Same name and namespace in other branches
  1. 5.x includes/common.inc \drupal_mail()
  2. 7.x includes/mail.inc \drupal_mail()

Compose and optionally send an e-mail message.

Sending an e-mail works with defining an e-mail template (subject, text and possibly e-mail headers) and the replacement values to use in the appropriate places in the template. Processed e-mail templates are requested from hook_mail() from the module sending the e-mail. Any module can modify the composed e-mail message array using hook_mail_alter(). Finally drupal_mail_send() sends the e-mail, which can be reused if the exact same composed e-mail is to be sent to multiple recipients.

Finding out what language to send the e-mail with needs some consideration. If you send e-mail to a user, her preferred language should be fine, so use user_preferred_language(). If you send email based on form values filled on the page, there are two additional choices if you are not sending the e-mail to a user on the site. You can either use the language used to generate the page ($language global variable) or the site default language. See language_default(). The former is good if sending e-mail to the person filling the form, the later is good if you send e-mail to an address previously set up (like contact addresses in a contact form).

Taking care of always using the proper language is even more important when sending e-mails in a row to multiple users. Hook_mail() abstracts whether the mail text comes from an administrator setting or is static in the source code. It should also deal with common mail tokens, only receiving $params which are unique to the actual e-mail at hand.

An example:

function example_notify($accounts) {
  foreach ($accounts as $account) {
    $params['account'] = $account;

    // example_mail() will be called based on the first drupal_mail() parameter.
    drupal_mail('example', 'notice', $account->mail, user_preferred_language($account), $params);
  }
}
function example_mail($key, &$message, $params) {
  $language = $message['language'];
  $variables = user_mail_tokens($params['account'], $language);
  switch ($key) {
    case 'notice':
      $message['subject'] = t('Notification from !site', $variables, $language->language);
      $message['body'][] = t("Dear !username\n\nThere is new content available on the site.", $variables, $language->language);
      break;
  }
}

Parameters

$module: A module name to invoke hook_mail() on. The {$module}_mail() hook will be called to complete the $message structure which will already contain common defaults.

$key: A key to identify the e-mail sent. The final e-mail id for e-mail altering will be {$module}_{$key}.

$to: The e-mail address or addresses where the message will be sent to. The formatting of this string must comply with RFC 5322. Some examples are:

$language: Language object to use to compose the e-mail.

$params: Optional parameters to build the e-mail.

$from: Sets From to this value, if given.

$send: Send the message directly, without calling drupal_mail_send() manually.

Return value

The $message array structure containing all details of the message. If already sent ($send = TRUE), then the 'result' element will contain the success indicator of the e-mail, failure being already written to the watchdog. (Success means nothing more than the message being accepted at php-level, which still doesn't guarantee it to be delivered.)

5 calls to drupal_mail()
contact_mail_page_submit in modules/contact/contact.pages.inc
Process the site-wide contact page form submission.
contact_mail_user_submit in modules/contact/contact.pages.inc
Process the personal contact page form submission.
hook_watchdog in developer/hooks/core.php
Log an event message
_update_cron_notify in modules/update/update.fetch.inc
Perform any notifications that should be done once cron fetches new data.
_user_mail_notify in modules/user/user.module
Conditionally create and send a notification email when a certain operation happens on the given user account.

File

includes/mail.inc, line 85

Code

function drupal_mail($module, $key, $to, $language, $params = array(), $from = NULL, $send = TRUE) {
  $default_from = variable_get('site_mail', ini_get('sendmail_from'));

  // Bundle up the variables into a structured array for altering.
  $message = array(
    'id' => $module . '_' . $key,
    'to' => $to,
    'from' => isset($from) ? $from : $default_from,
    'language' => $language,
    'params' => $params,
    'subject' => '',
    'body' => array(),
  );

  // Build the default headers
  $headers = array(
    'MIME-Version' => '1.0',
    'Content-Type' => 'text/plain; charset=UTF-8; format=flowed; delsp=yes',
    'Content-Transfer-Encoding' => '8Bit',
    'X-Mailer' => 'Drupal',
  );
  if ($default_from) {

    // To prevent e-mail from looking like spam, the addresses in the Sender and
    // Return-Path headers should have a domain authorized to use the originating
    // SMTP server. Errors-To is redundant, but shouldn't hurt.
    $headers['From'] = $headers['Sender'] = $headers['Return-Path'] = $headers['Errors-To'] = $default_from;
  }
  if ($from) {
    $headers['From'] = $from;
  }
  $message['headers'] = $headers;

  // Build the e-mail (get subject and body, allow additional headers) by
  // invoking hook_mail() on this module. We cannot use module_invoke() as
  // we need to have $message by reference in hook_mail().
  if (function_exists($function = $module . '_mail')) {
    $function($key, $message, $params);
  }

  // Invoke hook_mail_alter() to allow all modules to alter the resulting e-mail.
  drupal_alter('mail', $message);

  // Concatenate and wrap the e-mail body.
  $message['body'] = is_array($message['body']) ? drupal_wrap_mail(implode("\n\n", $message['body'])) : drupal_wrap_mail($message['body']);

  // Optionally send e-mail.
  if ($send) {
    $message['result'] = drupal_mail_send($message);

    // Log errors
    if (!$message['result']) {
      watchdog('mail', 'Error sending e-mail (from %from to %to).', array(
        '%from' => $message['from'],
        '%to' => $message['to'],
      ), WATCHDOG_ERROR);
      drupal_set_message(t('Unable to send e-mail. Please contact the site administrator if the problem persists.'), 'error');
    }
  }
  return $message;
}