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1 <?php
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2
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3 namespace Drupal\big_pipe\Render;
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4
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5 use Drupal\Component\Utility\Crypt;
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6 use Drupal\Component\Utility\Html;
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7 use Drupal\Core\Ajax\AjaxResponse;
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8 use Drupal\Core\Ajax\ReplaceCommand;
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9 use Drupal\Core\Asset\AttachedAssets;
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10 use Drupal\Core\Asset\AttachedAssetsInterface;
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11 use Drupal\Core\Config\ConfigFactoryInterface;
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12 use Drupal\Core\Render\HtmlResponse;
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13 use Drupal\Core\Render\RendererInterface;
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14 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
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15 use Symfony\Component\HttpFoundation\Request;
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16 use Symfony\Component\HttpFoundation\RequestStack;
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17 use Symfony\Component\HttpFoundation\Response;
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18 use Symfony\Component\HttpFoundation\Session\SessionInterface;
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19 use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
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20 use Symfony\Component\HttpKernel\HttpKernelInterface;
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21 use Symfony\Component\HttpKernel\KernelEvents;
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22
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23 /**
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24 * Service for sending an HTML response in chunks (to get faster page loads).
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25 *
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26 * At a high level, BigPipe sends a HTML response in chunks:
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27 * 1. one chunk: everything until just before </body> — this contains BigPipe
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28 * placeholders for the personalized parts of the page. Hence this sends the
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29 * non-personalized parts of the page. Let's call it The Skeleton.
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30 * 2. N chunks: a <script> tag per BigPipe placeholder in The Skeleton.
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31 * 3. one chunk: </body> and everything after it.
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32 *
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33 * This is conceptually identical to Facebook's BigPipe (hence the name).
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34 *
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35 * @see https://www.facebook.com/notes/facebook-engineering/bigpipe-pipelining-web-pages-for-high-performance/389414033919
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36 *
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37 * The major way in which Drupal differs from Facebook's implementation (and
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38 * others) is in its ability to automatically figure out which parts of the page
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39 * can benefit from BigPipe-style delivery. Drupal's render system has the
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40 * concept of "auto-placeholdering": content that is too dynamic is replaced
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41 * with a placeholder that can then be rendered at a later time. On top of that,
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42 * it also has the concept of "placeholder strategies": by default, placeholders
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43 * are replaced on the server side and the response is blocked on all of them
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44 * being replaced. But it's possible to add additional placeholder strategies.
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45 * BigPipe is just another placeholder strategy. Others could be ESI, AJAX …
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46 *
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47 * @see https://www.drupal.org/developing/api/8/render/arrays/cacheability/auto-placeholdering
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48 * @see \Drupal\Core\Render\PlaceholderGeneratorInterface::shouldAutomaticallyPlaceholder()
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49 * @see \Drupal\Core\Render\Placeholder\PlaceholderStrategyInterface
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50 * @see \Drupal\Core\Render\Placeholder\SingleFlushStrategy
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51 * @see \Drupal\big_pipe\Render\Placeholder\BigPipeStrategy
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52 *
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53 * There is also one noteworthy technical addition that Drupal makes. BigPipe as
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54 * described above, and as implemented by Facebook, can only work if JavaScript
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55 * is enabled. The BigPipe module also makes it possible to replace placeholders
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56 * using BigPipe in-situ, without JavaScript. This is not technically BigPipe at
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57 * all; it's just the use of multiple flushes. Since it is able to reuse much of
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58 * the logic though, we choose to call this "no-JS BigPipe".
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59 *
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60 * However, there is also a tangible benefit: some dynamic/expensive content is
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61 * not HTML, but for example a HTML attribute value (or part thereof). It's not
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62 * possible to efficiently replace such content using JavaScript, so "classic"
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63 * BigPipe is out of the question. For example: CSRF tokens in URLs.
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64 *
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65 * This allows us to use both no-JS BigPipe and "classic" BigPipe in the same
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66 * response to maximize the amount of content we can send as early as possible.
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67 *
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68 * Finally, a closer look at the implementation, and how it supports and reuses
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69 * existing Drupal concepts:
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70 * 1. BigPipe placeholders: 1 HtmlResponse + N embedded AjaxResponses.
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71 * - Before a BigPipe response is sent, it is just a HTML response that
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72 * contains BigPipe placeholders. Those placeholders look like
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73 * <span data-big-pipe-placeholder-id="…"></span>. JavaScript is used to
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74 * replace those placeholders.
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75 * Therefore these placeholders are actually sent to the client.
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76 * - The Skeleton of course has attachments, including most notably asset
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77 * libraries. And those we track in drupalSettings.ajaxPageState.libraries —
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78 * so that when we load new content through AJAX, we don't load the same
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79 * asset libraries again. A HTML page can have multiple AJAX responses, each
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80 * of which should take into account the combined AJAX page state of the
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81 * HTML document and all preceding AJAX responses.
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82 * - BigPipe does not make use of multiple AJAX requests/responses. It uses a
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83 * single HTML response. But it is a more long-lived one: The Skeleton is
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84 * sent first, the closing </body> tag is not yet sent, and the connection
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85 * is kept open. Whenever another BigPipe Placeholder is rendered, Drupal
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86 * sends (and so actually appends to the already-sent HTML) something like
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87 * <script type="application/vnd.drupal-ajax">[{"command":"settings","settings":{…}}, {"command":…}.
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88 * - So, for every BigPipe placeholder, we send such a <script
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89 * type="application/vnd.drupal-ajax"> tag. And the contents of that tag is
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90 * exactly like an AJAX response. The BigPipe module has JavaScript that
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91 * listens for these and applies them. Let's call it an Embedded AJAX
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92 * Response (since it is embedded in the HTML response). Now for the
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93 * interesting bit: each of those Embedded AJAX Responses must also take
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94 * into account the cumulative AJAX page state of the HTML document and all
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95 * preceding Embedded AJAX responses.
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96 * 2. No-JS BigPipe placeholders: 1 HtmlResponse + N embedded HtmlResponses.
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97 * - Before a BigPipe response is sent, it is just a HTML response that
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98 * contains no-JS BigPipe placeholders. Those placeholders can take two
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99 * different forms:
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100 * 1. <span data-big-pipe-nojs-placeholder-id="…"></span> if it's a
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101 * placeholder that will be replaced by HTML
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102 * 2. big_pipe_nojs_placeholder_attribute_safe:… if it's a placeholder
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103 * inside a HTML attribute, in which 1. would be invalid (angle brackets
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104 * are not allowed inside HTML attributes)
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105 * No-JS BigPipe placeholders are not replaced using JavaScript, they must
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106 * be replaced upon sending the BigPipe response. So, while the response is
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107 * being sent, upon encountering these placeholders, their corresponding
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108 * placeholder replacements are sent instead.
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109 * Therefore these placeholders are never actually sent to the client.
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110 * - See second bullet of point 1.
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111 * - No-JS BigPipe does not use multiple AJAX requests/responses. It uses a
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112 * single HTML response. But it is a more long-lived one: The Skeleton is
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113 * split into multiple parts, the separators are where the no-JS BigPipe
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114 * placeholders used to be. Whenever another no-JS BigPipe placeholder is
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115 * rendered, Drupal sends (and so actually appends to the already-sent HTML)
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116 * something like
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117 * <link rel="stylesheet" …><script …><content>.
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118 * - So, for every no-JS BigPipe placeholder, we send its associated CSS and
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119 * header JS that has not already been sent (the bottom JS is not yet sent,
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120 * so we can accumulate all of it and send it together at the end). This
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121 * ensures that the markup is rendered as it was originally intended: its
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122 * CSS and JS used to be blocking, and it still is. Let's call it an
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123 * Embedded HTML response. Each of those Embedded HTML Responses must also
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124 * take into account the cumulative AJAX page state of the HTML document and
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125 * all preceding Embedded HTML responses.
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126 * - Finally: any non-critical JavaScript associated with all Embedded HTML
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127 * Responses, i.e. any footer/bottom/non-header JavaScript, is loaded after
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128 * The Skeleton.
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129 *
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130 * Combining all of the above, when using both BigPipe placeholders and no-JS
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131 * BigPipe placeholders, we therefore send: 1 HtmlResponse + M Embedded HTML
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132 * Responses + N Embedded AJAX Responses. Schematically, we send these chunks:
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133 * 1. Byte zero until 1st no-JS placeholder: headers + <html><head /><span>…</span>
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134 * 2. 1st no-JS placeholder replacement: <link rel="stylesheet" …><script …><content>
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135 * 3. Content until 2nd no-JS placeholder: <span>…</span>
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136 * 4. 2nd no-JS placeholder replacement: <link rel="stylesheet" …><script …><content>
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137 * 5. Content until 3rd no-JS placeholder: <span>…</span>
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138 * 6. [… repeat until all no-JS placeholder replacements are sent …]
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139 * 7. Send content after last no-JS placeholder.
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140 * 8. Send script_bottom (markup to load bottom i.e. non-critical JS).
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141 * 9. 1st placeholder replacement: <script type="application/vnd.drupal-ajax">[{"command":"settings","settings":{…}}, {"command":…}
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142 * 10. 2nd placeholder replacement: <script type="application/vnd.drupal-ajax">[{"command":"settings","settings":{…}}, {"command":…}
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143 * 11. [… repeat until all placeholder replacements are sent …]
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144 * 12. Send </body> and everything after it.
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145 * 13. Terminate request/response cycle.
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146 *
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147 * @see \Drupal\big_pipe\EventSubscriber\HtmlResponseBigPipeSubscriber
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148 * @see \Drupal\big_pipe\Render\Placeholder\BigPipeStrategy
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149 */
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150 class BigPipe {
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151
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152 /**
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153 * The BigPipe placeholder replacements start signal.
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154 *
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155 * @var string
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156 */
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157 const START_SIGNAL = '<script type="application/vnd.drupal-ajax" data-big-pipe-event="start"></script>';
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158
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159 /**
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160 * The BigPipe placeholder replacements stop signal.
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161 *
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162 * @var string
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163 */
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164 const STOP_SIGNAL = '<script type="application/vnd.drupal-ajax" data-big-pipe-event="stop"></script>';
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165
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166 /**
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167 * The renderer.
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168 *
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169 * @var \Drupal\Core\Render\RendererInterface
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170 */
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171 protected $renderer;
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172
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173 /**
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174 * The session.
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175 *
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176 * @var \Symfony\Component\HttpFoundation\Session\SessionInterface
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177 */
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178 protected $session;
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179
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180 /**
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181 * The request stack.
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182 *
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183 * @var \Symfony\Component\HttpFoundation\RequestStack
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184 */
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185 protected $requestStack;
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186
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187 /**
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188 * The HTTP kernel.
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189 *
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190 * @var \Symfony\Component\HttpKernel\HttpKernelInterface
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191 */
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192 protected $httpKernel;
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193
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194 /**
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195 * The event dispatcher.
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196 *
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197 * @var \Symfony\Component\EventDispatcher\EventDispatcherInterface
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198 */
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199 protected $eventDispatcher;
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200
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201 /**
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202 * The config factory.
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203 *
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204 * @var \Drupal\Core\Config\ConfigFactoryInterface
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205 */
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206 protected $configFactory;
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207
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208 /**
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209 * Constructs a new BigPipe class.
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210 *
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211 * @param \Drupal\Core\Render\RendererInterface $renderer
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212 * The renderer.
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213 * @param \Symfony\Component\HttpFoundation\Session\SessionInterface $session
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214 * The session.
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215 * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
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216 * The request stack.
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217 * @param \Symfony\Component\HttpKernel\HttpKernelInterface $http_kernel
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218 * The HTTP kernel.
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219 * @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher
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220 * The event dispatcher.
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221 * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
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222 * The config factory.
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223 */
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224 public function __construct(RendererInterface $renderer, SessionInterface $session, RequestStack $request_stack, HttpKernelInterface $http_kernel, EventDispatcherInterface $event_dispatcher, ConfigFactoryInterface $config_factory) {
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225 $this->renderer = $renderer;
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226 $this->session = $session;
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227 $this->requestStack = $request_stack;
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228 $this->httpKernel = $http_kernel;
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229 $this->eventDispatcher = $event_dispatcher;
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230 $this->configFactory = $config_factory;
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231 }
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232
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233 /**
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234 * Performs tasks before sending content (and rendering placeholders).
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235 */
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236 protected function performPreSendTasks() {
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237 // The content in the placeholders may depend on the session, and by the
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238 // time the response is sent (see index.php), the session is already
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239 // closed. Reopen it for the duration that we are rendering placeholders.
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240 $this->session->start();
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241 }
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242
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243 /**
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244 * Performs tasks after sending content (and rendering placeholders).
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245 */
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246 protected function performPostSendTasks() {
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247 // Close the session again.
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248 $this->session->save();
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249 }
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250
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251 /**
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252 * Sends a chunk.
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253 *
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254 * @param string|\Drupal\Core\Render\HtmlResponse $chunk
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255 * The string or response to append. String if there's no cacheability
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256 * metadata or attachments to merge.
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257 */
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258 protected function sendChunk($chunk) {
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259 assert(is_string($chunk) || $chunk instanceof HtmlResponse);
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260 if ($chunk instanceof HtmlResponse) {
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261 print $chunk->getContent();
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262 }
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263 else {
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264 print $chunk;
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265 }
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266 flush();
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267 }
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268
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269 /**
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270 * Sends an HTML response in chunks using the BigPipe technique.
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271 *
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272 * @param \Drupal\big_pipe\Render\BigPipeResponse $response
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273 * The BigPipe response to send.
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274 *
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275 * @internal
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276 * This method should only be invoked by
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277 * \Drupal\big_pipe\Render\BigPipeResponse, which is itself an internal
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278 * class.
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279 */
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280 public function sendContent(BigPipeResponse $response) {
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281 $content = $response->getContent();
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282 $attachments = $response->getAttachments();
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283
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284 // First, gather the BigPipe placeholders that must be replaced.
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285 $placeholders = isset($attachments['big_pipe_placeholders']) ? $attachments['big_pipe_placeholders'] : [];
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286 $nojs_placeholders = isset($attachments['big_pipe_nojs_placeholders']) ? $attachments['big_pipe_nojs_placeholders'] : [];
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287
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288 // BigPipe sends responses using "Transfer-Encoding: chunked". To avoid
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289 // sending already-sent assets, it is necessary to track cumulative assets
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290 // from all previously rendered/sent chunks.
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291 // @see http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.41
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292 $cumulative_assets = AttachedAssets::createFromRenderArray(['#attached' => $attachments]);
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293 $cumulative_assets->setAlreadyLoadedLibraries($attachments['library']);
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294
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295 $this->performPreSendTasks();
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296
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297 // Find the closing </body> tag and get the strings before and after. But be
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298 // careful to use the latest occurrence of the string "</body>", to ensure
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299 // that strings in inline JavaScript or CDATA sections aren't used instead.
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300 $parts = explode('</body>', $content);
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301 $post_body = array_pop($parts);
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302 $pre_body = implode('', $parts);
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303
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304 $this->sendPreBody($pre_body, $nojs_placeholders, $cumulative_assets);
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305 $this->sendPlaceholders($placeholders, $this->getPlaceholderOrder($pre_body, $placeholders), $cumulative_assets);
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306 $this->sendPostBody($post_body);
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307
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308 $this->performPostSendTasks();
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309 }
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310
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311 /**
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312 * Sends everything until just before </body>.
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313 *
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314 * @param string $pre_body
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315 * The HTML response's content until the closing </body> tag.
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316 * @param array $no_js_placeholders
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317 * The no-JS BigPipe placeholders.
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318 * @param \Drupal\Core\Asset\AttachedAssetsInterface $cumulative_assets
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319 * The cumulative assets sent so far; to be updated while rendering no-JS
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320 * BigPipe placeholders.
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321 */
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322 protected function sendPreBody($pre_body, array $no_js_placeholders, AttachedAssetsInterface $cumulative_assets) {
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323 // If there are no no-JS BigPipe placeholders, we can send the pre-</body>
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324 // part of the page immediately.
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325 if (empty($no_js_placeholders)) {
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326 $this->sendChunk($pre_body);
|
Chris@0
|
327 return;
|
Chris@0
|
328 }
|
Chris@0
|
329
|
Chris@0
|
330 // Extract the scripts_bottom markup: the no-JS BigPipe placeholders that we
|
Chris@0
|
331 // will render may attach additional asset libraries, and if so, it will be
|
Chris@0
|
332 // necessary to re-render scripts_bottom.
|
Chris@0
|
333 list($pre_scripts_bottom, $scripts_bottom, $post_scripts_bottom) = explode('<drupal-big-pipe-scripts-bottom-marker>', $pre_body, 3);
|
Chris@0
|
334 $cumulative_assets_initial = clone $cumulative_assets;
|
Chris@0
|
335
|
Chris@0
|
336 $this->sendNoJsPlaceholders($pre_scripts_bottom . $post_scripts_bottom, $no_js_placeholders, $cumulative_assets);
|
Chris@0
|
337
|
Chris@0
|
338 // If additional asset libraries or drupalSettings were attached by any of
|
Chris@0
|
339 // the placeholders, then we need to re-render scripts_bottom.
|
Chris@0
|
340 if ($cumulative_assets_initial != $cumulative_assets) {
|
Chris@0
|
341 // Create a new HtmlResponse. Ensure the CSS and (non-bottom) JS is sent
|
Chris@0
|
342 // before the HTML they're associated with.
|
Chris@0
|
343 // @see \Drupal\Core\Render\HtmlResponseSubscriber
|
Chris@0
|
344 // @see template_preprocess_html()
|
Chris@0
|
345 $js_bottom_placeholder = '<nojs-bigpipe-placeholder-scripts-bottom-placeholder token="' . Crypt::randomBytesBase64(55) . '">';
|
Chris@0
|
346
|
Chris@0
|
347 $html_response = new HtmlResponse();
|
Chris@0
|
348 $html_response->setContent([
|
Chris@0
|
349 '#markup' => BigPipeMarkup::create($js_bottom_placeholder),
|
Chris@0
|
350 '#attached' => [
|
Chris@0
|
351 'drupalSettings' => $cumulative_assets->getSettings(),
|
Chris@0
|
352 'library' => $cumulative_assets->getAlreadyLoadedLibraries(),
|
Chris@0
|
353 'html_response_attachment_placeholders' => [
|
Chris@0
|
354 'scripts_bottom' => $js_bottom_placeholder,
|
Chris@0
|
355 ],
|
Chris@0
|
356 ],
|
Chris@0
|
357 ]);
|
Chris@0
|
358 $html_response->getCacheableMetadata()->setCacheMaxAge(0);
|
Chris@0
|
359
|
Chris@0
|
360 // Push a fake request with the asset libraries loaded so far and dispatch
|
Chris@0
|
361 // KernelEvents::RESPONSE event. This results in the attachments for the
|
Chris@0
|
362 // HTML response being processed by HtmlResponseAttachmentsProcessor and
|
Chris@0
|
363 // hence the HTML to load the bottom JavaScript can be rendered.
|
Chris@0
|
364 $fake_request = $this->requestStack->getMasterRequest()->duplicate();
|
Chris@0
|
365 $html_response = $this->filterEmbeddedResponse($fake_request, $html_response);
|
Chris@0
|
366 $scripts_bottom = $html_response->getContent();
|
Chris@0
|
367 }
|
Chris@0
|
368
|
Chris@0
|
369 $this->sendChunk($scripts_bottom);
|
Chris@0
|
370 }
|
Chris@0
|
371
|
Chris@0
|
372 /**
|
Chris@0
|
373 * Sends no-JS BigPipe placeholders' replacements as embedded HTML responses.
|
Chris@0
|
374 *
|
Chris@0
|
375 * @param string $html
|
Chris@0
|
376 * HTML markup.
|
Chris@0
|
377 * @param array $no_js_placeholders
|
Chris@0
|
378 * Associative array; the no-JS BigPipe placeholders. Keys are the BigPipe
|
Chris@0
|
379 * selectors.
|
Chris@0
|
380 * @param \Drupal\Core\Asset\AttachedAssetsInterface $cumulative_assets
|
Chris@0
|
381 * The cumulative assets sent so far; to be updated while rendering no-JS
|
Chris@0
|
382 * BigPipe placeholders.
|
Chris@0
|
383 *
|
Chris@0
|
384 * @throws \Exception
|
Chris@0
|
385 * If an exception is thrown during the rendering of a placeholder, it is
|
Chris@0
|
386 * caught to allow the other placeholders to still be replaced. But when
|
Chris@0
|
387 * error logging is configured to be verbose, the exception is rethrown to
|
Chris@0
|
388 * simplify debugging.
|
Chris@0
|
389 */
|
Chris@0
|
390 protected function sendNoJsPlaceholders($html, $no_js_placeholders, AttachedAssetsInterface $cumulative_assets) {
|
Chris@0
|
391 // Split the HTML on every no-JS placeholder string.
|
Chris@0
|
392 $prepare_for_preg_split = function ($placeholder_string) {
|
Chris@0
|
393 return '(' . preg_quote($placeholder_string, '/') . ')';
|
Chris@0
|
394 };
|
Chris@0
|
395 $preg_placeholder_strings = array_map($prepare_for_preg_split, array_keys($no_js_placeholders));
|
Chris@0
|
396 $fragments = preg_split('/' . implode('|', $preg_placeholder_strings) . '/', $html, NULL, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);
|
Chris@0
|
397
|
Chris@0
|
398 // Determine how many occurrences there are of each no-JS placeholder.
|
Chris@0
|
399 $placeholder_occurrences = array_count_values(array_intersect($fragments, array_keys($no_js_placeholders)));
|
Chris@0
|
400
|
Chris@0
|
401 // Set up a variable to store the content of placeholders that have multiple
|
Chris@0
|
402 // occurrences.
|
Chris@0
|
403 $multi_occurrence_placeholders_content = [];
|
Chris@0
|
404
|
Chris@0
|
405 foreach ($fragments as $fragment) {
|
Chris@0
|
406 // If the fragment isn't one of the no-JS placeholders, it is the HTML in
|
Chris@0
|
407 // between placeholders and it must be printed & flushed immediately. The
|
Chris@0
|
408 // rest of the logic in the loop handles the placeholders.
|
Chris@0
|
409 if (!isset($no_js_placeholders[$fragment])) {
|
Chris@0
|
410 $this->sendChunk($fragment);
|
Chris@0
|
411 continue;
|
Chris@0
|
412 }
|
Chris@0
|
413
|
Chris@0
|
414 // If there are multiple occurrences of this particular placeholder, and
|
Chris@0
|
415 // this is the second occurrence, we can skip all calculations and just
|
Chris@0
|
416 // send the same content.
|
Chris@0
|
417 if ($placeholder_occurrences[$fragment] > 1 && isset($multi_occurrence_placeholders_content[$fragment])) {
|
Chris@0
|
418 $this->sendChunk($multi_occurrence_placeholders_content[$fragment]);
|
Chris@0
|
419 continue;
|
Chris@0
|
420 }
|
Chris@0
|
421
|
Chris@0
|
422 $placeholder = $fragment;
|
Chris@14
|
423 assert(isset($no_js_placeholders[$placeholder]));
|
Chris@0
|
424 $token = Crypt::randomBytesBase64(55);
|
Chris@0
|
425
|
Chris@0
|
426 // Render the placeholder, but include the cumulative settings assets, so
|
Chris@0
|
427 // we can calculate the overall settings for the entire page.
|
Chris@0
|
428 $placeholder_plus_cumulative_settings = [
|
Chris@0
|
429 'placeholder' => $no_js_placeholders[$placeholder],
|
Chris@0
|
430 'cumulative_settings_' . $token => [
|
Chris@0
|
431 '#attached' => [
|
Chris@0
|
432 'drupalSettings' => $cumulative_assets->getSettings(),
|
Chris@0
|
433 ],
|
Chris@0
|
434 ],
|
Chris@0
|
435 ];
|
Chris@0
|
436 try {
|
Chris@0
|
437 $elements = $this->renderPlaceholder($placeholder, $placeholder_plus_cumulative_settings);
|
Chris@0
|
438 }
|
Chris@0
|
439 catch (\Exception $e) {
|
Chris@0
|
440 if ($this->configFactory->get('system.logging')->get('error_level') === ERROR_REPORTING_DISPLAY_VERBOSE) {
|
Chris@0
|
441 throw $e;
|
Chris@0
|
442 }
|
Chris@0
|
443 else {
|
Chris@0
|
444 trigger_error($e, E_USER_ERROR);
|
Chris@0
|
445 continue;
|
Chris@0
|
446 }
|
Chris@0
|
447 }
|
Chris@0
|
448
|
Chris@0
|
449 // Create a new HtmlResponse. Ensure the CSS and (non-bottom) JS is sent
|
Chris@0
|
450 // before the HTML they're associated with. In other words: ensure the
|
Chris@0
|
451 // critical assets for this placeholder's markup are loaded first.
|
Chris@0
|
452 // @see \Drupal\Core\Render\HtmlResponseSubscriber
|
Chris@0
|
453 // @see template_preprocess_html()
|
Chris@0
|
454 $css_placeholder = '<nojs-bigpipe-placeholder-styles-placeholder token="' . $token . '">';
|
Chris@0
|
455 $js_placeholder = '<nojs-bigpipe-placeholder-scripts-placeholder token="' . $token . '">';
|
Chris@0
|
456 $elements['#markup'] = BigPipeMarkup::create($css_placeholder . $js_placeholder . (string) $elements['#markup']);
|
Chris@0
|
457 $elements['#attached']['html_response_attachment_placeholders']['styles'] = $css_placeholder;
|
Chris@0
|
458 $elements['#attached']['html_response_attachment_placeholders']['scripts'] = $js_placeholder;
|
Chris@0
|
459
|
Chris@0
|
460 $html_response = new HtmlResponse();
|
Chris@0
|
461 $html_response->setContent($elements);
|
Chris@0
|
462 $html_response->getCacheableMetadata()->setCacheMaxAge(0);
|
Chris@0
|
463
|
Chris@0
|
464 // Push a fake request with the asset libraries loaded so far and dispatch
|
Chris@0
|
465 // KernelEvents::RESPONSE event. This results in the attachments for the
|
Chris@0
|
466 // HTML response being processed by HtmlResponseAttachmentsProcessor and
|
Chris@0
|
467 // hence:
|
Chris@0
|
468 // - the HTML to load the CSS can be rendered.
|
Chris@0
|
469 // - the HTML to load the JS (at the top) can be rendered.
|
Chris@0
|
470 $fake_request = $this->requestStack->getMasterRequest()->duplicate();
|
Chris@0
|
471 $fake_request->request->set('ajax_page_state', ['libraries' => implode(',', $cumulative_assets->getAlreadyLoadedLibraries())]);
|
Chris@0
|
472 try {
|
Chris@0
|
473 $html_response = $this->filterEmbeddedResponse($fake_request, $html_response);
|
Chris@0
|
474 }
|
Chris@0
|
475 catch (\Exception $e) {
|
Chris@0
|
476 if ($this->configFactory->get('system.logging')->get('error_level') === ERROR_REPORTING_DISPLAY_VERBOSE) {
|
Chris@0
|
477 throw $e;
|
Chris@0
|
478 }
|
Chris@0
|
479 else {
|
Chris@0
|
480 trigger_error($e, E_USER_ERROR);
|
Chris@0
|
481 continue;
|
Chris@0
|
482 }
|
Chris@0
|
483 }
|
Chris@0
|
484
|
Chris@0
|
485 // Send this embedded HTML response.
|
Chris@0
|
486 $this->sendChunk($html_response);
|
Chris@0
|
487
|
Chris@0
|
488 // Another placeholder was rendered and sent, track the set of asset
|
Chris@0
|
489 // libraries sent so far. Any new settings also need to be tracked, so
|
Chris@0
|
490 // they can be sent in ::sendPreBody().
|
Chris@0
|
491 $cumulative_assets->setAlreadyLoadedLibraries(array_merge($cumulative_assets->getAlreadyLoadedLibraries(), $html_response->getAttachments()['library']));
|
Chris@0
|
492 $cumulative_assets->setSettings($html_response->getAttachments()['drupalSettings']);
|
Chris@0
|
493
|
Chris@0
|
494 // If there are multiple occurrences of this particular placeholder, track
|
Chris@0
|
495 // the content that was sent, so we can skip all calculations for the next
|
Chris@0
|
496 // occurrence.
|
Chris@0
|
497 if ($placeholder_occurrences[$fragment] > 1) {
|
Chris@0
|
498 $multi_occurrence_placeholders_content[$fragment] = $html_response->getContent();
|
Chris@0
|
499 }
|
Chris@0
|
500 }
|
Chris@0
|
501 }
|
Chris@0
|
502
|
Chris@0
|
503 /**
|
Chris@0
|
504 * Sends BigPipe placeholders' replacements as embedded AJAX responses.
|
Chris@0
|
505 *
|
Chris@0
|
506 * @param array $placeholders
|
Chris@0
|
507 * Associative array; the BigPipe placeholders. Keys are the BigPipe
|
Chris@0
|
508 * placeholder IDs.
|
Chris@0
|
509 * @param array $placeholder_order
|
Chris@0
|
510 * Indexed array; the order in which the BigPipe placeholders must be sent.
|
Chris@0
|
511 * Values are the BigPipe placeholder IDs. (These values correspond to keys
|
Chris@0
|
512 * in $placeholders.)
|
Chris@0
|
513 * @param \Drupal\Core\Asset\AttachedAssetsInterface $cumulative_assets
|
Chris@0
|
514 * The cumulative assets sent so far; to be updated while rendering BigPipe
|
Chris@0
|
515 * placeholders.
|
Chris@0
|
516 *
|
Chris@0
|
517 * @throws \Exception
|
Chris@0
|
518 * If an exception is thrown during the rendering of a placeholder, it is
|
Chris@0
|
519 * caught to allow the other placeholders to still be replaced. But when
|
Chris@0
|
520 * error logging is configured to be verbose, the exception is rethrown to
|
Chris@0
|
521 * simplify debugging.
|
Chris@0
|
522 */
|
Chris@0
|
523 protected function sendPlaceholders(array $placeholders, array $placeholder_order, AttachedAssetsInterface $cumulative_assets) {
|
Chris@0
|
524 // Return early if there are no BigPipe placeholders to send.
|
Chris@0
|
525 if (empty($placeholders)) {
|
Chris@0
|
526 return;
|
Chris@0
|
527 }
|
Chris@0
|
528
|
Chris@0
|
529 // Send the start signal.
|
Chris@0
|
530 $this->sendChunk("\n" . static::START_SIGNAL . "\n");
|
Chris@0
|
531
|
Chris@0
|
532 // A BigPipe response consists of a HTML response plus multiple embedded
|
Chris@0
|
533 // AJAX responses. To process the attachments of those AJAX responses, we
|
Chris@0
|
534 // need a fake request that is identical to the master request, but with
|
Chris@0
|
535 // one change: it must have the right Accept header, otherwise the work-
|
Chris@0
|
536 // around for a bug in IE9 will cause not JSON, but <textarea>-wrapped JSON
|
Chris@0
|
537 // to be returned.
|
Chris@0
|
538 // @see \Drupal\Core\EventSubscriber\AjaxResponseSubscriber::onResponse()
|
Chris@0
|
539 $fake_request = $this->requestStack->getMasterRequest()->duplicate();
|
Chris@0
|
540 $fake_request->headers->set('Accept', 'application/vnd.drupal-ajax');
|
Chris@0
|
541
|
Chris@0
|
542 foreach ($placeholder_order as $placeholder_id) {
|
Chris@0
|
543 if (!isset($placeholders[$placeholder_id])) {
|
Chris@0
|
544 continue;
|
Chris@0
|
545 }
|
Chris@0
|
546
|
Chris@0
|
547 // Render the placeholder.
|
Chris@0
|
548 $placeholder_render_array = $placeholders[$placeholder_id];
|
Chris@0
|
549 try {
|
Chris@0
|
550 $elements = $this->renderPlaceholder($placeholder_id, $placeholder_render_array);
|
Chris@0
|
551 }
|
Chris@0
|
552 catch (\Exception $e) {
|
Chris@0
|
553 if ($this->configFactory->get('system.logging')->get('error_level') === ERROR_REPORTING_DISPLAY_VERBOSE) {
|
Chris@0
|
554 throw $e;
|
Chris@0
|
555 }
|
Chris@0
|
556 else {
|
Chris@0
|
557 trigger_error($e, E_USER_ERROR);
|
Chris@0
|
558 continue;
|
Chris@0
|
559 }
|
Chris@0
|
560 }
|
Chris@0
|
561
|
Chris@0
|
562 // Create a new AjaxResponse.
|
Chris@0
|
563 $ajax_response = new AjaxResponse();
|
Chris@0
|
564 // JavaScript's querySelector automatically decodes HTML entities in
|
Chris@0
|
565 // attributes, so we must decode the entities of the current BigPipe
|
Chris@0
|
566 // placeholder ID (which has HTML entities encoded since we use it to find
|
Chris@0
|
567 // the placeholders).
|
Chris@0
|
568 $big_pipe_js_placeholder_id = Html::decodeEntities($placeholder_id);
|
Chris@0
|
569 $ajax_response->addCommand(new ReplaceCommand(sprintf('[data-big-pipe-placeholder-id="%s"]', $big_pipe_js_placeholder_id), $elements['#markup']));
|
Chris@0
|
570 $ajax_response->setAttachments($elements['#attached']);
|
Chris@0
|
571
|
Chris@0
|
572 // Push a fake request with the asset libraries loaded so far and dispatch
|
Chris@0
|
573 // KernelEvents::RESPONSE event. This results in the attachments for the
|
Chris@0
|
574 // AJAX response being processed by AjaxResponseAttachmentsProcessor and
|
Chris@0
|
575 // hence:
|
Chris@0
|
576 // - the necessary AJAX commands to load the necessary missing asset
|
Chris@0
|
577 // libraries and updated AJAX page state are added to the AJAX response
|
Chris@0
|
578 // - the attachments associated with the response are finalized, which
|
Chris@0
|
579 // allows us to track the total set of asset libraries sent in the
|
Chris@0
|
580 // initial HTML response plus all embedded AJAX responses sent so far.
|
Chris@0
|
581 $fake_request->request->set('ajax_page_state', ['libraries' => implode(',', $cumulative_assets->getAlreadyLoadedLibraries())] + $cumulative_assets->getSettings()['ajaxPageState']);
|
Chris@0
|
582 try {
|
Chris@0
|
583 $ajax_response = $this->filterEmbeddedResponse($fake_request, $ajax_response);
|
Chris@0
|
584 }
|
Chris@0
|
585 catch (\Exception $e) {
|
Chris@0
|
586 if ($this->configFactory->get('system.logging')->get('error_level') === ERROR_REPORTING_DISPLAY_VERBOSE) {
|
Chris@0
|
587 throw $e;
|
Chris@0
|
588 }
|
Chris@0
|
589 else {
|
Chris@0
|
590 trigger_error($e, E_USER_ERROR);
|
Chris@0
|
591 continue;
|
Chris@0
|
592 }
|
Chris@0
|
593 }
|
Chris@0
|
594
|
Chris@0
|
595 // Send this embedded AJAX response.
|
Chris@0
|
596 $json = $ajax_response->getContent();
|
Chris@0
|
597 $output = <<<EOF
|
Chris@0
|
598 <script type="application/vnd.drupal-ajax" data-big-pipe-replacement-for-placeholder-with-id="$placeholder_id">
|
Chris@0
|
599 $json
|
Chris@0
|
600 </script>
|
Chris@0
|
601 EOF;
|
Chris@0
|
602 $this->sendChunk($output);
|
Chris@0
|
603
|
Chris@0
|
604 // Another placeholder was rendered and sent, track the set of asset
|
Chris@0
|
605 // libraries sent so far. Any new settings are already sent; we don't need
|
Chris@0
|
606 // to track those.
|
Chris@0
|
607 if (isset($ajax_response->getAttachments()['drupalSettings']['ajaxPageState']['libraries'])) {
|
Chris@0
|
608 $cumulative_assets->setAlreadyLoadedLibraries(explode(',', $ajax_response->getAttachments()['drupalSettings']['ajaxPageState']['libraries']));
|
Chris@0
|
609 }
|
Chris@0
|
610 }
|
Chris@0
|
611
|
Chris@0
|
612 // Send the stop signal.
|
Chris@0
|
613 $this->sendChunk("\n" . static::STOP_SIGNAL . "\n");
|
Chris@0
|
614 }
|
Chris@0
|
615
|
Chris@0
|
616 /**
|
Chris@0
|
617 * Filters the given embedded response, using the cumulative AJAX page state.
|
Chris@0
|
618 *
|
Chris@0
|
619 * @param \Symfony\Component\HttpFoundation\Request $fake_request
|
Chris@0
|
620 * A fake subrequest that contains the cumulative AJAX page state of the
|
Chris@0
|
621 * HTML document and all preceding Embedded HTML or AJAX responses.
|
Chris@0
|
622 * @param \Symfony\Component\HttpFoundation\Response|\Drupal\Core\Render\HtmlResponse|\Drupal\Core\Ajax\AjaxResponse $embedded_response
|
Chris@0
|
623 * Either a HTML response or an AJAX response that will be embedded in the
|
Chris@0
|
624 * overall HTML response.
|
Chris@0
|
625 *
|
Chris@0
|
626 * @return \Symfony\Component\HttpFoundation\Response
|
Chris@0
|
627 * The filtered response, which will load only the assets that $fake_request
|
Chris@0
|
628 * did not indicate to already have been loaded, plus the updated cumulative
|
Chris@0
|
629 * AJAX page state.
|
Chris@0
|
630 */
|
Chris@0
|
631 protected function filterEmbeddedResponse(Request $fake_request, Response $embedded_response) {
|
Chris@14
|
632 assert($embedded_response instanceof HtmlResponse || $embedded_response instanceof AjaxResponse);
|
Chris@0
|
633 return $this->filterResponse($fake_request, HttpKernelInterface::SUB_REQUEST, $embedded_response);
|
Chris@0
|
634 }
|
Chris@0
|
635
|
Chris@0
|
636 /**
|
Chris@0
|
637 * Filters the given response.
|
Chris@0
|
638 *
|
Chris@0
|
639 * @param \Symfony\Component\HttpFoundation\Request $request
|
Chris@0
|
640 * The request for which a response is being sent.
|
Chris@0
|
641 * @param int $request_type
|
Chris@0
|
642 * The request type. Can either be
|
Chris@0
|
643 * \Symfony\Component\HttpKernel\HttpKernelInterface::MASTER_REQUEST or
|
Chris@0
|
644 * \Symfony\Component\HttpKernel\HttpKernelInterface::SUB_REQUEST.
|
Chris@0
|
645 * @param \Symfony\Component\HttpFoundation\Response $response
|
Chris@0
|
646 * The response to filter.
|
Chris@0
|
647 *
|
Chris@0
|
648 * @return \Symfony\Component\HttpFoundation\Response
|
Chris@0
|
649 * The filtered response.
|
Chris@0
|
650 */
|
Chris@0
|
651 protected function filterResponse(Request $request, $request_type, Response $response) {
|
Chris@14
|
652 assert($request_type === HttpKernelInterface::MASTER_REQUEST || $request_type === HttpKernelInterface::SUB_REQUEST);
|
Chris@0
|
653 $this->requestStack->push($request);
|
Chris@0
|
654 $event = new FilterResponseEvent($this->httpKernel, $request, $request_type, $response);
|
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655 $this->eventDispatcher->dispatch(KernelEvents::RESPONSE, $event);
|
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656 $filtered_response = $event->getResponse();
|
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|
657 $this->requestStack->pop();
|
Chris@0
|
658 return $filtered_response;
|
Chris@0
|
659 }
|
Chris@0
|
660
|
Chris@0
|
661 /**
|
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|
662 * Sends </body> and everything after it.
|
Chris@0
|
663 *
|
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|
664 * @param string $post_body
|
Chris@0
|
665 * The HTML response's content after the closing </body> tag.
|
Chris@0
|
666 */
|
Chris@0
|
667 protected function sendPostBody($post_body) {
|
Chris@0
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668 $this->sendChunk('</body>' . $post_body);
|
Chris@0
|
669 }
|
Chris@0
|
670
|
Chris@0
|
671 /**
|
Chris@0
|
672 * Renders a placeholder, and just that placeholder.
|
Chris@0
|
673 *
|
Chris@0
|
674 * BigPipe renders placeholders independently of the rest of the content, so
|
Chris@0
|
675 * it needs to be able to render placeholders by themselves.
|
Chris@0
|
676 *
|
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|
677 * @param string $placeholder
|
Chris@0
|
678 * The placeholder to render.
|
Chris@0
|
679 * @param array $placeholder_render_array
|
Chris@0
|
680 * The render array associated with that placeholder.
|
Chris@0
|
681 *
|
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|
682 * @return array
|
Chris@0
|
683 * The render array representing the rendered placeholder.
|
Chris@0
|
684 *
|
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|
685 * @see \Drupal\Core\Render\RendererInterface::renderPlaceholder()
|
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|
686 */
|
Chris@0
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687 protected function renderPlaceholder($placeholder, array $placeholder_render_array) {
|
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|
688 $elements = [
|
Chris@0
|
689 '#markup' => $placeholder,
|
Chris@0
|
690 '#attached' => [
|
Chris@0
|
691 'placeholders' => [
|
Chris@0
|
692 $placeholder => $placeholder_render_array,
|
Chris@0
|
693 ],
|
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694 ],
|
Chris@0
|
695 ];
|
Chris@0
|
696 return $this->renderer->renderPlaceholder($placeholder, $elements);
|
Chris@0
|
697 }
|
Chris@0
|
698
|
Chris@0
|
699 /**
|
Chris@0
|
700 * Gets the BigPipe placeholder order.
|
Chris@0
|
701 *
|
Chris@0
|
702 * Determines the order in which BigPipe placeholders must be replaced.
|
Chris@0
|
703 *
|
Chris@0
|
704 * @param string $html
|
Chris@0
|
705 * HTML markup.
|
Chris@0
|
706 * @param array $placeholders
|
Chris@0
|
707 * Associative array; the BigPipe placeholders. Keys are the BigPipe
|
Chris@0
|
708 * placeholder IDs.
|
Chris@0
|
709 *
|
Chris@0
|
710 * @return array
|
Chris@0
|
711 * Indexed array; the order in which the BigPipe placeholders must be sent.
|
Chris@0
|
712 * Values are the BigPipe placeholder IDs. Note that only unique
|
Chris@0
|
713 * placeholders are kept: if the same placeholder occurs multiple times, we
|
Chris@0
|
714 * only keep the first occurrence.
|
Chris@0
|
715 */
|
Chris@0
|
716 protected function getPlaceholderOrder($html, $placeholders) {
|
Chris@0
|
717 $fragments = explode('<span data-big-pipe-placeholder-id="', $html);
|
Chris@0
|
718 array_shift($fragments);
|
Chris@0
|
719 $placeholder_ids = [];
|
Chris@0
|
720
|
Chris@0
|
721 foreach ($fragments as $fragment) {
|
Chris@0
|
722 $t = explode('"></span>', $fragment, 2);
|
Chris@0
|
723 $placeholder_id = $t[0];
|
Chris@0
|
724 $placeholder_ids[] = $placeholder_id;
|
Chris@0
|
725 }
|
Chris@0
|
726 $placeholder_ids = array_unique($placeholder_ids);
|
Chris@0
|
727
|
Chris@0
|
728 // The 'status messages' placeholder needs to be special cased, because it
|
Chris@0
|
729 // depends on global state that can be modified when other placeholders are
|
Chris@0
|
730 // being rendered: any code can add messages to render.
|
Chris@0
|
731 // This violates the principle that each lazy builder must be able to render
|
Chris@0
|
732 // itself in isolation, and therefore in any order. However, we cannot
|
Chris@17
|
733 // change the way \Drupal\Core\Messenger\MessengerInterface::addMessage()
|
Chris@17
|
734 // works in the Drupal 8 cycle. So we have to accommodate its special needs.
|
Chris@0
|
735 // Allowing placeholders to be rendered in a particular order (in this case:
|
Chris@0
|
736 // last) would violate this isolation principle. Thus a monopoly is granted
|
Chris@0
|
737 // to this one special case, with this hard-coded solution.
|
Chris@0
|
738 // @see \Drupal\Core\Render\Element\StatusMessages
|
Chris@0
|
739 // @see \Drupal\Core\Render\Renderer::replacePlaceholders()
|
Chris@0
|
740 // @see https://www.drupal.org/node/2712935#comment-11368923
|
Chris@0
|
741 $message_placeholder_ids = [];
|
Chris@0
|
742 foreach ($placeholders as $placeholder_id => $placeholder_element) {
|
Chris@0
|
743 if (isset($placeholder_element['#lazy_builder']) && $placeholder_element['#lazy_builder'][0] === 'Drupal\Core\Render\Element\StatusMessages::renderMessages') {
|
Chris@0
|
744 $message_placeholder_ids[] = $placeholder_id;
|
Chris@0
|
745 }
|
Chris@0
|
746 }
|
Chris@0
|
747
|
Chris@0
|
748 // Return placeholder IDs in DOM order, but with the 'status messages'
|
Chris@0
|
749 // placeholders at the end, if they are present.
|
Chris@0
|
750 $ordered_placeholder_ids = array_merge(
|
Chris@0
|
751 array_diff($placeholder_ids, $message_placeholder_ids),
|
Chris@0
|
752 array_intersect($placeholder_ids, $message_placeholder_ids)
|
Chris@0
|
753 );
|
Chris@0
|
754 return $ordered_placeholder_ids;
|
Chris@0
|
755 }
|
Chris@0
|
756
|
Chris@0
|
757 }
|