Added new drush command to install the libraries.

Closes #2445701

drush/owlcarousel.drush.inc

+<?php
+
+/**
+ * @file
+ * Drush integration for owlcarousel.
+ */
+
+use Symfony\Component\Filesystem\Filesystem;
+
+/**
+ * The Owlcarousel2 plugin URI.
+ */
+define('OWLCAROUSEL_DOWNLOAD_URI', 'https://github.com/OwlCarousel2/OwlCarousel2/archive/master.zip');
+define('OWLCAROUSEL_DOWNLOAD_PREFIX', 'owlcarousel-');
+
+/**
+ * Implements hook_drush_command().
+ */
+function owlcarousel_drush_command() {
+  $items = [];
+
+  // The key in the $items array is the name of the command.
+  $items['owlcarousel-plugin'] = [
+    'callback' => 'drush_owlcarousel_plugin',
+    'description' => dt('Download and install the OwlCarousel2 plugin.'),
+     // No bootstrap.
+    'bootstrap' => DRUSH_BOOTSTRAP_DRUSH,
+    'arguments' => [
+      'path' => dt('Optional. A path where to install the OwlCarousel2 plugin. If omitted Drush will use the default location.'),
+    ],
+    'aliases' => ['owlcarouselplugin'],
+  ];
+
+  return $items;
+}
+
+/**
+ * Implements hook_drush_help().
+ *
+ * This function is called whenever a drush user calls
+ * 'drush help <name-of-your-command>'
+ */
+function owlcarousel_drush_help($section) {
+  switch ($section) {
+    case 'drush:owlcarousel-plugin':
+      return dt('Download and install the Owlcarousel2 plugin from OwlCarousel2/OwlCarousel2, default location is the libraries directory.');
+  }
+}
+
+/**
+ * Command to download the Owlcarousel plugin.
+ */
+function drush_owlcarousel_plugin() {
+  $args = func_get_args();
+  if (!empty($args[0])) {
+    $path = $args[0];
+  }
+  else {
+    $path = 'libraries';
+  }
+
+  // Create the path if it does not exist.
+  if (!is_dir($path)) {
+    drush_op('mkdir', $path);
+    \Drupal::logger(dt('Directory @path was created', ['@path' => $path]))->notice('notice');
+  }
+
+  // Set the directory to the download location.
+  $olddir = getcwd();
+  chdir($path);
+
+  // Download the zip archive.
+  if ($filepath = drush_download_file(OWLCAROUSEL_DOWNLOAD_URI)) {
+    $filename = basename($filepath);
+    $dirname = OWLCAROUSEL_DOWNLOAD_PREFIX . basename($filepath, '.zip');
+
+    // Remove any existing Owlcarousel2 plugin directory.
+    if (is_dir($dirname) || is_dir('owlcarousel2')) {
+      Filesystem::remove($dirname, TRUE);
+      Filesystem::remove('owlcarousel2', TRUE);
+      \Drupal::logger(dt('A existing Owlcarousel2 plugin was deleted from @path', ['@path' => $path]))->notice('notice');
+    }
+
+    // Decompress the zip archive.
+    drush_tarball_extract($filename);
+
+    // Change the directory name to "owlcarousel2" if needed.
+    if ($dirname != 'owlcarousel2') {
+      drush_move_dir($dirname, 'owlcarousel2', TRUE);
+      $dirname = 'owlcarousel2';
+    }
+  }
+
+  if (is_dir($dirname)) {
+    \Drupal::logger(dt('Owlcarousel2 plugin has been installed in @path', ['@path' => $path]))->success('success');
+  }
+  else {
+    \Drupal::logger(dt('Drush was unable to install the Owlcarousel2 plugin to @path', ['@path' => $path]))->error('error');
+  }
+
+  // Set working directory back to the previous working directory.
+  chdir($olddir);
+}