LOOP-1158: Added custom mail system

Author: martinyde

web/profiles/custom/os2loop/modules/os2loop_mail_notifications/src/Plugin/Mail/PhpMail.php

@@ -0,0 +1,173 @@
+<?php
+
+namespace Drupal\os2loop_mail_notifications\Plugin\Mail;
+
+use Drupal\Core\Mail\MailInterface;
+use Drupal\Core\Site\Settings;
+use Symfony\Component\Mime\Header\Headers;
+use Symfony\Component\Mime\Header\UnstructuredHeader;
+
+/**
+ * Copy of the default Drupal mail backend, using PHP's native mail() function.
+ *
+ * The only thing changed is the namespace, id, format() method and
+ * $message['headers']['Content-Type'] in mail() method.
+ *
+ * @Mail(
+ *   id = "os2loop_mail_notifications",
+ *   label = @Translation("Custom PHP mailer"),
+ *   description = @Translation("Sends the message as plain text, using PHP's native mail() function.")
+ * )
+ */
+class PhpMail implements MailInterface {
+
+  /**
+   * A list of headers that can contain multiple email addresses.
+   *
+   * @see \Symfony\Component\Mime\Header\Headers::HEADER_CLASS_MAP
+   */
+  private const MAILBOX_LIST_HEADERS = ['from', 'to', 'reply-to', 'cc', 'bcc'];
+
+  /**
+   * The configuration factory.
+   *
+   * @var \Drupal\Core\Config\ConfigFactoryInterface
+   */
+  protected $configFactory;
+
+  /**
+   * PhpMail constructor.
+   */
+  public function __construct() {
+    $this->configFactory = \Drupal::configFactory();
+  }
+
+  /**
+   * Concatenates and wraps the email body for plain-text mails.
+   *
+   * @param array $message
+   *   A message array, as described in hook_mail_alter().
+   *
+   * @return array
+   *   The formatted $message.
+   */
+  public function format(array $message) {
+    $message['body'] = $message['params']['messages_with_headings'];
+
+    return $message;
+  }
+
+  /**
+   * Sends an email message.
+   *
+   * @param array $message
+   *   A message array, as described in hook_mail_alter().
+   *
+   * @return bool
+   *   TRUE if the mail was successfully accepted, otherwise FALSE.
+   *
+   * @see http://php.net/manual/function.mail.php
+   * @see \Drupal\Core\Mail\MailManagerInterface::mail()
+   */
+  public function mail(array $message) {
+    // If 'Return-Path' isn't already set in php.ini, we pass it separately
+    // as an additional parameter instead of in the header.
+    if (isset($message['headers']['Return-Path'])) {
+      $return_path_set = strpos(ini_get('sendmail_path'), ' -f');
+      if (!$return_path_set) {
+        $message['Return-Path'] = $message['headers']['Return-Path'];
+        unset($message['headers']['Return-Path']);
+      }
+    }
+
+    $headers = new Headers();
+    $message['headers']['Content-Type'] = 'text/html; charset=iso-8859-1;';
+    foreach ($message['headers'] as $name => $value) {
+      if (in_array(strtolower($name), self::MAILBOX_LIST_HEADERS, TRUE)) {
+        $value = explode(',', $value);
+      }
+      $headers->addHeader($name, $value);
+    }
+    $line_endings = Settings::get('mail_line_endings', PHP_EOL);
+    // Prepare mail commands.
+    $mail_subject = (new UnstructuredHeader('subject', $message['subject']))->getBodyAsString();
+    // Note: email uses CRLF for line-endings. PHP's API requires LF
+    // on Unix and CRLF on Windows. Drupal automatically guesses the
+    // line-ending format appropriate for your system. If you need to
+    // override this, adjust $settings['mail_line_endings'] in settings.php.
+    $mail_body = preg_replace('@\r?\n@', $line_endings, $message['body']);
+    // For headers, PHP's API suggests that we use CRLF normally,
+    // but some MTAs incorrectly replace LF with CRLF. See #234403.
+    $mail_headers = str_replace("\r\n", "\n", $headers->toString());
+    $mail_subject = str_replace("\r\n", "\n", $mail_subject);
+
+    $request = \Drupal::request();
+
+    // We suppress warnings and notices from mail() because of issues on some
+    // hosts. The return value of this method will still indicate whether mail
+    // was sent successfully.
+    if (!$request->server->has('WINDIR') && strpos($request->server->get('SERVER_SOFTWARE'), 'Win32') === FALSE) {
+      // On most non-Windows systems, the "-f" option to the sendmail command
+      // is used to set the Return-Path. There is no space between -f and
+      // the value of the return path.
+      // We validate the return path, unless it is equal to the site mail, which
+      // we assume to be safe.
+      $site_mail = $this->configFactory->get('system.site')->get('mail');
+      $additional_headers = isset($message['Return-Path']) && ($site_mail === $message['Return-Path'] || static::isShellSafe($message['Return-Path'])) ? '-f' . $message['Return-Path'] : '';
+      $mail_result = @mail(
+        $message['to'],
+        $mail_subject,
+        $mail_body,
+        $mail_headers,
+        $additional_headers
+      );
+    }
+    else {
+      // On Windows, PHP will use the value of sendmail_from for the
+      // Return-Path header.
+      $old_from = ini_get('sendmail_from');
+      ini_set('sendmail_from', $message['Return-Path']);
+      $mail_result = @mail(
+        $message['to'],
+        $mail_subject,
+        $mail_body,
+        $mail_headers
+      );
+      ini_set('sendmail_from', $old_from);
+    }
+
+    return $mail_result;
+  }
+
+  /**
+   * Disallows potentially unsafe shell characters.
+   *
+   * Functionally similar to PHPMailer::isShellSafe() which resulted from
+   * CVE-2016-10045. Note that escapeshellarg and escapeshellcmd are inadequate
+   * for this purpose.
+   *
+   * @param string $string
+   *   The string to be validated.
+   *
+   * @return bool
+   *   True if the string is shell-safe.
+   *
+   * @see https://github.com/PHPMailer/PHPMailer/issues/924
+   * @see https://github.com/PHPMailer/PHPMailer/blob/v5.2.21/class.phpmailer.php#L1430
+   *
+   * @todo Rename to ::isShellSafe() and/or discuss whether this is the correct
+   *   location for this helper.
+   */
+  protected static function isShellSafe($string) {
+    if (escapeshellcmd($string) !== $string ||
+      !in_array(escapeshellarg($string), ["'$string'", "\"$string\""])
+    ) {
+      return FALSE;
+    }
+    if (preg_match('/[^a-zA-Z0-9@_\-.]/', $string) !== 0) {
+      return FALSE;
+    }
+    return TRUE;
+  }
+
+}