Drupal - Send attachments with drupal_mail

There might be other ways, but I have found that mailsystem and mimemail modules have to be installed to send email with attachment. So install these two modules first.

Then implement hook_mail to pass attachment to $message

/**
 * Implements hook_mail().
 */
function mymodule_mail($key, &$message, $params) {
  $message['subject'] = $params['subject'];
  $message['body'][] = $params['body'];

  // Add attachment when available.
  if (isset($params['attachment'])) {
    $message['params']['attachments'][] = $params['attachment'];
  }
}

There are two ways to add attachment, you can either pass filecontent or filepath when adding an unmanaged file as attachment (not recorded in DB) or pass file object when adding an managed file.

When adding unmanaged file:

$attachment = array(
  'filepath' => $filepath, // or $uri
);

or

$attachment = array(
  'filecontent' => file_get_contents($uri),
  'filename' => $filename,
  'filemime' => 'application/pdf'
);

By using filecontent way, you probably will get two php errors by Jan 08, 2015 including

• Warning: is_file() expects a valid path
• Warning: realpath() expects parameter 1 to be a valid path

When adding managed file:

$attachment = file_load($fid);

Then send email by:

$params = array(
  'key' => 'my_email_template',
  'to' => '[email protected]',
  'from' => '[email protected]',
  'subject' => 'Test email',
  'body' => 'test',
  'attachment' => $attachment
);

drupal_mail('mymodule', $key, $to, $language, $params, $from);

I remember I want did it before, I tried this and worked for me

function mymodule_mail($key, &$message, $params) {
  $data['user'] = $params['from'];
  $account = $data['user']->name;

  $file_content = file_get_contents('some/file/path');

  $attachments = array(
     'filecontent' => $file_content,
     'filename' => 'example-' . $account,
     'filemime' => 'application/pdf',
   );

  switch($key) {
    case 'notice':

      $langcode = $message['language']->language;
      $message = drupal_mail($module, $key, $to, $language, $params, $from, $send);
      $message['subject'] = 'example submission from '. $account;
      $message['body'][] =
        '<p>'. $account .' has submitted an example.</p>';
      $message['params']['attachments'][] = $attachments;
    $system = drupal_mail_system($module, $key);
    // Format the message body.
    $message = $system->format($message);
    // Send e-mail.
    $message['result'] = $system->mail($message);

    if($message['result'] == TRUE) {
        drupal_set_message(t('Your message has been sent.'));
    }
    else{
        drupal_set_message(t('There was a problem sending your message and it was not     sent.'), 'error');
    }
      break;
  }
}

$attachment = array(
      'filecontent' => $filepathname,
      'filename' => $namefile,
      'filemime' => 'application/pdf'
      );
//where $filepathname should contain the path to the file and $filename should contain the name of the file.
$to = '[email protected]'; // emails
$from = '[email protected]';

$params = array(
  'headers' => array('Content-Type' => 'text/html'),
  'key' => 'test',
  'subject' => 'Test email',
  'body' => 'test',
  'attachment' => $attachment
);

drupal_mail($module, $key, $to, $language, $params, $from, $send = TRUE);

This worked for me.