 'big_pipe_placeholders' => [ Html::escape($big_pipe_placeholder_id) => $placeholder_render_array, ], ], ]; } /** * Creates a BigPipe no-JS placeholder. * * @param string$original_placeholder * The original placeholder. * @param array $placeholder_render_array * The render array for a placeholder. * @param bool$placeholder_must_be_attribute_safe * Whether the placeholder must be safe for use in a HTML attribute (in case * it's a placeholder for a HTML attribute value or a subset of it). * * @return array * The resulting BigPipe no-JS placeholder render array. */ protected static function createBigPipeNoJsPlaceholder($original_placeholder, array$placeholder_render_array, $placeholder_must_be_attribute_safe = FALSE) { if (!$placeholder_must_be_attribute_safe) {  alexpott committed May 05, 2016 224  $big_pipe_placeholder = ' ';  effulgentsia committed Mar 01, 2016 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275  } else {$big_pipe_placeholder = 'big_pipe_nojs_placeholder_attribute_safe:' . Html::escape($original_placeholder); } return [ '#markup' =>$big_pipe_placeholder, '#cache' => [ 'max-age' => 0, 'contexts' => [ 'session.exists', ], ], '#attached' => [ 'big_pipe_nojs_placeholders' => [ $big_pipe_placeholder =>$placeholder_render_array, ], ], ]; } /** * Generates a BigPipe placeholder ID. * * @param string $original_placeholder * The original placeholder. * @param array$placeholder_render_array * The render array for a placeholder. * * @return string * The generated BigPipe placeholder ID. */ protected static function generateBigPipePlaceholderId($original_placeholder, array$placeholder_render_array) { // Generate a BigPipe placeholder ID (to be used by BigPipe's JavaScript). // @see \Drupal\Core\Render\PlaceholderGenerator::createPlaceholder() if (isset($placeholder_render_array['#lazy_builder'])) {$callback = $placeholder_render_array['#lazy_builder'][0];$arguments = $placeholder_render_array['#lazy_builder'][1];$token = hash('crc32b', serialize($placeholder_render_array)); return UrlHelper::buildQuery(['callback' =>$callback, 'args' => $arguments, 'token' =>$token]); } // When the placeholder's render array is not using a #lazy_builder, // anything could be in there: only #lazy_builder has a strict contract that // allows us to create a more sane selector. Therefore, simply the original // placeholder into a usable placeholder ID, at the cost of it being obtuse. else { return Html::getId(\$original_placeholder); } } }