drupal_mail_system

Returns an object that implements the Drupal\Core\Mail\MailInterface interface.

Allows for one or more custom mail backends to format and send mail messages composed using drupal_mail().

An implementation needs to implement the following methods:

• format: Allows to preprocess, format, and postprocess a mail message before it is passed to the sending system. By default, all messages may contain HTML and are converted to plain-text by the Drupal\Core\Mail\PhpMail implementation. For example, an alternative implementation could override the default implementation and additionally sanitize the HTML for usage in a MIME-encoded e-mail, but still invoking the Drupal\Core\Mail\PhpMail implementation to generate an alternate plain-text version for sending.
• mail: Sends a message through a custom mail sending engine. By default, all messages are sent via PHP's mail() function by the Drupal\Core\Mail\PhpMail implementation.

The selection of a particular implementation is controlled via the variable 'mail_system', which is a keyed array. The default implementation is the class whose name is the value of 'default-system' key. A more specific match first to key and then to module will be used in preference to the default. To specificy a different class for all mail sent by one module, set the class name as the value for the key corresponding to the module name. To specificy a class for a particular message sent by one module, set the class name as the value for the array key that is the message id, which is "${module}_${key}".

For example to debug all mail sent by the user module by logging it to a file, you might set the variable as something like:

array(
  'default-system' => 'Drupal\Core\Mail\PhpMail',
  'user' => 'DevelMailLog',
);

Finally, a different system can be specified for a specific e-mail ID (see the $key param), such as one of the keys used by the contact module:

array(
  'default-system' => 'Drupal\Core\Mail\PhpMail',
  'user' => 'DevelMailLog',
  'contact_page_autoreply' => 'DrupalDevNullMailSend',
);

Other possible uses for system include a mail-sending class that actually sends (or duplicates) each message to SMS, Twitter, instant message, etc, or a class that queues up a large number of messages for more efficient bulk sending or for sending via a remote gateway so as to reduce the load on the local server.

Parameters

$module: The module name which was used by drupal_mail() to invoke hook_mail().

$key: A key to identify the e-mail sent. The final e-mail ID for the e-mail alter hook in drupal_mail() would have been {$module}_{$key}.

Return value

Drupal\Core\Mail\MailInterface

2 calls to drupal_mail_system()

File

core/includes/mail.inc, line 258

API functions for processing and sending e-mail.

Code

function drupal_mail_system($module, $key) {
  $instances = &drupal_static(__FUNCTION__, array());

  $id = $module . '_' . $key;

  $configuration = variable_get('mail_system', array('default-system' => 'Drupal\Core\Mail\PhpMail'));

  // Look for overrides for the default class, starting from the most specific
  // id, and falling back to the module name.
  if (isset($configuration[$id])) {
    $class = $configuration[$id];
  }
  elseif (isset($configuration[$module])) {
    $class = $configuration[$module];
  }
  else {
    $class = $configuration['default-system'];
  }

  if (empty($instances[$class])) {
    $interfaces = class_implements($class);
    if (isset($interfaces['Drupal\Core\Mail\MailInterface'])) {
      $instances[$class] = new $class();
    }
    else {
      throw new Exception(t('Class %class does not implement interface %interface', array('%class' => $class, '%interface' => 'Drupal\Core\Mail\MailInterface')));
    }
  }
  return $instances[$class];
}