Issue #2009898 by swim: Port Boost for Drupal 8

README.md

+## About
+Drupal 8 port of the fantastic D7 Boost module.
+
+
+## Installation
+Download and install like any D8 module. Once installed visit a page as an anonymous user to
+generate a local cache file. Check for the X-Boost response header to confirm it's working. There
+are two X-Boost response headers to look for; partial and full. Patial means that PHP is still executing
+and that the apache or nginx config has not been applied correctly.
+
+
+## Legend
+X-Boost-Cache: partial - bad
+
+X-Boost-Cache: full - good
+
+
+## Nginx config
+The following is a very basic example of an nginx configuration for use with Boost.
+
+```
+server {
+  server_name mydomain.com;
+  access_log /srv/www/mydomain.com/logs/access.log;
+  error_log /srv/www/mydomain.com/logs/error.log;
+  root /srv/www/mydomain.com/public_html;
+
+  fastcgi_param SCRIPT_NAME $fastcgi_script_name;
+
+  location ~ (^|/)\. {
+    return 403;
+  }
+    
+  location / {
+    index index.html index.php;
+    expires max;
+
+    set $request_url $request_uri;
+    if ($request_uri ~ ^/admin/(.*)$) {
+      rewrite ^ /index.php;
+    }
+
+    location ~* ^(?:.+\.(?:htaccess|make|txt|engine|inc|info|install|module|profile|po|pot|sh|.*sql|test|theme|tpl(?:\.php)?|xtmpl)|code-style\.pl|/Entries.*|/Repository|/Root|/Tag|/Template)$ {
+      return 404;
+    }
+
+    add_header X-Boost-Cache "full";
+    try_files $uri @rewrite;
+  }
+
+  location @rewrite {
+    gzip_static on;
+
+    if ($request_method = POST) {
+      rewrite ^ /index.php;
+    }
+
+    set $boost_uri "${request_uri}.html";
+    try_files ^ /sites/default/files/boost$boost_uri @drupal;
+  }
+
+  location @drupal {
+    rewrite ^ /index.php;
+  }
+
+  location ~ \.php$ {
+    include /etc/nginx/fastcgi_params;
+    fastcgi_pass  127.0.0.1:9000;
+    fastcgi_index index.php;
+    fastcgi_pass_header Set-Cookie;
+    fastcgi_pass_header Cookie;
+    fastcgi_ignore_headers Cache-Control Expires Set-Cookie;
+    fastcgi_param SCRIPT_FILENAME /srv/www/mydomain.com/public_html$fastcgi_script_name;
+  }
+}
+```
+
+## Apache config
+@todo
+
+
+## WRK HTTP benchmarks
+#### Boost with nginx config
+Running 30s test @ http://testsite.dev/testpage <br>
+12 threads and 100 connections
+
+| Thread Stats  | Avg           | Stdev   | Max      | +/- Stdev  |
+| ------------- | ------------- | ------  | -------- | ---------- |
+| Latency       | 38.12ms       | 64.66ms | 343.24ms | 82.64%     |
+| Req/Sec       | 1.68k         | 755.46  | 16.98k   | 69.10%     |
+
+595713 requests in 30.10s, 6.84GB read <br>
+Requests/sec: 19791.44 <br>
+Transfer/sec: 232.74MB
+
+#### Boost without nginx config
+Running 30s test @ http://testsite.dev/testpage <br>
+12 threads and 100 connections
+
+| Thread Stats  | Avg           | Stdev    | Max     | +/- Stdev |
+| ------------- | ------------- | -------- | ------- | --------- |
+| Latency       | 1.68s         | 212.61ms | 2.00s   | 93.69%    |
+| Req/Sec       | 9.01          | 7.65     | 60.00   | 68.12%    |
+
+1670 requests in 30.05s, 20.13MB read <br>
+Socket errors: connect 0, read 0, write 0, timeout 7<br>
+Requests/sec: 55.58 <br>
+Transfer/sec: 685.99KB
+
+#### No cache
+Running 30s test @ http://testsite.dev/testpage <br>
+12 threads and 100 connections
+
+| Thread Stats  | Avg           | Stdev   | Max     | +/- Stdev |
+| ------------- | ------------- | ------- | ------- | --------- |
+| Latency       | 0.00us        | 0.00us  | 0.00us  | -nan%     |
+| Req/Sec       | 6.37          | 8.09    | 40.00   | 86.45%    |
+
+236 requests in 30.05s, 2.85MB read <br>
+Socket errors: connect 0, read 0, write 0, timeout 236 <br>
+Requests/sec: 7.85 <br>
+Transfer/sec: 97.04KB
+
+
+## The going on's
+1. Page is requested for the first time and is built dynamically by PHP.
+2. Page is cached on the local file system; if accessed by an anonymous user.
+3. When the route is requested again the page is served from the file system.
+4. For this module to do anything worth while the apache or nginx config must be applied.
+
+
+## Roadmap
+1. Sub-module Boost crawler; implementing Guzzle.
+2. Generate file cache via batch function.
+3. Implement cron to invalidate and re-generate cache.
\ No newline at end of file

README.txt

-
-BOOST MODULE FOR DRUPAL 7.x
----------------------------
-
-CONTENTS OF THIS README
------------------------
-
-   * Description
-   * Requirements
-   * Installation
-   * Support
-   * Credits
-
-DESCRIPTION
------------
-
-This module provides static page caching for Drupal websites.
-
-It provides a significant performance increase as well as
-scalability for sites that receive mostly anonymous traffic.
-Web pages load very fast from the cache instead of waiting on
-PHP and Drupal to serve them from the database. If the page is
-not found in the cache, then the request is passed to Drupal.
-
-More information: http://drupal.org/project/boost
-
-For information on supported features (as well as those deprecated
-since 7.x-1.x), please read: https://drupal.org/node/1434362
-
-
-REQUIREMENTS
-------------
-
-Drupal's clean URLs MUST be enabled and working properly.
-
-
-INSTALLATION
-------------
-
-Handbook page: http://drupal.org/node/1459690
-
-1. Goto: [Administer > Configuration > Search and metadata > Clean URLs]
-   and ensure that Drupal's clean URLs are enabled and working correctly
-   on your site.
-
-2. Unzip and upload the module folder (as is) to the sites/all/modules
-   folder in your Drupal installation directory.
-
-3. Goto: [Administer > Configuration > Development > Performance] and disable
-   the Drupal core cache for anonymous users. Boost will not be able to
-   generate its cache if a page is already in the Drupal core cache.
-   This is the only core setting you must disable, others can be left enabled.
-
-4. Goto: [Administer > Configuration > System > Boost > Boost Settings]
-   and review the default settings.
-
-5. Goto: [Administer > Configuration > System > Boost > File System]
-   Make sure that the cache directory is writeable by the web server:
-   you may need to create the directory, and set the permissions.
-   Ideally, the cache directory should be owned by your user and be in
-   the group of your web server ("www-data" on Debian/Ubuntu), with a
-   unix permission of 0775 (read/write/exec owner, read/write/exec group,
-   read/exec others).
-
-6. Review the other default Boost settings.
-
-7. IMPORTANT - This step is easy and required for Boost to work!
-   Backup the original .htaccess file from your Drupal installation
-   directory for safe keeping.
-   Copy the custom generated htaccess rule from [Administer > Configuration
-     > System > Boost > .htaccess > .htaccess Generation] page and paste
-   the rules into the Drupal htaccess file as shown below.
-
-    # RewriteBase /
-    -------paste the rules right here--------
-    # Rewrite URLs of the form 'x' to the form 'index.php?q=x'.
-    # Pass all requests not referring directly to files in the filesystem to
-    # index.php. Clean URLs are handled in drupal_environment_initialize().
-    RewriteCond %{REQUEST_FILENAME} !-f
-    RewriteCond %{REQUEST_FILENAME} !-d
-    RewriteCond %{REQUEST_URI} !=/favicon.ico
-    RewriteRule ^ index.php [L]
-
-Note: If you get "400 Bad Request" responses from Apache server, make sure you have configured the RewriteBase. For example when using VirtualHost configurations it is necessary to define as:
-
-    RewriteBase /
-
-For more information, please read the handbook page:
-http://drupal.org/node/1459690
-
-
-SUPPORT
--------
-
-Project issue queue:
-http://drupal.org/project/issues/boost
-
-Please take the time to review other support issues before posting a new one.
-It can be hard to debug boost support issues without access to the server.
-Provide as much information as possible in order to reproduce the issue.
-
-Feel free to post install tips in the installation handbook page:
-https://drupal.org/node/1459690
-
-Paid support is possible by contacting the module maintainers via their
-user contact page (see below). We also accept donations, see:
-https://drupal.org/node/1434362 (support section).
-
-
-CREDITS
--------
-
-4.7 Originally developed by Arto Bendiken.
-5.x Port by Alexander I. Grafov, developed by Mike Carper.
-6.x Port by Ben Lavender.
-6.x Developed & Maintained by
-  Mike Carper https://drupal.org/user/282446
-  since 2012, minimal maintenance by Mathieu Lutfy
-7.x Port by Mike Carper
-7.x Developed & Maintained by
-  Mike Carper (mikeytown2) https://drupal.org/user/282446
-  Mathieu Lutfy (bgm) https://drupal.org/user/89461
-

boost.admin.debug.inc

-<?php
-
-/**
- * @file
- * Admin page callbacks for the boost module.
- */
-
-/**
- * Form builder; Configure boost settings.
- *
- * @ingroup forms
- * @see system_settings_form()
- */
-function boost_admin_debug_settings() {
-
-  $form['boost_message_debug'] = array(
-    '#type' => 'checkbox',
-    '#title' => t('Send debug info for each request to watchdog.'),
-    '#default_value' => variable_get('boost_message_debug', BOOST_MESSAGE_DEBUG),
-    '#description' => t('Only use for debugging purposes as this can fill up watchdog fairly quickly.'),
-  );
-
-  // reset htaccess on submit;
-  $form['#submit'][] = 'boost_form_submit_handler';
-  return system_settings_form($form);
-}

boost.admin.expiration.inc

-<?php
-
-/**
- * @file
- * Admin page callbacks for the boost module.
- */
-
-/**
- * Form builder; Configure boost settings.
- *
- * @ingroup forms
- * @see system_settings_form()
- */
-function boost_admin_expiration_settings() {
-
-  $form['boost_ignore_flush'] = array(
-    '#type' => 'checkbox',
-    '#title' => t('Ignore a cache flush command if cron issued the request.'),
-    '#default_value' => variable_get('boost_ignore_flush', BOOST_IGNORE_FLUSH),
-    '#description' => t('Drupal will flush all caches when cron is executed, depending on the <a href="!urlcore">core minimum cache lifetime</a> setting. To ignore the request to flush the cache on cron runs, enable this option. If enabled, pages in the Boost cache will be flushed only when their <a href="!urlboost">Boost maximum cache lifetime</a> expires.',
-      array(
-        '!urlcore'  => url('admin/config/development/performance'),
-        '!urlboost' => url('admin/config/system/boost'),
-      )),
-  );
-  $form['boost_expire_cron'] = array(
-    '#type' => 'checkbox',
-    '#title' => t('Remove old cache files on cron.'),
-    '#default_value' => variable_get('boost_expire_cron', BOOST_EXPIRE_CRON),
-    '#description' => t('If enabled, each time cron runs Boost will check each cached page and delete those that have expired (maximum cache lifetime). The expiration time is displayed in the comment that Boost adds to the bottom of the html pages it creates. This setting is recommended for most sites.'),
-  );
-
-  // reset htaccess on submit;
-  $form['#submit'][] = 'boost_form_submit_handler';
-  return system_settings_form($form);
-}

boost.admin.filesystem.inc

-<?php
-
-/**
- * @file
- * Admin page callbacks for the boost module.
- */
-
-/**
- * Form builder; Configure boost settings.
- *
- * @ingroup forms
- * @see system_settings_form()
- */
-function boost_admin_filesystem_settings() {
-
-  $form['boost_root_cache_dir'] = array(
-    '#type' => 'textfield',
-    '#title' => t('Root cache directory'),
-    '#default_value' => variable_get('boost_root_cache_dir', BOOST_ROOT_CACHE_DIR),
-  );
-  $form['boost_normal_dir'] = array(
-    '#type' => 'textfield',
-    '#title' => t('Normal cache directory'),
-    '#default_value' => variable_get('boost_normal_dir', BOOST_NORMAL_DIR),
-  );
-  $form['boost_char'] = array(
-    '#type' => 'textfield',
-    '#title' => t('Character replacement for "?" in the URL'),
-    '#default_value' => variable_get('boost_char', BOOST_CHAR),
-  );
-
-  // reset htaccess on submit;
-  $form['#submit'][] = 'boost_form_submit_handler';
-  return system_settings_form($form);
-}

boost.admin.htaccess.inc

-<?php
-
-/**
- * @file
- * Admin page callbacks for the boost module.
- */
-
-/**
- * Default apache server name.
- */
-define('BOOST_SERVER_NAME_HTTP_HOST', '%{HTTP_HOST}');
-
-/**
- * Default apache document root.
- */
-define('BOOST_DOCUMENT_ROOT', '%{DOCUMENT_ROOT}');
-
-/**
- * Default setting for SSL pages
- */
-define('BOOST_SSL_BYPASS', TRUE);
-
-
-/**
- * Form builder; Configure boost settings.
- *
- * @ingroup forms
- * @see system_settings_form()
- */
-function boost_admin_htaccess_settings() {
-  global $base_path;
-
-  // Apache .htaccess settings generation
-//   $htaccess = boost_admin_generate_htaccess();
-  $form['htaccess'] = array(
-    '#type'          => 'fieldset',
-    '#title'         => t('Boost Apache .htaccess settings generation'),
-    '#description'   => t('<a href="!link">Explanation of .htaccess variables</a> <br /><br />  <em>Be sure to save the configuration and then go to the <a href="!rules">htaccess rules generation page</a> and copy the rules.</em> <br /><strong>Apache 2.4 users should uncomment the two marked sections, each line beginning with #</strong> ', array('!link' => url('http://www.askapache.com/htaccess/mod_rewrite-variables-cheatsheet.html'), '!rules' => url('admin/config/system/boost/htaccess/generator'))),
-  );
-  $form['htaccess']['boost_server_name_http_host'] = array(
-    '#type'          => 'radios',
-    '#title'         => t("Server's URL or Name"),
-    '#default_value' => variable_get('boost_server_name_http_host', BOOST_SERVER_NAME_HTTP_HOST),
-    '#options'       => array(
-      '%{HTTP_HOST}' => '%{HTTP_HOST}',
-      '%{SERVER_NAME}' => '%{SERVER_NAME}',
-      $_SERVER['HTTP_HOST'] => $_SERVER['HTTP_HOST'],
-      $_SERVER['SERVER_NAME'] => $_SERVER['SERVER_NAME'],
-    ),
-    '#description'   => t('Best to leave these as %{}, only try the last option(s) if boost is still not working.'),
-  );
-  // Set DOCUMENT_ROOT
-  $drupal_subdir = rtrim($base_path, '/');
-  $document_root = str_replace("\\", '/', getcwd()); // fix windows dir slashes
-  $document_root = trim(str_replace($drupal_subdir, '', $document_root)); // remove subdir
-  $options = array('%{DOCUMENT_ROOT}' => '%{DOCUMENT_ROOT}', $document_root => $document_root); // initial options
-  $rejects = array('SCRIPT_FILENAME', 'DOCUMENT_ROOT'); // values to ignore
-  $output = boost_admin_htaccess_array_find($document_root, $_SERVER, $rejects); //search for values that match getcwd
-  $description_extra = '';
-  if (!empty($output)) {
-    foreach ($output as $key => $value) {
-      $temp = '%{ENV:' . $key . '}';
-      $options[$temp] = $temp . ' = ' . $value; // adding values to options
-      if (strcmp($value, $document_root) == 0) {
-        $best = $temp; // set best since it's a match
-      }
-    }
-  }
-  if (strcmp($_SERVER['DOCUMENT_ROOT'], $document_root) == 0) {
-    $best = '%{DOCUMENT_ROOT}';
-  }
-  elseif (!isset($best)) {
-    $best = $document_root;
-    $description_extra = t('Please <a href="!link">open an boost issue on Drupal.org</a>, since apache and php might not be configured correctly.', array('!link' => url('http://drupal.org/node/add/project-issue/boost')));
-  }
-  $percent = 0;
-  $int = similar_text(substr(trim($_SERVER['DOCUMENT_ROOT']), 18, 1), substr(trim($document_root), 18, 1), $percent);
-  $description = t('Value of %best is recommended for this server.', array('%best' => $best)) . ' ' . $description_extra;
-  $form['htaccess']['boost_document_root'] = array(
-    '#type'          => 'radios',
-    '#title'         => t('Document Root'),
-    '#default_value' => variable_get('boost_document_root', BOOST_DOCUMENT_ROOT),
-    '#options'       => $options,
-    '#description'   => $description,
-  );
-  $form['htaccess']['boost_apache_etag'] = array(
-    '#type'          => 'radios',
-    '#title'         => t('ETag Settings'),
-    '#default_value' => variable_get('boost_apache_etag', BOOST_APACHE_ETAG),
-    '#options'       => array(
-      3 => "Set FileETag 'MTime Size' - Useful in server clusters (Highly Recommended)",
-      2 => "Set FileETag 'All' - Default if enabled",
-      1 => "Set FileETag 'None' - Do not send an etag",
-      0 => 'Do Nothing',
-    ),
-    '#description'   => t('Uses <a href="!link">FileETag Directive</a> to set <a href="!about">ETags</a> for the files cached by Boost. <a href="!stack">More info on this subject</a>', array('!link' => url('http://httpd.apache.org/docs/trunk/mod/core.html#fileetag'), '!about' => url('http://en.wikipedia.org/wiki/HTTP_ETag'), '!stack' => url('http://stackoverflow.com/questions/tagged?tagnames=etag&sort=votes&pagesize=50'))),
-  );
-  $form['htaccess']['boost_apache_xheader'] = array(
-    '#type'          => 'radios',
-    '#title'         => t('Boost Tags'),
-    '#default_value' => variable_get('boost_apache_xheader', BOOST_APACHE_XHEADER),
-    '#options'       => array(
-      1 => 'Set Boost header',
-      0 => 'Do not set Boost header',
-    ),
-    '#description'   => t('In order to identify that the page is being served from the cache, Boost can send out a header that will identify any files served from the boost cache.'),
-  );
-  $form['htaccess']['boost_ssl_bypass'] = array(
-    '#type'          => 'checkbox',
-    '#title'         => t('Bypass the boost cache for ssl requests.'),
-    '#default_value' => variable_get('boost_ssl_bypass', BOOST_SSL_BYPASS),
-    '#description'   => t('Ticking this is recommended if you use the securepages module.'),
-  );
-  $form['htaccess']['boost_add_default_charset'] = array(
-    '#type'          => 'checkbox',
-    '#title'         => t('Add "AddDefaultCharset X" to the htaccess rules'),
-    '#default_value' => variable_get('boost_add_default_charset', BOOST_ADD_DEFAULT_CHARSET),
-    '#description'   => t('Depending on your i18n settings you might want this disabled or enabled. X is set below'),
-  );
-  $form['htaccess']['boost_charset_type'] = array(
-    '#type'          => 'textfield',
-    '#title'         => t('Add "AddDefaultCharset utf-8" to the htaccess rules'),
-    '#default_value' => variable_get('boost_charset_type', BOOST_CHARSET_TYPE),
-    '#description'   => t('Depending on your i18n settings you might want this disabled or enabled.'),
-  );
-  $form['htaccess']['boost_match_symlinks_options'] = array(
-    '#type'          => 'radios',
-    '#title'         => t('%cache_folder Options', array( '%cache_folder' => $document_root . '/' . variable_get('boost_root_cache_dir', BOOST_ROOT_CACHE_DIR) . '/' . variable_get('boost_normal_dir', BOOST_NORMAL_DIR) . '/' . variable_get('boost_server_name_http_host', BOOST_SERVER_NAME_HTTP_HOST) . '/.htaccess' )),
-    '#default_value' => variable_get('boost_match_symlinks_options', BOOST_MATCH_SYMLINKS_OPTIONS),
-    '#options'       => array(
-      1 => 'Set "Options +FollowSymLinks"',
-      0 => 'Set "Options +SymLinksIfOwnerMatch"',
-    ),
-    '#description'   => t('The .htaccess file in the cache folder requires "Options +FollowSymLinks" or "Options +SymLinksIfOwnerMatch" for mod_rewrite. Some hosting companies only permit the SymLinksIfOwnerMatch option. If you get a http 500 error code try setting SymLinksIfOwnerMatch.'),
-  );
-
-  // reset htaccess on submit;
-  $form['#submit'][] = 'boost_form_submit_handler';
-  return system_settings_form($form);
-}
-
-/**
- * Form builder; Configure boost settings.
- *
- * @ingroup forms
- * @see system_settings_form()
- */
-function boost_admin_htaccess_generation() {
-  // Generated .htaccess output
-  $htaccess = boost_admin_htaccess_generate_htaccess();
-  $form['boost_generated'] = array(
-    '#type'          => 'textarea',
-    '#title'         => t('Generated Rules'),
-    '#default_value' => $htaccess,
-    '#rows'          => count(explode("\n", $htaccess))+1,
-    '#wysiwyg'       => FALSE,
-    '#description'   => t("Copy this into your .htaccess file below <pre><tt>  # If your site is running in a VirtualDocumentRoot at http://example.com/,
-  # uncomment the following line:
-  # RewriteBase / </tt></pre> and above <pre><tt>  # Pass all requests not referring directly to files in the filesystem to
-  # index.php. Clean URLs are handled in drupal_environment_initialize().</tt></pre><br />Note that the generated rules' settings can be configure at !link.", array('!link' => l('admin/config/development/performance/boost/htaccess-settings', 'admin/config/development/performance/boost/htaccess-settings'))),
-  );
-
-  // reset htaccess on submit;
-  $form['#submit'][] = 'boost_form_submit_handler';
-  return $form;
-}
-
-/**
- * Generate htaccess code.
- *
- * http://www.askapache.com/htaccess/mod_rewrite-variables-cheatsheet.html
- *
- * @return string
- *   htaccess code
- */
-function boost_admin_htaccess_generate_htaccess() {
-  global $base_path;
-  $server_name = variable_get('boost_server_name_http_host', BOOST_SERVER_NAME_HTTP_HOST);
-  $document_root = variable_get('boost_document_root', BOOST_DOCUMENT_ROOT);
-  $drupal_subdir = rtrim($base_path, '/');
-
-  // Various dir's
-  $cache_dir = variable_get('boost_root_cache_dir', BOOST_ROOT_CACHE_DIR);
-  $normal_dir = variable_get('boost_normal_dir', BOOST_NORMAL_DIR);
-  $char = variable_get('boost_char', BOOST_CHAR);
-
-  // Go through every storage type getting the extesion and if it supports gzip.
-  $enabled_file_extensions = array();
-  $types = boost_get_storage_types();
-  foreach ($types as $title => $content_types) {
-    foreach ($content_types as $type => $values) {
-      if ($values['enabled']) {
-        $enabled_file_extensions[$values['extension']]['gzip'] = $values['gzip'];
-        if (empty($enabled_file_extensions[$values['extension']]['content_type'])) {
-          $enabled_file_extensions[$values['extension']]['content_type'] = $type;
-        }
-      }
-    }
-  }
-
-  $output = array('gzip' => '', 'normal' => '');
-  $gzip_count = 0;
-  $normal_count = 0;
-  foreach ($enabled_file_extensions as $extension => $values) {
-    $type = $values['content_type'];
-    $output['normal'] .= "  RewriteCond $document_root$base_path$cache_dir/%{ENV:boostpath}/$server_name%{REQUEST_URI}$char%{QUERY_STRING}\.$extension -s\n";
-    $output['normal'] .= "  RewriteRule .* $cache_dir/%{ENV:boostpath}/$server_name%{REQUEST_URI}$char%{QUERY_STRING}\.$extension [L,T=$type]\n";
-    $normal_count++;
-  }
-  $skip = !empty($gzip_count) ? $normal_count + $gzip_count + 1 : $normal_count + 1;
-   
-
-  // Generate the rules
-  $string  = "  ### BOOST START ###\n";
-
-  if (!empty($output)) {
-    $string .= "\n";
-    $string .= "  # Allow for alt paths to be set via htaccess rules; allows for cached variants (future mobile support)\n";
-    $string .= "  RewriteRule .* - [E=boostpath:$normal_dir]\n";
-    $string .= "\n";
-
-    $string .= "#  # Apache 2.4 bug workaround\n";
-    $string .= "#  # Enables Search from home page https://drupal.org/node/2078595#comment-8724321\n";
-    $string .= "#  RewriteCond %{REQUEST_METHOD} ^(POST)$\n";
-    $string .= "#  RewriteCond %{REQUEST_URI} $base_path\n";
-    $string .= "#  RewriteRule .* $base_path [S=" . ($skip+1) . "]\n";
-    $string .= "\n";
-
-    $string .= "  # Caching for anonymous users\n";
-    $string .= "  # Skip boost IF not get request OR uri has wrong dir OR cookie is set OR request came from this server" . (variable_get('boost_ssl_bypass', BOOST_SSL_BYPASS) ? " OR https request" : "") . "\n";
-    $string .= "  RewriteCond %{REQUEST_METHOD} !^(GET|HEAD)$ [OR]\n";
-    $string .= "  RewriteCond %{REQUEST_URI} (^$base_path(admin|$cache_dir|misc|modules|sites|system|openid|themes|node/add|comment/reply))|(/(edit|user|user/(login|password|register))$) [OR]\n";
-    if (variable_get('boost_ssl_bypass', BOOST_SSL_BYPASS)) {
-      $string .= "  RewriteCond %{HTTPS} on [OR]\n";
-    }
-    $string .= "  RewriteCond %{HTTP_COOKIE} " . variable_get('boost_cookie', BOOST_COOKIE) . " [OR]\n";
-    $string .= "  RewriteCond %{ENV:REDIRECT_STATUS} 200\n";
-    $string .= "  RewriteRule .* - [S=$skip]\n";
-    $string .= "\n";
-
-    $string .= "#  # Apache 2.4 bug workaround\n";
-    $string .= "#  # Enables caching of index/ home page\n";
-    $string .= "#  RewriteCond %{REQUEST_URI} ^" . "$base_path" . "index\.php$\n";
-    $string .= "#  RewriteCond $document_root$base_path$cache_dir/%{ENV:boostpath}/%{HTTP_HOST}" . $base_path . "\\" . $char . "%{QUERY_STRING}\.html -s\n";
-
-    $string .= "#  RewriteRule .* $cache_dir/%{ENV:boostpath}/$server_name$base_path" . "\\" . $char ."%{QUERY_STRING}\.html [L,T=text/html]";
-    $string .= "\n";
-    $string .= "\n";
-
-    $string .= "  # NORMAL\n";
-    $string .= $output['normal'];
-  }
-  $string .= "\n";
-  $string .= "  ### BOOST END ###\n";
-
-  return $string;
-}
-
-/**
- * Returns all key/values in array that are equal.
- *
- * @param $needle
- *  What your searching for
- * @param $haystack
- *  Array of values
- * @param $a_not
- *  Optional array of key names to exclude
- */
-function boost_admin_htaccess_array_find($needle, $haystack, $a_not = array()) {
-  $out = array();
-  foreach ($haystack as $key => $value) {
-    if (is_string($value) && strstr($value, $needle) !== FALSE) {
-      $good = TRUE;
-      foreach ($a_not as $not) {
-        if (strpos($key, $not) !== FALSE) {
-          $good = FALSE;
-        }
-      }
-      if ($good) {
-        $out[$key] = $value;
-      }
-    }
-  }
-  return $out;
-}
-

boost.admin.inc

-<?php
-
-/**
- * @file
- * Admin page callbacks for the boost module.
- */
-
-/**
- * Form builder; Configure boost settings.
- *
- * @ingroup forms
- * @see system_settings_form()
- */
-function boost_admin_settings() {
-  drupal_add_js(drupal_get_path('module', 'system') . '/system.js');
-
-  $form['cacheability'] = array(
-    '#type'          => 'fieldset',
-    '#title'         => t('Boost cacheability settings'),
-  );
-  // See http://api.drupal.org/api/function/block_admin_configure/7
-  $access = user_access('use PHP for settings');
-  $options = array(
-    BOOST_VISIBILITY_NOTLISTED => t('All pages except those listed'),
-    BOOST_VISIBILITY_LISTED => t('Only the listed pages'),
-  );
-  $description = t("Specify pages by using their paths. Enter one path per line. The '*' character is a wildcard. Example paths are %blog for the blog page and %blog-wildcard for every personal blog. %front is the front page.", array('%blog' => 'blog', '%blog-wildcard' => 'blog/*', '%front' => '<front>'));
-  if (module_exists('php') && $access) {
-    $options += array(BOOST_VISIBILITY_PHP => t('Pages on which this PHP code returns <code>TRUE</code> (experts only)'));
-    $title = t('Pages or PHP code');
-    $description .= ' ' . t('If the PHP option is chosen, enter PHP code between %php. Note that executing incorrect PHP code can break your Drupal site.', array('%php' => '<?php ?>'));
-  }
-  else {
-    $title = t('Pages');
-  }
-  $form['cacheability']['boost_cacheability_option'] = array(
-    '#type' => 'radios',
-    '#title' => t('Cache specific pages'),
-    '#options' => $options,
-    '#default_value' => variable_get('boost_cacheability_option', BOOST_VISIBILITY_NOTLISTED),
-  );
-  $form['cacheability']['boost_cacheability_pages'] = array(
-    '#type' => 'textarea',
-    '#title' => '<span class="element-invisible">' . $title . '</span>',
-    '#default_value' => variable_get('boost_cacheability_pages', BOOST_CACHEABILITY_PAGES),
-    '#description' => $description,
-  );
-
-
-  $types = boost_get_storage_types();
-  $period = drupal_map_assoc(array(0, 60, 180, 300, 600, 900, 1800, 2700, 3600, 10800, 21600, 32400, 43200, 64800, 86400, 2*86400, 3*86400, 4*86400, 5*86400, 6*86400, 604800, 2*604800, 3*604800, 4*604800, 8*604800, 16*604800, 52*604800), 'format_interval');
-
-  $form['cache_types'] = array(
-    '#type'          => 'fieldset',
-    '#title'         => t('Boost cache type settings'),
-  );
-  foreach ($types as $title => $content_types) {
-    $form['cache_types'][$title] = array(
-      '#type'          => 'fieldset',
-      '#title'         => t('@title settings', array('@title' => $title)),
-      '#collapsible' => TRUE,
-    );
-    $collapsed = TRUE;
-    foreach ($content_types as $type => $values) {
-      $form['cache_types'][$title][$type] = array(
-        '#type'           => 'fieldset',
-        '#title'          => t('@type settings', array('@type' => $type)),
-        '#description'    => t('Cache @description of type @type',
-          array(
-            '@description' => $values['description'],
-            '@type' => $type,
-          )
-        ),
-      );
-      // This content type enabled?
-      $form['cache_types'][$title][$type]['boost_enabled_' . $type] = array(
-        '#type'          => 'checkbox',
-        '#title'         => t('Cache Enabled'),
-        '#default_value' => $values['enabled'],
-      );
-// https://drupal.org/node/1416214#comment-7225650
-//      // Enable gzip?
-//      $form['cache_types'][$title][$type]['boost_gzip_' . $type] = array(
-//        '#type'          => 'checkbox',
-//        '#title'         => t('Enable gzip compression'),
-//        '#description'   => (BOOST_GZIP ? t('Avoids having to compress the content by the web server on every request (recommended).') : t('Your host does not support zlib. See: !url', array('!url' => 'http://www.php.net/manual/en/zlib.installation.php'))),
-//        '#default_value' => (BOOST_GZIP ? $values['gzip'] : 0),
-//        '#disabled'      => ! BOOST_GZIP,
-//      );
-
-      // Content type extension
-      $form['cache_types'][$title][$type]['boost_extension_' . $type] = array(
-        '#type'          => 'textfield',
-        '#title'         => t('Filename Extension',
-          array(
-            '@title' => $title,
-            '@description' => $values['description'],
-            '@type' => $type,
-          )
-        ),
-        '#default_value' => $values['extension'],
-      );
-
-      // Maximum cache lifetime
-      $form['cache_types'][$title][$type]['boost_lifetime_max_' . $type] = array(
-        '#type'          => 'select',
-        '#options' => $period,
-        '#title'         => t('@type - Maximum Cache Lifetime',
-          array(
-            '@title' => $title,
-            '@description' => $values['description'],
-            '@type' => $type,
-          )
-        ),
-        '#default_value' => $values['lifetime_max'],
-      );
-
-      // Minimum cache lifetime
-      $form['cache_types'][$title][$type]['boost_lifetime_min_' . $type] = array(
-        '#type'          => 'select',
-        '#options' => $period,
-        '#title'         => t('@type - Minimum Cache Lifetime',
-          array(
-            '@title' => $title,
-            '@description' => $values['description'],
-            '@type' => $type,
-          )
-        ),
-        '#default_value' => $values['lifetime_min'],
-      );
-      if ($values['enabled']) {
-        $collapsed = !$values['enabled'];
-      }
-    }
-    $form['cache_types'][$title]['#collapsed'] = $collapsed;
-  }
-
-  // reset htaccess on submit;
-  $form['#submit'][] = 'boost_form_submit_handler';
-  return system_settings_form($form);
-}

boost.admin.modules.inc

-<?php
-
-/**
- * @file
- * Displays compatible modules for boost, descriptions of functionality and
- * links if not installed.
- */
-
-/**
- * Returns a table listing of the status of recommended modules.
- */
-function boost_compatible_output() {
-  $modules_enabled = array();
-  $modules_disabled = array();
-
-  // Query from the database in case modules are already installed but not enabled
-  $result = db_query("SELECT name, status FROM {system} WHERE type = 'module' ORDER BY weight ASC, name ASC");
-  foreach ($result as $record) {
-    if ($record->status == 1) {
-      $modules_enabled[] = $record->name;
-    }
-    else {
-      $modules_disabled[] = $record->name;
-    }
-  }
-
-  // list of compatible modules
-  $recommended = array(
-    'boost_crawler' => array(
-      'title' => 'Boost Crawler',
-      'link' => 'http://drupal.org/project/boost' ,
-      'description' => t('Minimal crawler - expires and regenerates pages only when content is edited and on next cron run. If this module is disabled, the content will be regenerated by the next visitor (who may have a slow page load). Only recommended for sites with low traffic, since the page cache will probably have been regenerated by the time the crawler accesses it. This is a Boost sub-module.'),
-    ),
-    'fast_404' => array(
-      'title' => 'Fast 404',
-      'link' => 'http://drupal.org/project/fast_404' ,
-      'description' => t('Produces a faster "page not found" (404) page, reducing server load. Boost does not cache 404 pages since it would increase the size of the cache for pages which should not be accessed anyway. However, the default 404 mechanism of Drupal can be expensive in terms of performance. If you have a large amount of 404, consider adding a redirection for them in your .htaccess file.'),
-    ),
-    'globalredirect' => array(
-      'title' => 'Global Redirect',
-      'link' => 'http://drupal.org/project/globalredirect',
-      'description' => t('Redirects pages to their canonical URL. Avoids caching two pages for the same content.'),
-    ),
-    'httprl' => array(
-      'title' => 'HTTP Parallel Request & Threading Library',
-      'link' =>  'http://drupal.org/project/httprl',
-      'description' => t('Required by Boost crawler, performs HTTP requests to regenerate expired pages.'),
-    ),
-    'expire' => array(
-      'title' => 'Cache Expiration',
-      'link' => 'http://drupal.org/project/expire',
-      'description' => t('Expire specific pages of the cache immediately when content is added or modified. Also required by the Boost crawler, to crawl expired content after expiration.'),
-    ),
-  );
-
-  ksort($recommended);
-
-  // uses array_intersect as array_intersect_key only came in PHP > 5.1
-  $installed = array_intersect($modules_enabled, array_keys($recommended));
-  $disabled = array_intersect($modules_disabled, array_keys($recommended));
-  $not_installed = array_diff( array_diff( array_keys($recommended), $installed), $disabled );
-
-  // prepare the table
-  $header = array(t('Module'), t('Status'), t('Description'));
-
-  $rows = array();
-
-  foreach ($recommended as $module => $data) {
-    $status = in_array($module, $not_installed) ? t('Not Installed') : (in_array($module, $disabled) ? t('Disabled') : t('Enabled'));
-    $trclass = in_array($module, $not_installed) ? 'info' : (in_array($module, $disabled) ? 'warning' : 'ok' ) ;
-    $module_link = l($data['title'], $data['link']);
-
-    $rows[] = array(
-      'data' => array(
-        $module_link,
-        $status,
-        $data['description'],
-      ),
-      'class' => array($trclass),
-      'no_striping' => TRUE,
-    );
-  }
-
-  $output = '<p class="boost-listmodules-intro">' . t("The following modules can be useful for most common use cases. For more information, please read and contribute to the <a href='!url'>Boost handbook</a>.", array('!url' => 'http://drupal.org/node/1434362')) . '</p>';
-
-  $output .= theme('table', array('attributes' => array('class' => array('system-status-report')), 'header' => $header, 'rows' => $rows));
-
-  return array(
-   'my_page' => array(
-      '#markup' => $output,
-    ),
-  );
-}
-

boost.blocks.inc

-<?php
-
-/**
- * @file
- * Prints the cache status of the currently displayed page.
- *
- * see @boost_block_view()
- */
-function boost_block_view_status() {
-  global $user;
-
-  $block = array();
-  $block['subject'] = '';
-
-  // Don't show the block to anonymous users
-  if (! $user->uid) {
-    return $block;
-  }
-
-  // Do not use the global $_boost to not confuse hook_exit()
-  $_boost = boost_transform_url();
-
-  // Unset these variables otherwise boost_is_cacheable() will quickly bail out.
-  unset($_boost['is_cacheable']);
-  unset($_boost['is_cacheable_reason']);
-
-  $_boost = boost_is_cacheable($_boost, 'status');
-
-  if (! $_boost['is_cacheable']) {
-    $reason = ($_boost['is_cacheable_reason'] ? $_boost['is_cacheable_reason'] : 'reason unknown');
-    $block['content']['is_not_cacheable'] = array(
-      '#markup' => '<p>' . t('This page will not be cached: %reason', array('%reason' => $reason)) . '</p>',
-    );
-
-    return $block;
-  }
-
-  // We need the extention for the filename
-  $_boost['header_info'] = boost_get_header_info();
-  $_boost['matched_header_info'] = boost_match_header_attributes($_boost['header_info']);
-
-  $filename = (isset($_boost['filename']) ? $_boost['filename'] . '.' . $_boost['matched_header_info']['extension'] : 'n/a');
-
-  if (file_exists($filename)) {
-    // be precise on the time (seconds and timezone)
-    $generated = date('c', filemtime($filename));
-  }
-  else {
-    $generated = 'not cached yet (either no one has visited the page recently, or something is preventing the cache from being generated).';
-  }
-
-  $block['content'] = array(
-    'filename' => array(
-      '#markup' => '<p>' . t('File: %filename', array('%filename' => $filename)) . '</p>',
-    ),
-    'generated' => array(
-      '#markup' => '<p>' . t('Generated: %generated', array('%generated' => $generated)) . '</p>',
-    ),
-  );
-
-  if (file_exists($filename) && user_access('boost flush pages')) {
-    // 1922532 - Variable required to remove warning under PHP 5.4
-    $form = drupal_get_form('boost_block_flush_form');
-    $block['content']['flush'] = array(
-      '#markup' => drupal_render($form),
-    );
-  }
-
-  return $block;
-}
-
-function boost_block_flush_form() {
-  $form = array();
-
-  $form['boost_cache']['clear'] = array(
-    '#type' => 'submit',
-    '#value' => t('Flush Page'),
-  );
-
-  return $form;
-}
-
-function boost_block_flush_form_submit() {
-  $_boost = boost_transform_url();
-
-  // We need the extention for the filename
-  $_boost['header_info'] = boost_get_header_info();
-  $_boost['matched_header_info'] = boost_match_header_attributes($_boost['header_info']);
-
-  $filename = $_boost['filename'] . '.' . $_boost['matched_header_info']['extension'];
-
-  if (is_file($filename)) {
-    if (unlink($filename)) {
-      drupal_set_message(t('%filename was deleted from the Boost cache', array('%filename' => $filename)));
-    }
-    else {
-      drupal_set_message(t('%filename could not be deleted, check file permissions on disk to see if the web server can write/delete the file.', array('%filename' => $filename)));
-    }
-  }
-  else {
-    drupal_set_message(t('%filename was not found in the Boost cache and could not be deleted.', array('%filename' => $filename)));
-  }
-}
-

boost.drush.inc

-<?php
-
-/**
- * @file
- * Drush commands for Boost.
- */
-
-/**
- * Implements hook_drush_cache_clear.
- */
-function boost_drush_cache_clear(&$types) {
-  $types['boost'] = 'boost_drush_cache_clear_all';
-}
-
-/**
- * Clears all Boost cached data.
- */
-function boost_drush_cache_clear_all() {
-  $ignore = variable_get('boost_ignore_flush', 0);
-  $GLOBALS['conf']['boost_ignore_flush'] = 0;
-
-  boost_flush_caches();
-
-  $GLOBALS['conf']['boost_ignore_flush'] = $ignore;
-}

boost.info

-name = Boost
-description = Caches generated output as a static file to be served directly from the webserver.
-package = Performance and scalability
-core = 7.x
-files[] = boost.module
-files[] = boost.admin.inc
-files[] = boost.blocks.inc
-recommends[] = expire
-configure = admin/config/system/boost

boost.info.yml

+name: Boost
+type: module
+description: Provides boost caching mechanism integration
+core: 8.x
+package: Boost

boost.install

-<?php
-
-/**
- * @file
- * Handles Boost module installation and upgrade tasks.
- */
-
-//////////////////////////////////////////////////////////////////////////////
-// Core API hooks
-
-/**
- * Implements hook_enable().
- */
-function boost_enable() {
-  boost_htaccess_cache_dir_put();
-}
-
-/**
- * Implements hook_disable().
- */
-function boost_disable() {
-  // Make sure that the static page cache is wiped when the module is disabled:
-  boost_flush_caches();
-  drupal_set_message(t('Static page cache cleared.'));
-}
-
-/**
- * Implements hook_install().
- */
-function boost_install() {
-}
-
-/**
- * Implements hook_uninstall().
- */
-function boost_uninstall() {
-  // Clear variables
-  $name = 'boost_';
-  db_delete('variable')
-    ->condition('name', db_like($name) . '%', 'LIKE')
-    ->execute();
-  cache_clear_all('variables', 'cache_bootstrap');
-}
-
-/**
- * Implements hook_requirements().
- */
-function boost_requirements($phase) {
-  $requirements = array();
-  $t = get_t();
-  // Check the server's ability to use boost
-  if ($phase == 'runtime') {
-    // Check if core cache is enabled
-    $core_cache = variable_get('cache', 0);
-    if ($core_cache) {
-      $requirements['boost_core_cache'] = array(
-        'title' => $t('Boost'),
-        'value' => $t('Core cache is enabled'),
-        'severity' => REQUIREMENT_WARNING,
-        'description' => $t('Boost will not function properly while Drupal core cache is enabled. Disable Boost or <a href="@settings">the core cache</a>.', array('@settings' => url('admin/config/development/performance'))),
-      );
-    }
-
-    // Check cache directories
-    $cache_directories = array(
-      boost_get_normal_cache_dir(),
-    );
-    foreach ($cache_directories as $cache_directory) {
-      if (boost_mkdir($cache_directory)) {
-//         $root_file = file_put_contents($cache_directory . '/' . variable_get('boost_root_file', '.boost'), $cache_directory);
-      }
-      if (!is_dir($cache_directory)) {
-        $requirements['boost_default'] = array(
-          'title'       => $t('Boost'),
-          'description' => $t('!cache_dir: does not exist.', array('!cache_dir' => $cache_directory)),
-          'severity'    => REQUIREMENT_ERROR,
-          'value'       => $t('Cache path'),
-        );
-      }
-      if (is_dir($cache_directory) && (!is_writable($cache_directory))) {
-        $requirements['boost_permissions'] = array(
-          'title'       => $t('Boost'),
-          'description' => $t('Directory %dir credentials - Permissions: %fp. Owner %fo. Group %fg.<br /> Your credentials - Group ID: %gid. User ID: %uid. Current script owner: %user.', array('%dir' => getcwd() . '/' . $cache_directory, '%gid' => getmygid(), '%uid' => getmyuid(), '%user' => get_current_user(), '%fp' => substr(sprintf('%o', fileperms($cache_directory)), -4), '%fo' => fileowner($cache_directory), '%fg' => filegroup($cache_directory) )),
-          'severity'    => REQUIREMENT_ERROR,
-          'value'       => $t('Can not write to file-system'),
-        );
-      }
-    }
-    if (empty($requirements)) {
-      $requirements['boost'] = array(
-        'title'       => $t('Boost'),
-        'severity'    => REQUIREMENT_OK,
-        'value'       => $t('Boost installed correctly, should be working if properly <a href="@settings">configured</a>.', array('@settings' => url('admin/config/system/boost'))),
-      );
-    }
-  }
-  return $requirements;
-}

boost.services.yml

+services:
+  boost.subscriber:
+    class: Drupal\boost\EventSubscriber\BoostResponseSubscriber
+    arguments: ['@html_response.attachments_processor', '@current_user']
+    tags:
+      - {name: event_subscriber}
+  boost.route:
+    class: Drupal\boost\BoostCacheRoute
+    arguments: ['@path.current', '@path.alias_manager']
\ No newline at end of file

boost_crawler/boost_crawler.admin.inc

-<?php
-
-/**
- * @file
- * Admin page callbacks for the boost_crawler module.
- */
-
-/**
- * Form builder; Configure boost_crawler settings.
- *
- * @ingroup forms
- * @see system_settings_form()
- */
-function boost_crawler_admin_settings() {
-  $form['boost_crawl_on_cron'] = array(
-    '#type' => 'checkbox',
-    '#title' => t('Enable the cron crawler'),
-    '#default_value' => variable_get('boost_crawl_on_cron', FALSE),
-    '#description'   => t("Pre-cache the pages of the website so they get cached before anyone accesses them."),
-  );
-
-  $form['boost_crawl_queue_seconds'] = array(
-    '#type' => 'textfield',
-    '#title' => t('Time (in seconds) to use for crawling on every cron run'),
-    '#default_value' => variable_get('boost_crawl_queue_seconds', 30),
-    '#description'   => t("If this it too long, it may cause problems with other tasks that run during the cron runs."),
-  );
-
-  return system_settings_form($form);
-}
-

boost_crawler/boost_crawler.info

-name = Boost Crawler
-description = Minimal crawler to regenerate the cache as pages are expired.
-package = Performance and scalability
-core = 7.x
-files[] = boost_crawler.module
-recommends[] = boost
-dependencies[] = httprl
-dependencies[] = expire
-configure = admin/config/system/boost/crawler

boost_crawler/boost_crawler.module

-<?php
-
-/**
- * @file
- * Minimal crawler to regenerate the cache as pages are expired.
- */
-
-/**
- * Implements hook_menu().
- */
-function boost_crawler_menu() {
-  $items = array();
-
-  $items['admin/config/system/boost/crawler'] = array(
-    'title' => 'Crawler',
-    'description' => 'Configuration for the Boost crawler.',
-    'page callback' => 'drupal_get_form',
-    'page arguments' => array('boost_crawler_admin_settings'),
-    'access arguments' => array('administer site configuration'),
-    'type' => MENU_LOCAL_TASK,
-    'file' => 'boost_crawler.admin.inc',
-  );
-
-  return $items;
-}
-
-/**
- * Implements hook_cron_queue_info()
- */
-function boost_crawler_cron_queue_info() {
-  $queues['boost_crawler'] = array(
-    'worker callback' => 'boost_crawler_run',
-    'time' => variable_get('boost_crawl_queue_seconds', 30), // max run time to claim per cron run (in seconds).
-  );
-
-  return $queues;
-}
-
-/**
- * Implements hook_expire_cache (from the 'expire' module)
- */
-function boost_crawler_expire_cache($urls) {
-  global $base_root;
-
-  if (variable_get('boost_crawl_on_cron', FALSE)) {
-    foreach ($urls as $url) {
-      // Put URLs in a queue for processing by cron
-      // http://drupal.org/node/1074080#comment-4590150
-      $queue = DrupalQueue::get('boost_crawler');
- 
-      // Check if the URL to be flushed matches our base URL
-      if (strpos($base_root, $url) == 0) {
-        $queue->createItem($url);
-      }
-    }
-  }
-}
-
-/**
- * Worker Callback for the boost_crawler cron queue.
- */
-function boost_crawler_run($url) {
-  // Not doing async requests in order not to kill the server
-  // and also for the 'time' limit of the queue to make sense.
-  $options = array(
-    'headers' => array(
-      'Pragma' => 'no-cache',
-    ),
-  );
-
-  httprl_request($url, $options);
-  $request = httprl_send_request();
-
-  boost_log('Crawler fetched !url', array('!url' => $url), WATCHDOG_DEBUG);
-}
-

src/BoostCache.php

+<?php
+
+/**
+ * @file
+ * Contains Drupal\boost\BoostCache
+ */
+
+namespace Drupal\boost;
+
+use Drupal\boost\BoostCacheRoute;
+use Drupal\boost\BoostCacheHandler;
+
+/**
+ * The BoostCache class.
+ *
+ * @todo, only fire notices if debug (mode) enabled.
+ * @todo, batch to generate entire cache.
+ * @todo, cron to re-generate/ invalidate cache.
+ * @todo, exclude route list, don't cache specific paths.
+ */
+class BoostCache {
+
+  /**
+   * @var \Drupal\boost\BoostCacheHandler
+   */
+  protected $handler;
+
+  /**
+   * @var \Drupal\boost\BoostCacheRoute
+   */
+  protected $route;
+
+  /**
+   * @var \Psr\Log\LoggerInterface
+   */
+  protected $logger;
+
+  /**
+   * Constructs a new BoostCache.
+   */
+  public function __construct() {
+    $this->handler = new BoostCacheHandler();
+    $this->route = new BoostCacheRoute(
+      \Drupal::service('path.current'), 
+      \Drupal::service('path.alias_manager')
+    );
+    $this->logger = \Drupal::logger('boost');
+  }
+
+  /**
+   * Save page to local filesystem.
+   * @param string $response
+   *
+   *  @todo, _toString if Symfony Response.
+   */
+  public function index($response) {
+    if (!is_string($response)) {
+      $this->logger->notice('Response for route @uri can not be cached.',
+        array(
+            '@uri' => $this->route->getPath()
+        )
+      );
+
+      return;
+    }
+
+    $this->handler->setCache($this->route->getUri(), $response);
+  }
+
+  /**
+   * Retrieve Boost cache file.
+   */
+  public function retrieve() {
+    $uri = $this->route->getUri();
+
+    if (!file_exists($uri)) {
+      $this->logger->notice('Route @uri not cached.',
+        array(
+            '@uri' => $uri
+        )
+      );
+
+      return false;
+    }
+
+    return $this->handler->getCache($uri);
+  }
+
+  /**
+   * Delete individual cache file.
+   */
+  public function delete() {
+    $uri = $this->route->getUri();
+
+    if (!file_exists($uri)) {
+      return false;
+    }
+
+    return $this->handler->deleteCache($uri);
+  }
+
+  /**
+   * Delete entire boost cache.
+   */
+  public function purge() {
+    
+  }
+
+}

src/BoostCacheFile.php

+<?php
+
+/**
+ * @file
+ * Contains Drupal\boost\BoostCacheFile
+ *
+ * @todo, managed files...
+ */
+
+namespace Drupal\boost;
+
+use Drupal\Core\File\FileSystem;
+
+/**
+ * BoostCacheFile class.
+ */
+class BoostCacheFile {
+
+  /**
+   * Default mode for new directories.
+   */
+  const CHMOD_DIRECTORY = 0775;
+
+  /**
+   * The file uri.
+   */
+  protected $uri;
+
+  /**
+   * @var \Drupal\Core\File\FileSystem
+   */
+  protected $filesystem;
+
+  /**
+   * @param \Drupal\Core\File\FileSystem $filesystem
+   *    Provides helpers to operate on files and stream wrappers.
+   */
+  public function __construct(FileSystem $filesystem) {
+    $this->filesystem = $filesystem;
+  }
+
+  /**
+   * Load file contents by uri.
+   * @param $uri string
+   */
+  public function load($uri) {
+    return file_get_contents($uri);  
+  }
+
+  /**
+   * Create new cache file.
+   * @param string $uri
+   * @param string $content
+   */
+  public function save($uri, $content) {
+    $this->directory($uri);
+    $this->modify($uri, $content);
+  }
+
+  /**
+   * Delete cache file by uri.
+   * @param string $uri
+   */
+  public function delete($uri) {
+    return $this->filesystem->unlink($uri);
+  }
+
+  /**
+   * Make directory.
+   * @param string $uri
+   */
+  private function directory($uri) {
+    $dir = $this->filesystem->dirname($uri);
+
+    if (!file_exists($dir)) {
+      $this->filesystem->mkdir($dir, static::CHMOD_DIRECTORY, TRUE);
+    }
+  }
+
+  /**
+   * Overrite existing cache file.
+   * @param string $uri
+   * @param string $content
+   */
+  private function modify($uri, $content) {
+    return file_unmanaged_save_data($content, $uri, FILE_EXISTS_REPLACE);
+  }
+
+}

[Carsten Logemann]

I forgot to add the real author: @swim (https://www.drupal.org/u/swim)