Download.php

<?php

namespace Drupal\migrate\Plugin\migrate\process;

use Drupal\Core\File\FileSystemInterface;
use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Drupal\migrate\MigrateException;
use Drupal\migrate\MigrateExecutableInterface;
use Drupal\migrate\Row;
use GuzzleHttp\Client;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Downloads a file from a HTTP(S) remote location into the local file system.
 *
 * The source value is an array of two values:
 * - source URL, e.g. 'http://www.example.com/img/foo.img'
 * - destination URI, e.g. 'public://images/foo.img'
 *
 * Available configuration keys:
 * - file_exists: (optional) Replace behavior when the destination file already
 *   exists:
 *   - 'replace' - (default) Replace the existing file.
 *   - 'rename' - Append _{incrementing number} until the filename is
 *     unique.
 *   - 'use existing' - Do nothing and return FALSE.
 * - guzzle_options: (optional)
 *   @link http://docs.guzzlephp.org/en/latest/request-options.html Array of request options for Guzzle. @endlink
 *
 * Examples:
 *
 * @code
 * process:
 *   plugin: download
 *   source:
 *     - source_url
 *     - destination_uri
 * @endcode
 *
 * This will download source_url to destination_uri.
 *
 * @code
 * process:
 *   plugin: download
 *   source:
 *     - source_url
 *     - destination_uri
 *   file_exists: rename
 * @endcode
 *
 * This will download source_url to destination_uri and ensure that the
 * destination URI is unique. If a file with the same name exists at the
 * destination, a numbered suffix like '_0' will be appended to make it unique.
 *
 * @MigrateProcessPlugin(
 *   id = "download"
 * )
 */
class Download extends FileProcessBase implements ContainerFactoryPluginInterface {
    
    /**
     * The file system service.
     *
     * @var \Drupal\Core\File\FileSystemInterface
     */
    protected $fileSystem;
    
    /**
     * The Guzzle HTTP Client service.
     *
     * @var \GuzzleHttp\Client
     */
    protected $httpClient;
    
    /**
     * Constructs a download process plugin.
     *
     * @param array $configuration
     *   The plugin configuration.
     * @param string $plugin_id
     *   The plugin ID.
     * @param mixed $plugin_definition
     *   The plugin definition.
     * @param \Drupal\Core\File\FileSystemInterface $file_system
     *   The file system service.
     * @param \GuzzleHttp\Client $http_client
     *   The HTTP client.
     */
    public function __construct(array $configuration, $plugin_id, array $plugin_definition, FileSystemInterface $file_system, Client $http_client) {
        $configuration += [
            'guzzle_options' => [],
        ];
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->fileSystem = $file_system;
        $this->httpClient = $http_client;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('file_system'), $container->get('http_client'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
        // If we're stubbing a file entity, return a uri of NULL so it will get
        // stubbed by the general process.
        if ($row->isStub()) {
            return NULL;
        }
        list($source, $destination) = $value;
        // Modify the destination filename if necessary.
        $final_destination = $this->fileSystem
            ->getDestinationFilename($destination, $this->configuration['file_exists']);
        // Reuse if file exists.
        if (!$final_destination) {
            return $destination;
        }
        // Try opening the file first, to avoid calling prepareDirectory()
        // unnecessarily. We're suppressing fopen() errors because we want to try
        // to prepare the directory before we give up and fail.
        $destination_stream = @fopen($final_destination, 'w');
        if (!$destination_stream) {
            // If fopen didn't work, make sure there's a writable directory in place.
            $dir = $this->fileSystem
                ->dirname($final_destination);
            if (!$this->fileSystem
                ->prepareDirectory($dir, FileSystemInterface::CREATE_DIRECTORY | FileSystemInterface::MODIFY_PERMISSIONS)) {
                throw new MigrateException("Could not create or write to directory '{$dir}'");
            }
            // Let's try that fopen again.
            $destination_stream = @fopen($final_destination, 'w');
            if (!$destination_stream) {
                throw new MigrateException("Could not write to file '{$final_destination}'");
            }
        }
        // Stream the request body directly to the final destination stream.
        $this->configuration['guzzle_options']['sink'] = $destination_stream;
        try {
            // Make the request. Guzzle throws an exception for anything but 200.
            $this->httpClient
                ->get($source, $this->configuration['guzzle_options']);
        } catch (\Exception $e) {
            throw new MigrateException("{$e->getMessage()} ({$source})");
        }
        return $final_destination;
    }

}